quote:

In the second case of the rifle with a bulged chamber there's pretty strong evidence of what probably happened. I bought the rifle from the freind with it he sent 4 or 5 different loads he had been shooting in the rifle. They were SEVERAL grains over the listed maximums in several different manuals. Of course I didn't shoot them but pulled the bullets and dumped the rest. I shot the rifle for a year or two and it did NOT have a bulged chamber. I liked the rifle but needed money for a hunting lease and sold the rifle back to the friend. A couple of years later we were working on another trade deal and I asked about the same rifle, since the time I owned it it somehow had aquired a bulged chamber and he said that he had to send it off to be rechambered for a caliber that cleaned up the bulge. Needless to say the rifle had lost it's appeal to me. It seems pretty obvious that the rifle (a Winchester Featherweight) had returned to a diet of high pressure loads that caused the bulge in the chamber.

Wrong powder or over charge.
You can't tell the difference.
Did he have any blown cases or blown primers.
Your words are basically worthless blabbing with no facts.

quote:

Originally posted by Hot Core:

quote:

Originally posted by Grumulkin:
...the numbers of reloaders who acknowledge that velocity is not a reliable indicator of excess pressure has risen dramatically.

I'm always glad to see people recognize Reality instead of incorrect, totally wrong, wishful thinking.
-----

I've had Fast Barrels, Slow Barrels and Barrels inbetween. All a person has to do is gather a few rifles chambered for the same Cartridge, use the same ammo in each and it becomes obvious. Just as Saeed noted with the 150fps, but it could be even higher.

The previous 7mmRemMag I had was made with a Fast Barrel. It was due to the Bore being slightly larger than other 7mm rifles. My current 7mmRemMag has a Slow Barrel, which is actually a bit tighter than other 7mm barrels. And there are Chamber dimensional differences between them also. All of which adds up to some being Fast and some being Slow - just more Reality.
-----

Count me, as usual, among the folks who understand it is completely impossible to tell what the Pressure of a Cartridge is from looking at a Velocity. Too many Variables prevent it from happening, regardless of how well your individual Cartridge components match what is used in a Manual or Manufacturers Web Site.

I agree with you on barrels you can change twist,rifling,length etc and that can increase velocity most I've seen is around 100fps.

I always work up my loads and when I get one that shooting pretty good then I'll chronograph. I start checking velocity with my start loads then work up and I find most times 1 to 1.5gr below max is at published velocity.

There is a value on the barrel for some added velocity and there some load may not give an extra velocity. I think measuring CHE is pretty reliable.

I'm more concerned with groups over velocity and I shoot with some guys who don't own a chronograph and I've offer mine if they want to use it and they are happy quoting book velocity over finding out what there are really getting.

Chronograph is a tool.

DJ - I sure didn't mean to take your thread down a different path. I must admit that at first reading I felt you were putting way to much faith in the velocity/pressure book data. As I've stated I feel it is another piece of data. Since I load more wildcats than STD and choose to load my various 7x57 & 06 based cases to around 65,000 as a max not the Saami the data means even less to me.

I will be the first one to jump on the band wagon saying there is no such thing as a free lunch. With velocity comes pressure. You just have more faith in the book data than I do. To be honest the latest load book I have purchases is a Nosler # 4. Book data is only a starting point for me. Maybe the new books are doing a lot better job of documenting and testing. I do feel that a good quality pressure barrel universal reciever set up gives a lot better data than the old books listing what factory rifle they used for testing. Or Hornady's quote of using the same slope line for all IMR powders stopping at a full case or .0004" expansion per their test brass and rifle.

303 and others yes it hurt to lose a lot of my backup and support data. I know how my friend felt and the hours he and his son spent walking the ditches recovering what he did and the look on his face when he came to tell me. Data is only a thing a "friend" is worth far more. As to the ex she is the one that put a capital "B" in the word. I went from 25 years of pure he!! to being married to a wonderful woman that loves to hunt and shoot as much or more than I do. Again the loss of the data was worth it.

As to my PDK series of wildcats. I use them and play with them. Been sharing the 400 data on the wildcat thread and the 380 version has loads ready for testing. Several friends and family use them. But Rocky had done it before I simply use a 280 case not 06 and 40 deg not 35. Then along came the Hawk and Howell series. Heck they have far more time and $$ than I do.


What I do wish is that I had more of my AI test data. Then again the shooters who feel that Ackley figured out how to magically add velocity without pressure sure don't want to hear from me. I built my first AI and even reached many of the claimed velocities. Then I started pressure testing(yes with Ken's Model 43 and yes wish it were still around) using the same barrel as a STD then AI. I will go to my grave saying that from "MY TESTING" the majority of the gain from an AI is pressure or comparing new load data to old low pressure rds like the 7x57 or 257R(heck that is still pressure). Since a majority of my before and after data is lost the only thing I can share is my experience. I found that many of my AI loads were way above 70,000. That adding a .5gr of powder to a no pressure sign load all of a sudden blew the primer. A AI style case hides the pressure (some say it simply handles it better) it is still there or you don't see the velocity gain. If you feel comfortable with 70,000 psi plus or loads that are only safe below a certain temperature that is your choice. I used to load that way now days If the load isn't safe at any and all temperatures or I can't get 5-10 loadings it is to hot for me. Remember guys this comes from a guy with his own set of wildcats that add even more capacity than a AI and use his 40deg shoulder. I accept the velocity claims that people make I wasn't there. But the quickest way to get velocity is pressure. Heck even with all my testing I jumped out and built several 7STW's. Last one is still for sale if anyone wants it.

