quote:

Originally posted by jackfish:
Looks like the ballistics guru has shown he knows much less than he lets on. It is basic ballistics that an increase in velocity corresponds with an increase in pressure. ....

If jackfish is correct the way he has stated it, then it should be True in all situations and I'd be Totally WRONG-O! Of course if I could provide irrefutable Data that shows jackfish is wrong(as usual) then he would appear to know much MUCH less than he believes..., and makes himself out to be the North end of a South bound Horse. Would that be possible???

So, we go to the good old Hodgdon #26, page 356 concerning Loads for a regular old 30-06 with a 150gr bullet and discover the following mixed in amongst the various MAX Loads:

H414 at 3043fps = 48,7kpsi This is the Fastest Velocity shown and note the rather mild Pressure.

H380 at 2921fps = 50,5kpsi
H4895 at 2932fps = 51kpsi
H322 at 2720fps = 50,7kpsi

Huuuummmm, three irrefutable examples which show the exact opposite of what our amazing jackfish claimed. Imagine that!
-----

Hey IceMan, This is indeed a good thread for you to learn from. You have the option to believe that either Velocity tells you everything you need to know about Pressure(which is totally WRONG), or that a chronograph has flim-flammed a lot of folks into incorrect conclusions.

Excellent chance to see who is right and who is Full-of-Beans.

Best of luck to you.

quote:

It is also well known to most with even a rudimentary knowledge of ballistics that given appropriate loads powders with faster burning rates can produce more velocity with less powder than powders with relatively slower burning rates.

Jackfish, can you point out an example of this?

Here are a few quotes from Ken Oehler, maybe he can explain things better than I can:

quote:

Originally Posted By: KenOehler

Loading to get the book velocities is no guarantee regarding pressures. Getting the book velocities might tend to imply that you had close to book pressures, but there is no guarantee. You must have enough pressure to get the velocity, but getting the expected velocity does not mean the pressures behaved. On the other hand, exceeding book velocities is a guarantee that you exceeded book pressures.

My opinion is that pressures in the 70 -75 Kpsi range can be generated either operating within published loads with a very "tight" barrel, or operating slightly outside published loads with a "normal" barrel. We've fitted strain gages to many barrels in which the user has already worked up loads with the conservative method of increasing charge until he sees "pressure signs" and then backing off a little bit. These load/gun combos usually indicate in the 70-75K psi range or approximately midway beetween "max average pressure" and "proof pressure".
We've seen sufficient variation between individual barrels to realize that just staying within loading manual ranges is not an absolute guarantee of modest pressure.

Operating in the 70-75Kpsi range may be relatively safe, but you must recognize that you've removed a significant part of the safety margin put into place by the manufacturer. A minor change of components could easily bump the pressure well into the proof range.

I'll just throw out the following:

1. Most loads that I've seen developed to "just below obvious pressure signs" have shown 70K - 75K psi when tested.

Having had the opportunity to examine many cases after firing in instrumented guns and barrels (copper, conformal, and strain gage), I have totally lost confidence in my being able to reliably estimate even maximum pressure by feel or examining fired cases. .............................................

For a new reloader who might not know, Ken Oehler is one of the most respected ballisticians of our era. He's manufactured many of the chronographs and pressure testing equipment used both by individual owners and manufacturers. When he talks about ballistics smart people listen. If one of the most experienced ballisticians in history with access to the most accurate pressure testing equipment ever made be able to learn to tell pressure by examining fired cases, how in the world can an individual reloader with no access to pressure equipement (like HC) think they they can?

Sorry HC but if Ken Oehler can't determine pressure by examining cases, I don't think you can either.

To the new reloader let me give some simple advice.

1. Buy a couple good reloading manuals
2. Buy a chronograph
3. Don't exceed the listed powder charges in the manuals.
4. Quit when your velocity matches or exceeds the velocities with the same components you see in the manuals.

Pretty simple steps but it's amazing how many people think that they are smarter than all the ballisticians who write the manuals and exceed the recommended powder charges.........................................DJ

" H414 at 3043 = 48,7kpsi This is the Fastest Velocity shown and note the rather mild Pressure.