I sure don't claim to be an expert. There are others with far more knowledge and experience than I have. Many are comfortable letting the given rifle and brass set a max pressure I'm no longer one of them. I've had brands of brass(even different lots of the same) start to show pressure at points 5-7500psi different. I use the same lot Norma 280 brass for a majority of my wildcat work. I'm comfortable as long as I have NO expansion I'm at or under 65,000(as determined by my testing). I do feel that adding a little capacity in some cases allow gives you the space needed to use a slightly slower powder or like in the case of my 400PDK the space to use more of a faster powder moving closer to being pressure limited not space limited.

As to Saeed's question on his 404 or DJ your 9.3x62. The older lower max pressures were there for a reason at the time. Be it rifle construction, metal, brass quality or even Remington building a 280 in their auto. Provided I have a new quality bolt action and new design brass I feel that if 65,000 is safe for a 270 case it is safe for any 06 based. Likewise 65,000 for a 6mm makes it good for a 7x57. As Tigertate has discussed with me in the past make sure of the quality of your brass. He pointed out that he had seen a major difference in the web area of old 9.3x62 brass versus new. If a 375H&H and other magnum cases can be loaded safely to 61-62,000 I see no reason a 404 of the same quality should be stopped at 52950.

Sorry guys sure didn't mean to spend so much time on the soap box. Remember guys the above in my findings and opinion. Remember opinions are like a$$holes everyone has one.

quote:

Originally posted by ramrod340:
DJ - I sure didn't mean to take your thread down a different path.

Ramrod340, Far from taking the thread down a different path your comments are exactly the kind of experience and fact based comments that I was hoping to elicit. I appreciate your comments and information. I think we agree pretty closely on most of the major points.

You and a couple other posters have restated some of the points I was trying to make in better ways that I made them. One of the most respected names in the industry corrected one of my misconceptions. I'm pretty happy with the results of this thread and hope it can continue.

I may be extending things too far without some pressure testing to assume that if I'm using all the same components and same length barrel and getting the same velocity that I'm pretty near the same pressure. I still think that this is true but obviously it needs to be verified by actual pressure testing before I could consider it fact.

I am however even more convinced than ever that the Pressure Tested Book maximum velocities are velocity's that you aren't going to exceed with the same components without excessive pressure. Several posters here have reinforced this opinion.

As far as the 404 being capable of being loaded to the same std pressures as other rounds, it is similar to the 9,3x62. I was fortunate to be able to access some pressure tested data on the loads I was using so I felt comfortable doing so. If someone is doing the same with the 404 Jeffrey if they have pressure tested data to confirm it with it shouldn't be any real problem with one Caveat. One of the appeals of a large case caliber like the 404 Jeffrey is that it operates at lower pressures which is considered by many African Hunters to be a real advantage. I know of several who prefer the 416 Rigby over the 416 Remington even though they are ballistically identical in factory loads. The Rigby is a lower pressure round than the 416 and the larger action it requires isn't that much of an issue in a rifle you don't want to be too light anyway.

I guess that if you can confirm that your loads aren't exceeding 62-65K PSI in modern rifles with quality brass you really shouldn't run into any problems.

But again please feel free to add anything else you'd like to on this thread, you have improved it greatly...................................DJ

quote:

Hot Core, you are deceiving yourself if you think that your "Fast Barrel" is going to acheive faster than normal velocities without higher pressures.

OK now I would like to understand better, a larger bore and a larger chamber with perhaps a longer throat would be expected to produce lower pressure with the same load as compared to another barrel, right? That's because there is a slower pressure build up which translates into a lower peak pressure and a lower mean pressure, right?

Now, develop a load for that particular barrel to the as near as possible same pressure as the comparison barrel and the result will be a higher velocity, right? That would make 'our' barrel a faster barrel, right?

(Which only confuses the issue further. )

quote:

Originally posted by SR4759:

quote:

In the second case of the rifle with a bulged chamber there's pretty strong evidence of what probably happened. I bought the rifle from the freind with it he sent 4 or 5 different loads he had been shooting in the rifle. They were SEVERAL grains over the listed maximums in several different manuals. Of course I didn't shoot them but pulled the bullets and dumped the rest. I shot the rifle for a year or two and it did NOT have a bulged chamber. I liked the rifle but needed money for a hunting lease and sold the rifle back to the friend. A couple of years later we were working on another trade deal and I asked about the same rifle, since the time I owned it it somehow had aquired a bulged chamber and he said that he had to send it off to be rechambered for a caliber that cleaned up the bulge. Needless to say the rifle had lost it's appeal to me. It seems pretty obvious that the rifle (a Winchester Featherweight) had returned to a diet of high pressure loads that caused the bulge in the chamber.

Wrong powder or over charge.
You can't tell the difference.
Did he have any blown cases or blown primers.
Your words are basically worthless blabbing with no facts.

I think that with the vast majority of knowledgeable reloaders if they knew someone was loading ammo with loads 6-8grs over the listed maximums and later the rifle developed a bulged chamber they would find it highly likely that the two were related.

It's a little sad that you are so bitter over being proven wrong on another thread. I still hope that instead of continuing with personal insults you might be able to find something more positive to add. Don't let anything you read on the internet get you too upset, this is all for learning and fun........................................DJ

quote:

It's a little sad that you are so bitter over being proven wrong on another thread.

You should run for Congress DJ ...you seem to be chronically confused ...

quote:

Originally posted by 303Guy:

quote:

Hot Core, you are deceiving yourself if you think that your "Fast Barrel" is going to acheive faster than normal velocities without higher pressures.

OK now I would like to understand better, a larger bore and a larger chamber with perhaps a longer throat would be expected to produce lower pressure with the same load as compared to another barrel, right? That's because there is a slower pressure build up which translates into a lower peak pressure and a lower mean pressure, right?

Now, develop a load for that particular barrel to the as near as possible same pressure as the comparison barrel and the result will be a higher velocity, right? That would make 'our' barrel a faster barrel, right?

(Which only confuses the issue further. )

Uh NO. Rifles with fat chambers and loose throats and other tolerances do lower pressure, they also lower velocity. My long throated WSM's demonstrate this. To acheive the same velocity you have to add powder which raises pressure. You aren't going to be able to add enough more powder to increase the velocity past a tighter barrels velocities without the added powder also increasing pressure to above the pressure levels of the other barrel.

Please do understand that there is variation between each and every barrel and some ammo has velocity variations from shot to shot. I don't think that a velocity difference of 50-75 or maybe even 100fps is going to make a huge difference in pressures on most hunting rifle cartridges. The main thing that I want to get across is that there isn't some magic combination of components that will let you shoot your rifle 200-300fps faster than current data shows. I've known too many reloaders that push the envelope further than I think is save and have seen blown up guns and damaged firearms as a result. A guy shooting 3150 with 180gr bullets in a 24" 300 Win Mag doesn't really worry me, it's the guy shooting the same 180's in a 24" 300 Win Mag at 3300 that does.........................DJ

One must always remember that pressure alone is not the cause of velocity. It's more "the time the pressure is applied."

The so-called "fast barrels" may in some manner actually allow the pressure to be held longer. We really don't know and any insinuation that faster means higher pressure is a guess and not supported by proof.

quote:

Originally posted by rolltop:
We really don't know and any insinuation that faster means higher pressure is a guess and not supported by proof.

This statement makes me wonder if you have ever really read a reloading manual.............................DJ

quote:

One must always remember that pressure alone is not the cause of velocity. It's more "the time the pressure is applied."

Well, one barrel might just do that and if the friction in that barrel also happens to be lower over its length that would make sense. Perhaps a larger chamber with a rougher leade may burn more of the powder earlier without raising pressure which would then result in a higher mean pressure and velocity. Who knows? I do know that my hornet can do stuff that other hornets cannot. And then only in a specific case. Funny things go on inside a chamber and barrel! But I do agree that if a particular barrel is 'faster' with the same load as another then it follows that the peak pressure is higher too.

How does one explain a barrel that heats up very rapidly and evenly that then stays cool by just a small increase in powder charge? Without any major change in pressure? (On average, the primers were slightly less rounded on the edges).

Oops! This thread is about using a chronoghraph - I didn't actually measure the change in velocity! I only infered a higher velocity by greater penetration of wood and a flatter trajectory (slightly) and by the sharper feel to the recoil. (Qualitative assessment).

quote:

Originally posted by djpaintles:

quote:

Originally posted by rolltop:
We really don't know and any insinuation that faster means higher pressure is a guess and not supported by proof.

This statement makes me wonder if you have ever really read a reloading manual.............................DJ

I've read several of them. Have you ever taken a class in integral calculus?

If you had then you would understand my point.

quote:

Originally posted by rolltop:

quote:

Originally posted by djpaintles:

quote:

Originally posted by rolltop:
We really don't know and any insinuation that faster means higher pressure is a guess and not supported by proof.

This statement makes me wonder if you have ever really read a reloading manual.............................DJ

I've read several of them. Have you ever taken a class in integral calculus? Of course, it was a first year course in College

If you had then you would understand my point.

You are correct that it's not just peak pressure but the total spread of pressure over time. What can you possibly mean that there is no proof that higher velocity means higher pressure? Please reread Ken Oehlers post. Read the warnings in every single reloading manual that exceeding the maximum loads means you are exceeding maximum pressures. They've done thousands of hours of detailed pressure testing, some list the pressure at both lower and higher velocities what further proof do you need?.................................DJ

Here is my 2 cents, you can put in a rem .223 case with a 50gr HPBT.... 27.5 grains of varget and then 25.9 grains of H335 and you will have basically an exact velocity +/- 10fps but a pressure range of 44,800 with varget and 51,700 with h335, so there is a HUGE difference in pressure, meaning that your claims are not correct... DJ we worked together in the oil in your chamber issue but I'm afraid your wrong on this one!...

quote:

Originally posted by djpaintles:
Hot Core, you are deceiving yourself if you think that your "Fast Barrel" is going to acheive faster than normal velocities without higher pressures.

Hey dj, I do understandwhat you are saying, but in the case of the rifle I was speaking about, you are simply mistaken. I also understand what Dr. Oehler was talking about, but it describes a different set of circumstances. My "Fast Barrel" 7mmRemMag and other "Fast Barrel" First Generation M77 Rugers. It is my understanding Ruger outsourced their barrels at that time and everyone of them I had exhibited a Fast Barrel.