H380 at 2921 = 50,5kpsi
H4895 at 2932 = 51kpsi
H322 at 2720 = 50,7kpsi

Huuuummmm, three irrefutable examples which show the exact opposite of what our amazing jackfish claimed. Imagine that! "


The assumption from this is that though all have about the same velocity but pressures differ that velocity tells us nothing about pressure..... right !

Nooooo !

Wrong because if we care to look beyond our beloved dummied down Speer Load manual we see that the relationship between load mass, propellant type, expansion ratio, projectile sectional density and finally projectile velocity is not linear or by any means simple !

It would appear that we have a problem with comprehension:

So for clarity I am going to repeat again !

" The modern gun/ rifle operates from the premise that we cause the combustion of a known mass of a certain solid granular energetic propellant in a chamber barrel system of known internal and spatial dimension and that that mass of propellant is converted to a mass of gas, byproducts and heat and that pressure of a specific value is exerted over time ( the specific impulse) by the gas mass on the base of a bullet with certain sectional density and that bullet in turn is accelerated to a specific velocity. "

The implication of this statement does not imply that if you get 2900 fps from one powder and load @ a certain pressure value it is going to equate to the same pressure value when the same velocity is attained in the next load with another powder !

Apples may be red, tomatoes may be red, that does not mean that apples = tomatoes.

quote:

Originally posted by Ackley Improved User:

quote:

Originally posted by Ackley Improved User:

quote:

Measure the case head after firing for anything more than nominal expansion, and carefully feel for normal pressure to re-seat the primers in previously fired cases. If the primer pocket starts to lose its tension on the primer within three or four firings, then you should be reducing your charge.

Stonecreek,

I certainly agree that "feeling" the finger pressure during the primer re-seating process is very helpful in gaging PSI. I note you believe that "loosening" prockets within 3 to 4 reloadings is an indication of too much pressure, but I ask why do you say 3 to 4. And, can I get you to dilate a bit on what is significant "loosening?" I have my criteria, which I'd like to share, but after you weigh in on this important subject. Regards, AIU

Stonecreek, I'm wondering if I can get you to address my question. Regards, AIU

Sorry, AIU, I missed your post the first time.

"Three or four" loadings is a very arbitrary and subjective number to regard as "acceptable" before finding loosened primer pockets, and I consider it a minimum. If a primer will stay in place with the same load three to four times in a row, then it is not generating pressure which is potentially dangerous (in that particular rifle.) Most of us would like our brass to last more than a few loadings, so a "sustainable" load would not loosen a primer pocket at all, or at least not until after the brass had become so work-hardened by multiple loadings that it failed with a split neck or some such.

What constitutes "loosening" is also subjective. Certainly an experienced reloader grows accustomed to the feel of a properly snug pocket when seating a primer with at thumb tool. I'm sure that if someone created a tool to measure primer seating pressure in PSI that there would be a reasonable measure that you could use as a benchmark, but I have no idea off the top of my head what that figure would be. Also, primer seating pressure varies with the brand of primer. I find WW unplated primers to seat much more easily than CCI, which in turn seem to seat more easily than Federals.

So, all of this is rather vague and subjective, but when your primer more or less falls into place with the slightest of seating pressure, you know that the chamber pressure of the previous load in that case was unsustainable, which means it is also on the verge of dangerous.

What's your take on it?

Ok Vapodog, you guys seem to have great information, but i have a question? How does a newer reloader like myself figure out the correct powder burn rate for a given cartridge (for shits and grins i'll say .308)for the volume expansion as the bullet moves down the barrel, When a reloading manual may list 10 different powders for a given bullet all of varying burn rates? Which one do i choose? I do know that in Quickload if you state your barrel length and all your info, It will in turn give you a good guestimate of percentage of powder burned. Am i on the right path with that? For the record i chose Reloader 15 (They say it's stable in all weather and consistant from batch to batch and accurate) for my first .308 loads and i also have IMR 4064(time tested standby). I am educated and very technically oriented so let er fly, i can grasp it. By the way i have quickload 3.0 and a shooters Alpha chrony is on the way. (Sidenote! ALF is funny as hell!)