I had noticed all the Bores were slightly larger than other manufacturers rifles of the same Calibers. Thought it a bit strange at first, but eventually decided Ruger must have Specified the Bores/Lands be slightly large. I saw it on too many for it to be a coincidence.

If you know anyone who has a First Generation M77 with the original barrel, run a Bore Brush through it and then run the same Bore Brush through a different manufacturers rifle of the same Caliber. I feel sure if anyone out there tries that easy Test, they will find the Bore Brush takes much less effort to push through the Ruger. I tended to use the next larger Bore Brush in the ones I had because of it.

quote:

if you think that there are 24" barrels that will allow you to shoot 180gr bullets in a 300 Win Mag at 3250fps you are dead wrong.

My 300WinMags were not the old Rugers, so I don't know what one of them woul shoot at a Safe Pressure.

quote:

You don't need to listen to me but you should listen to one of the top experts alive in the feild - Ken Oehler. " If your chronograph readings approach max book velocity, you can assume that you have reached, or have already exceeded, max pressure. "

Identical" barrels don't exist. Just because they came from the same maker, drilled with the same drill, chambered with the same reamer, and measure identical, they probably will not fire the same pressure and velocity. You can assume that if you get a higher velocity, it came at the cost of higher pressure. ".

Well, I know the Pressure was not too high in my old Rugers and I know I was dumping in a lot of Powder to get the CHE/PRE where it was a Safe Max. Only because that is the same way I've always loaded my rifles for Hunting.

I also remember the Velocity being above the listings in the Manuals, but I can't tell you what they were because all my data went with those rifles when I sold them.

Once I began using Remington rifles, I've very rarely seen a situation where I consider it OK to exceed the Manuals I reference. My current Remington 7mmRemMag has a very accurate "Slow Barrel". It reaches a Safe Max Pressure before reaching the Manual Max Loads. But, I plan to keep it because of the accuracy.

quote:

There is NO SUCH THING as barrels that will allow you to signifigantly exceed Pressure tested reloading manual velocities without exceeding normal pressures. ...DJ

I really have no desire to argue with you or anyone else, but my first-hand experience, with the old Rugers, has shown those thoughts to be incorrect. If I was only talkng about my Remington rifles, I'd agree with you, also from first-hand experience.
-----

Thanks Tom, We apparently load in a similar fashion.
-----

Where are you Dave?

Best of luck to you folks.

From what I read in the Lyman manual in the chapter titled "Controlling Pressure", DJ is correct.

I think that some are missing the point about the pressure/ velocity issue. It is unique to each individual powder. Yes, two totally different powders could yield the same velocity, but with different burn rates they produce different pressures.

DJ's point is specifically about exceeding the max speed with a single specific powder. I believe he is saying that for published data for that specific powder if the max velocity for that specific powder is exceeded, then you are over-pressure, even if your rifle brass or rifle exhibits no visible or perceptible signs of the over-pressure. This is correct and consistent with what I have read elsewhere.

quote:

DJ's point is specifically about exceeding the max speed with a single specific powder. I believe he is saying that for published data for that specific powder if the max velocity for that specific powder is exceeded,

I don't agree with this.
What he is saying is that if the velocity is normal the pressure has to be normal. That is not necessarily true. I could be either higher or lower. This is especially true with data shot with production rifles as opposed to pressure test barrels. At best it is an "in the ball park" estimate.

Did I not I give a clear enough answer to this earlier?

quote:

Originally posted by djpaintles:

quote:

Originally posted by rolltop:

quote:

Originally posted by djpaintles:

quote:

Originally posted by rolltop:
We really don't know and any insinuation that faster means higher pressure is a guess and not supported by proof.

This statement makes me wonder if you have ever really read a reloading manual.............................DJ

I've read several of them. Have you ever taken a class in integral calculus? Of course, it was a first year course in College

If you had then you would understand my point.

You are correct that it's not just peak pressure but the total spread of pressure over time. What can you possibly mean that there is no proof that higher velocity means higher pressure? Please reread Ken Oehlers post. Read the warnings in every single reloading manual that exceeding the maximum loads means you are exceeding maximum pressures. They've done thousands of hours of detailed pressure testing, some list the pressure at both lower and higher velocities what further proof do you need?.................................DJ

Reason they say don't load over max is alot don't own a chronograph so velocity means nothing. I've shot lots of deer/elk never chronographed some rifles.

My understanding to this point from what I have read here and in reloading manuals is that velocity is directly tied to pressure. If the velocity of a particular load increases with incremental additions of powder, then so does pressure. They are married, and increase together. If all things are equal between the test gun and your gun (the barrels are the same length thus the "combustion chamber" is the same volume), then exceeding the published velocity max is a good indication you are exceeding the pressure listed.

Example:
I shot some great groups with my .300 WM yesterday with a load that was 1gr. under max. The chronographed velocity of that load was 150fps over what the published data said the MAX load would be (which would have been 1gr. more powder). This thread made me carefully inspect my cases and I found signs of over-pressure. The primers were cratered.

In my case, the velocity being well over what the published max was, was consistent with what DJ states. Velocity over published max= over-pressured load, and there were visible signs to prove it.

My bullet puller will get a .223 workout tomorrow.

quote:

Originally posted by rcamuglia:

DJ's point is specifically about exceeding the max speed with a single specific powder. I believe he is saying that for published data for that specific powder if the max velocity for that specific powder is exceeded, then you are over-pressure, even if your rifle brass or rifle exhibits no visible or perceptible signs of the over-pressure. This is correct and consistent with what I have read elsewhere.

Once again someone is kind enough to clarify a point and say it better than I can. Thanks rcamuglia

quote:

originally posted by SR4759

I don't agree with this.
What he is saying is that if the velocity is normal the pressure has to be normal.

And once again someone is saying something absolutely incorrectly and not at all what I was trying to say.
I guess you take the good with the bad.


Rolltop, Maybe a way to understand it in Math/Physics term is this.
1. There is a specific amount of energy contained in a specific amount of a specific powder.
2. Test barrels are made to minimum tolerances that maximize the pressure and therefore velocity that is obtainable with a specific amount of powder/bullet/cartridge combination. The variances found in other rifles are going to be things that decrease the velocity obtainable with that amount of energy.

There are a few things that might make a barrel more efficient than a given pressure barrel. Polygonal rifling has been known to increase the velocity obtainable in some rounds without increase pressures, just be sure you are using data obtained from a polygonal bore if you are matching them up.


Hot Core, I see what you are saying. But you didn't actually pressure test the loads you got the higher velocities with did you? I assume that you used Case-Head Expansion to judge pressures with. There's been some rather lengthy threads argueing the pro's and con's of case head expansion, I've used it when there wasn't any data available for a given cartridge. Suffice it to say that Case Head Expansion was one of the major tools in writing some of the older reloading manuals. In the newer manuals where they did actual pressure testing quite a few of the old loads developed with CHE were found to be too hot and the newer manuals have lower max loads for quite a few cartridges.
I would bet that if you had loads in your old Rugers that were 200fps or more faster than is currently tested as max loads they would be at substantially higher than normal pressures, 50-75 fps is probably normal variation. I'm sure you would probably disagree with this but unfortunately without the rifles to actually pressure test the loads with we'll probably never really know for absolute sure.


Windtech, I was referring to specific amounts of specific powders with a specific bullet not comparing velocities obtainable with different powders like you thought. - Just a misunderstanding.

I also would reiterate that some rifles WON'T even be able to acheive the same velocity's using the maximum powder charges without going over pressure. Some barrels have rougher bores, larger chambers etc. that might prevent them from acheiving the same velocities that other barrels will. There are "Slow Barrels" that shoot slower at the same pressure as other barrels. There are not "Fast Barrels" that will sshoot SIGNIFIGANTLY faster than any velocity listed in a current pressure tested manual with the EXACT SAME POWDER AND BULLET without higher pressures than those tested...............................DJ

quote:

I also would reiterate that some rifles WON'T even be able to acheive the same velocity's using the maximum powder charges without going over pressure. Some barrels have rougher bores, larger chambers etc. that might prevent them from acheiving the same velocities that other barrels will. There are "Slow Barrels" that shoot slower at the same pressure as other barrels. There are not "Fast Barrels" that will sshoot SIGNIFIGANTLY faster than any velocity listed in a current pressure tested manual with the EXACT SAME POWDER AND BULLET without higher pressures than those tested...............................DJ

It's just physics!

quote:

Originally posted by djpaintles:

quote:

Originally posted by Saeed:
I have no idea what is causing this.

But, I have a Remington 300 Ultra mag which has higher velocity than a 30-378 Weatherby!!? You are shooting loads that are well above std. pressure

Dr. Oehler mentioned pressure, which brings up a point I have been taken to task about.

We developed loads for our 404 Jeffery, built on a Sako 75 action. Getting velocities higher than factory loadings. You are shooting them at higher than normal pressures. What you are seeing is a well made rifle that often pretty much comes "blueprinted" from the factory and won't show traditional pressure signs as quickly as a rifle that isn't as squared up as the Sako's usually are

We have shot the same brass cases several times, and neither they nor the rifle showed any sign of excessive pressure. But, some members insisted that we are playing a dangerous game by using loads which are of much higher pressure than acceptable.

This brings me to the point.

What is an acceptable pressure IN ANY PARTICULR rifle? In a strong modern action loads that are in the 65,000psi range should be acceptable, I beleive this is about the highest allowed pressures by SAAMI

On the other end of the scale.

I have had European built rifles that showed signs of excessive pressure with both factory ammo and minimum loaded reloads. Tight bores, tight throats? You may or may not be able to load them to normal velocities for the caliber

Where does oen drwa the line?

Here in our range we stop as soon as we encounter stiff bolt lift, flattened primers etc. This was the same method that they originally used to develop loads for the 7 STW. When they actually got around to Pressure testing the loads they found that they were WAAYY over acceptable pressures. STICKY BOLT LIFT IS A UNRELIABLE PRESSURE INDICATOR!, flattened primers can also be deceptive. The freinds that I know that used these methods ended up with their rifles in peices and/or with bulged chambers.
Why try and push the limits of a given caliber so much? I've seen some of your videos you have guns that are MORE than powerful enough for the job!