The most important sign is primers falling out of a fired case.

quote:

Ok Vapodog, i have a question? How does a newer reloader like myself figure out the correct powder burn rate for a given cartridge

As a newbie the best advice is to use the powder that your loading manual shows to deliver the best velocity in their tests.

It may not be that way for you but it's a darn good place to start.

After a time and some confidence built in reloading you can branch out.....but play it safe....keep to the manuals.....use the best two or three powders the manual shows to generate the best performance and bear in mind that accuracy will eventually trump velocity...

It's a big wide and challenging ball game and a lot of frustration and fun.

Go have a ball!

.

Thanks all that replied to this, i got waaay more than i bargained for but thats good stuff! I will take what i have learned and apply it well. I am of a firm belief that a book does not hold all the answers, The old timers who have been there do!I'm sure you havn't heard the last of my questions.

Hey DJ, Unlike a lot of people, I do have a lot of experience with Pressure Devices and Strain Gauges. I know their weaknesses and limitations. And as difficult as it may seem to believe, I ALWAYS agree with about 95-98% of what Dr. Oehler says - or implies. But, due to my first-hand experience I have no problem at all questioning Dr. Oehler's comments and disagreeing when his comments can be misleading and when he has an agenda of "Selling" something. He is a great Salesman.

quote:

Originally Posted By: KenOehler

Loading to get the book velocities is no guarantee regarding pressures. Getting the book velocities might tend to imply that you had close to book pressures, but there is no guarantee. You must have enough pressure to get the velocity, but getting the expected velocity does not mean the pressures behaved. On the other hand, exceeding book velocities is a guarantee that you exceeded book pressures.

That seems to indicate "ALL Barrels are the same", which I know to be a bunch of bologna. Some are Fast and some are Slow, with a minor few that look about the same. I'll guess you know that to be the truth.

What is of a high importance and is not said in that statement is a reference to a Correction Factor. Without having a Correction Factor, then Dr. Oehlers comment is misleading.

quote:

My opinion is that pressures in the 70 -75 Kpsi range can be generated either operating within published loads with a very "tight" barrel, or operating slightly outside published loads with a "normal" barrel. We've fitted strain gages to many barrels in which the user has already worked up loads with the conservative method of increasing charge until he sees "pressure signs" and then backing off a little bit. These load/gun combos usually indicate in the 70-75K psi range or approximately midway beetween "max average pressure" and "proof pressure".

I'll add that his comments are based on an actual Calibrated Pressure System, found in a controlled environment Lab where a Correction Factor has been established. Not based on a Chronograph alone.

quote:

We've seen sufficient variation between individual barrels to realize that just staying within loading manual ranges is not an absolute guarantee of modest pressure.

Here Dr. Oehler is in complete agreement with ALL of my previous posts concerning Pressure. Good for him.

quote:

Operating in the 70-75Kpsi range may be relatively safe, but you must recognize that you've removed a significant part of the safety margin put into place by the manufacturer. A minor change of components could easily bump the pressure well into the proof range.

The old "straddle the fence" so he dose not hurt anyone's feelings. Basically, it is operating at too high of a Pressure. You end up with short case life, cumulative metal fatigue with your firearm and you are recognized as a Rookie Reloader.

quote:

I'll just throw out the following:

1. Most loads that I've seen developed to "just below obvious pressure signs" have shown 70K - 75K psi when tested.

That appears to be a repeat of the above.

quote:

Having had the opportunity to examine many cases after firing in instrumented guns and barrels (copper, conformal, and strain gage), I have totally lost confidence in my being able to reliably estimate even maximum pressure by feel or examining fired cases.