Ramrod, It's unfortunate that you lost all of your data! If you were pressure testing with an Oehler 43 and keeping careful notes of powders and bullets I'd probably been happy to use your data if I had a rifle in your Wildcat calibers. It sounds like you had a good thing going and were careful not to exceed 65k psi with them.
I use a few loads that are above the std. low pressure limit for the 9,3x62. They are pressure tested to be below 60k psi but are above the std CIP loads found in manuals, SAAMI doesn't have a std for 9,3x62 but the for the rifles I shoot them in 60K psi is perfectly safe. I could probably just as safely load them to 65K PSI with the high quality brass and newly manufactured rifles I shoot them in but I don't find it necessary to push them to the edge.
I do wish that Mr. Oehler would produce the Model 43 again.............................DJ

Thank you.

I think we have reached the same conclusions too.

And as long as those loads are safe in our own rifles, we will continue to use them.

Looking back at my notes, we had a BRNO 243 that would not shoot factory ammo safely at all.

Factory ammo would blow the primers completely off the case, enlarging the pockets that the primers would fall out.

I tried loads which were reduced below minimim book, still had pressure signs.

We could not see where the problem was, so we slugged the barrel.

It turned out it had a very tight barrel - 0.239".

quote:

Originally posted by djpaintles:
I also would reiterate that some rifles WON'T even be able to acheive the same velocity's using the maximum powder charges without going over pressure. Some barrels have rougher bores, larger chambers etc. that might prevent them from acheiving the same velocities that other barrels will. There are "Slow Barrels" that shoot slower at the same pressure as other barrels. There are not "Fast Barrels" that will sshoot SIGNIFIGANTLY faster than any velocity listed in a current pressure tested manual with the EXACT SAME POWDER AND BULLET without higher pressures than those tested...............................DJ

This is a crock.
You are using the weasel word significantly working only in one direction.

This is saying barrels may never go significantly faster but may go significantly slower for a specific pressure. That can't be true given all the variables that affect pressure. Saeed mentions the blown primer rifle. You could do the same thing with the various versions of the GEW 88 which have multiple bore and groove combinations.
This was also documented in a Handloader Magazine article. The rifle was a Ruger 7X57 with an oversize bore. It gave higher velocities with standard pressures as given by the case. I consider cartridge case life a much more accurate predictor of safety than any chronograph. Blown primers are unsafe no matter what you chronograph says.

quote:

We could not see where the problem was, so we slugged the barrel.

It turned out it had a very tight barrel - 0.239"

Finally - after two threads and pages of nonsense someone offers something of value.

Most barrels are about as true as a goats colon and most mass produced bullets are all over the map. An over spec bullet driven through an under spec bore will drive pressures way over any faux max load from a book. The difference between a rifle and a bomb is a few thou.

I think once one gets to a blown primer, he has gone far too high in pressure.

We are lucky in a sense that we have an indoor shooting range, connected to our loading room.

So we load one sample and shoot it, then load another based on the results we have gotten.

quote:

Originally posted by djpaintles:
OK here's my point. An accurate chronograph WITHIN LIMITATIONS, can be the best indicator of pressure an average reloader can own. As an example if you find a load in one of the new pressure tested manuals that says for the 300xyz if you load 75grs of Powder X for a 180gr bullet they get 60,000psi and 3100fps in a 24" barrel. If you load the same 75grs of powder X in a 24" barrel with a 180gr bullet and your chronograph shows the load at 3100fps you are probably near 60,000psi.
At this point I can agree.
Now if you are loading the same powder and bullet and are getting 3300fps you are at HIGHER PRESSURE than 60,000psi! At this point we part our agreement. Had we said "Probably" we'd have been in tune. But to say that this is a definite conclusion is not an "automatic".

OK, Flame away. Everyone has their opinions but opinions supported by facts and data are far more valued than groundless ones ........................................ DJ

quote:

most mass produced bullets are all over the map.

I have an incredibly precise 0-1 Mitutoyo micrometer and frequently measure bullet diameters and have never (yet) found a bullet more than .001 from the "nominal" for the caliber. As a matter of fact the largest majority fall within .0002 of the nominal for the caliber.

What makes your Micrometer "incredibly precise" ...??

Who calibrated your micrometer ...??

Is .001" good for you ...??

How precise is the bore of the matching barrel ...??

I have a micrometer so accurate that the temperature has to be reasonably controlled to read the last few digits meaningfully. I don't use it. It would have been calibrated by the manufacturer. It's one of those that can be plugged into a computer.

quote:

Originally posted by Macifej:
most mass produced bullets are all over the map.

Please tell us the variance you have measured.

quote:

Originally posted by rcamuglia:

DJ's point is specifically about exceeding the max speed with a single specific powder. I believe he is saying that for published data for that specific powder if the max velocity for that specific powder is exceeded, then you are over-pressure, even if your rifle brass or rifle exhibits no visible or perceptible signs of the over-pressure. ....

The only problem is, the statement is not true in all rifles. On the other hand, it is an excellent statement for the Beginners and Rookies to operate from when thinking about Loads in general.

quote:

Originally posted by djpaintles:
Hot Core, I see what you are saying. But you didn't actually pressure test the loads you got the higher velocities with did you? I assume that you used Case-Head Expansion to judge pressures with.

That is correct.

quote:

I would bet that if you had loads in your old Rugers that were 200fps or more faster than is currently tested as max loads they would be at substantially higher than normal pressures, 50-75 fps is probably normal variation. I'm sure you would probably disagree with this but unfortunately without the rifles to actually pressure test the loads with we'll probably never really know for absolute sure.

I disagree. Back then I had access to three Chronographs. Wasted a lot of time messing with them.

The part "I believe" is creating the confusion for you is "perhaps" your lack of faith in being able to see Pressure Indications(repeatable, reliable, expansion) when measuring the CHE using a 0.0001" capable Micrometer. If a person does the measurement correctly and can detect no measurable change, then the Pressure is Low.

NOTE: CHE should not be used on old Low Pressure Cartridges like a 38Spl, 30-30, 35Rem, 45-70. In these situations, PRE works, and works well.

As the Pressure increases, eventually the Case Head, Extraction Groove, and Primer Pocket will all begin to Expand. It is the reality of the way things work. Without that understanding, it will be beyond the comprehension of a person to grasp how Pressure actually works in a Cartridge.

So, those people who do understand can then move to the obvious question, "How much Pressure Expansion is too much?" This is a debatable issue since some folks want the utmost Case Life and some are happy with 10-12 reloads. If utmost case Life is the goal, then Zero CHE helps achieve what that person wants. The other person will find a certain amount of CHE begins to create loose Primer Pockets which at some point makes the Case un-usable.

All of that needs to be understood prior to being able to comprehend that if powder is added to the Load, if the Velocity Increases, and if there is " NO " measurable CHE, then you are still at Low Pressure. You could do that in my old First Generation Rugers until you exceeded all the Manuals I had at the time by "X"grains. As you went to "X+1, X+2, X+3, X+4" you eventually got to the point where you had measurable CHE and the Velocity was above the MAX Velocities shown in the Manuals.

The CHE was not excessive though. As a Test, I selected 3-7mmRemMag Cases and was able to fire them 33 times each before one had a Neck Split. I had not been Annealing them along the way. The Primer Pockets were "looser" than when new, but I attributed it to mechanical wear as opposed to Expansion due to Pressure, however it was probably a bit of both.

That is the way those old Rugers worked, believe it or not.

I've thought of something that may throw a wrench into the cogs

When working up loads with my chronograph, I've frequently hit a point where the incremental additions of powder do not result in a incremental increase in velocity. I have noticed increased pressure signs at this point sometimes as well.

I don't think that increasing pressure (with powder additions) always results in an increase in velocity ie. they are not linearly tied together in a smooth curve.

Can someone chime in on this?

quote:

Originally posted by rcamuglia:
When working up loads with my chronograph, I've frequently hit a point where the incremental additions of powder do not result in a incremental increase in velocity.

Can someone chime in on this?

Absolutely true. many may have an explanation but for the most part they are all guessing. Possibly logically so but still guessing.

If one uses a Chrony he will see this. Just accept it as data and make decisions accordingly.

quote:

When working up loads with my chronograph, I've frequently hit a point where the incremental additions of powder do not result in a incremental increase in velocity. I have noticed increased pressure signs at this point sometimes as well

What I can say is that I've often seen a fairly uniform increase in velocity with increase in powder charge. Sometimes that continues to a point that I have seen a factor of 2 or even 3 increase. This often is at a point where I'm reaching upper pressure limits. Saying that I have also seen a reduction in increase and even a reducing in velocity with a powder charge increase. This hasn't happened often and I have no real data to support it relationship to pressure limits.

I've done a LOT of loading and testing over the years. When a reloader starts trying to use words like "always" "definitly" etc he is asking for someone to disagree or even prove himself wrong the next time out. Yes I know there are probably "always" like a full case of bullseye in a 30-06 shot through a 25-06 should definitly cause a problem. Yes I would bet money on it. Could I lose that money? There is ALWAYS a chance. If you view "always" as being 100% of the time it is hard for me to use that term when it comes to reloading results. Just to many variables for me to use "Always" very often. Words like "probably" "more than likely" "should" are far easier for this old man.

That's a big 10-4 DJ, I just read the title, not all of the posts... Good work again DJ

I have also noticed large weight differences with some bullets.

The one that sticks in my mind is Wincester Black talon, in 270 caliber.

I had a few that were up to 5 grains in difference for 140 grains bullets.

quote:

Originally posted by Saeed:
I have also noticed large weight differences with some bullets.

The one that sticks in my mind is Wincester Black talon, in 270 caliber.

I had a few that were up to 5 grains in difference for 140 grains bullets.

I may be alone here, but I refuse to ever use anything made by Winchester, primers, powder, bullets, brass.... etc... NEVER EVER

quote:

Originally posted by MHC_TX:
I also use my chronograph to infer pressure limits.

My method is similar to yours in that I use my reloading manuals powder charge weight for a specific bullet as a pressure/velocity guide. When developing a new load I load in 0.5 grain strings, starting below the MAX book pressure and going up to the MAX book pressure (sometimes I even go a little bit above the given MAX book pressure). I then shoot these loads over the chronograph (starting w/ the lowest charge weight load) and record the velocity. What I'm looking for is a linear relationship between the velocity for the increased charge weight (which in my case is 0.5 grains). What I have found is this, in general, when operating below the RED ZONE or Excessive Pressure this linear velocity increase "tends" to hold up, but when I get to a charge weight where I'm getting into high pressure, this linear relationship starts breaking down. For example, say each 0.5 grain in powder is giving me a 20-25 fps increase in measured velocity - if the next higher charge weight load gives me a 80fps increase I infer that I'm now getting into the dangerous area, becaue I have lost that linear trend and things are becoming erratic and I will stop here and not go any higher.

I have also found that different "makes" of bullets with the same weight behave differently, so I will not shoot a Nosler Partition load of xx.x grains, that I have worked up to (with the above method) with a different bullet. I go through the above process for each different bullet.

MHC,

I don't think the guys here will ever agree or agree to disagree on the usefulness of chrony for inferring pressure. We've been there before and done this on many other threads!

But...I would like to affirm your reloading strategy and chronograph procedures! As mine seem similar to your's.

Now, I don't (haven't had to) experiment with much with different bullets as I will pick the bullet for a hunting load first and then work-up a reload using it. I may also work-up a target load using different bullets, but mostly do hunting. Find that one good hunting losd per rifle works well for me and just pick the rifle best for the upcoming task.


I do use the idea of a red zone! Begin shooting factory loads that have the same bullet I want to duplicate over my chrony to establish info on this "red zone". Next I'll pick several powders over the appropriate burn rate range for that caliper. I'll ladder step each powder group on the same as I shoot them across my chrony. This gives 3 valuable pieces of infomation:

1) I can graph and compare the velocity gain per increment in power charge for each powder.

2) I can graph compare the top velocity achieved from one powder to the next. Also, If you assign a burn rate number to the graph, it can point you to other powders that weren't in the first batch.

3) I can look for potential accuray "spots" as the groups on the target get closer.

I've also had some unusual experiences with a slow barrel rifle and some problem componets.

If you would like to compare notes some time PM me.

PS: I reload for 38, 357, 30M1, 270 Win., 7,5x55 Swiss, 7,7x58 Jap., 8x57 Mauser and 9,3x62 Mauser. Near future, plan to add 45 acp and 308 Win.

quote:

Originally posted by djpaintles:

quote:

Originally posted by KenOehler:
If your chronograph readings approach max book velocity, you can assume that you have reached, or have already exceeded, max pressure.
Ken O

MR. Oehler,
Thank you VERY much for responding to this thread.
DJ

Normally I want to separate the wheat from the chaff, but in 1985 I worked on a chaff dispenser for a customer, Tracor.
F15s would shoot chaff out the back to fool missiles.

What does it all mean?
Cut me a P.O. to explain why a Chronograph is not a pressure guide and I will type a page to straighten you out. Otherwise, screw you guys, I'm going home.

There is a lot of excellent info in MHC_TX's post below. At the same time, the word "Pressure" can mean something different depending on how you read his data.

quote:

Originally posted by MHC_TX:
I also use my chronograph to infer pressure limits.

At first glance, this appears to mean he gets an impression that he knows what the Pressure actually is. If that is the intent, then I disagree.

If on the other hand, MHC_TX meant his chronograph "infered" he has reached a point where some unknown Pressure is beginning to show the Erratic Nature of the Powder in use, then I would agree.

quote:

My method is similar to yours in that I use my reloading manuals powder charge weight for a specific bullet as a pressure/velocity guide. When developing a new load I load in 0.5 grain strings, starting below the MAX book pressure and going up to the MAX book pressure (sometimes I even go a little bit above the given MAX book pressure). I then shoot these loads over the chronograph (starting w/ the lowest charge weight load) and record the velocity.

The problem here is thinking a "Specific Pressure" is linked to a Specific Velocity or a Specific amount of Powder. If just doesn't work that way, too many variables to have any clue what the Actual Pressure happens to be.

quote:

What I'm looking for is a linear relationship between the velocity for the increased charge weight (which in my case is 0.5 grains). What I have found is this, in general, when operating below the RED ZONE or Excessive Pressure this linear velocity increase "tends" to hold up, but when I get to a charge weight where I'm getting into high pressure, this linear relationship starts breaking down. For example, say each 0.5 grain in powder is giving me a 20-25 fps increase in measured velocity - if the next higher charge weight load gives me a 80fps increase I infer that I'm now getting into the dangerous area, becaue I have lost that linear trend and things are becoming erratic and I will stop here and not go any higher.

There is a lot of good info in this paragraph. Looking for the point where the Powder becomes Erratic is fine - if - you have not already exceeded the SAAMI Max Pressure Limit for the Cartridge. And Velocity alone will not tell you that.

The Powder may become Erratic before you reach the SAAMI Max for that Cartridge, which means if you are following MHC_TX's description, you will STOP adding Powder hopefully before you have a Ka-Boom. "Hopefully", because once the Powder becomes Erratic you just never know what it will do.

And another bad situation is when you only see the Erratic nature of the Powder after you have exceeded the SAAMI Safe Max Pressure level. Just because the Velocity is below what is shown in a Manual does not necessarily mean you are at a Safe Pressure Level.

quote:

I have also found that different "makes" of bullets with the same weight behave differently, so I will not shoot a Nosler Partition load of xx.x grains, that I have worked up to (with the above method) with a different bullet. I go through the above process for each different bullet.

Excellent input and right on the nose.

quote:

Originally posted by RaySendero:
I don't think the guys here will ever agree or agree to disagree on the usefulness of chrony for inferring pressure.

Hey Ray, I've already "agreed" a chronograph dosen't tell a person anything about Pressure.