I agree! Since he did not say so, I'll include you can't tell spit about the Pressure from the Velocity. And the ONLY totally SAFE way to know anything about Pressure is by using good-old, never-fail, always-reliable, relatively-inexpensive, always-repeatable CHE & PRE.

quote:

For a new reloader who might not know, Ken Oehler is one of the most respected ballisticians of our era. He's manufactured many of the chronographs and pressure testing equipment used both by individual owners and manufacturers. When he talks about ballistics smart people listen. If one of the most experienced ballisticians in history with access to the most accurate pressure testing equipment ever made be able to learn to tell pressure by examining fired cases, how in the world can an individual reloader with no access to pressure equipement (like HC) think they they can?

I agree with most of what you said. However, Dr. Oehler is not in the business of "selling" inexpensive 0.0001" capable Micrometers. He is in the business of selling $$$HIGH$$$ Strain Gauge Systems, because he quit selling Haphazard SGSs after this discussion about Haphazard SGSs.

quote:

Sorry HC but if Ken Oehler can't determine pressure by examining cases, I don't think you can either.

And there Dr.Oehler could actually "learn something". If the Primer Pockets are loose after 1, 2, 3-9 firings, then that particular Load is too HOT - based on nothing but "examining" the Cases. I would imagine that you know that DJ. Of course since it does nothing to help sell a totally worthless(outside a lab) Haphazard SGS, I can see where Dr. Oehler would not mention it.

Dr. Oehler totally avoided mentioning good-old, never-fail, always-reliable, relatively-inexpensive, always-repeatable CHE & PRE. And for the exact same reason - it does not sell any totally worthless(outside a lab) Haphazard SGSs.

quote:

To the new reloader let me give some simple advice.

1. Buy a couple good reloading manuals
2. Buy a chronograph
3. Don't exceed the listed powder charges in the manuals.
4. Quit when your velocity matches or exceeds the velocities with the same components you see in the manuals.

I agree with 50% of your list - 1. & 3.

The problem with #2. is it doesn't tell you anything that can't be either "guesstimated" close enough to work, or can be determined by measuring the Drop Rate on Targets.

The problem with #4. is it can get you in Pressure Problems, if the only thing you go by is Velocity - Dr. Oehler said that in the bulk of his comments that you quoted. So, we either believe Dr. Oehler is correct or to paraphrase one of your above sentences, "If one of the most experienced ballisticians in history with access to the most accurate pressure testing equipment ever made (says you can not be SAFE by using a Manual MAX Load all the time), how in the world can an individual reloader who just quoted him(like DJ) think they they can?

quote:

Pretty simple steps but it's amazing how many people think that they are smarter than all the ballisticians who write the manuals and exceed the recommended powder charges. ...DJ

We totally agree!!!

Hello S-Creek, I agree totally with what you have stated in this thread, but would like to point out something. About 3 to 4 years ago, I bought several bricks of the new blue boxed-gold cupped Winchester primers, while still having appox. 500 of the old style silver cupped Winchesters on hand. I quickly noticed that the newer gold-cupped primers fell into the primer pockets somewhat easier than the old ones did, giving the indication that they are slightly undersized. Being the experimentor I am, I fired them in good quality modern M-70 actions, and had absolutely no problems. I did wear safety glasses when firing though.

I would also like to point out, that most of us reloaders have had case seperations at one time or another, probably when we were starting out. As you know this allows the chamber/bolt to have full pressure bearing. I have never had a gun fail nor blow up. I am in no way advocating using unsafe reloading methods but as is apparent here on this thread, safe pressures vary to a finite degree with each reloader. Again for me the most accurate method of checking for unsafe pressure is ease of bolt lift and ease of case extraction (in a good quality bolt gun).

As far as the reloading manual go, I can't seem to find any data that is consistant with the other except for the Lee data which simply copies existing data. There are a few exceptions of this.

Some photos of high pressure More Photos here .Link

Nice photos! I can see the signs pretty well in those!

quote:

Originally posted by Hot Core:

quote:

Having had the opportunity to examine many cases after firing in instrumented guns and barrels (copper, conformal, and strain gage), I have totally lost confidence in my being able to reliably estimate even maximum pressure by feel or examining fired cases.

I agree! Since he did not say so, I'll include you can't tell spit about the Pressure from the Velocity. And the ONLY totally SAFE way to know anything about Pressure is by using good-old, never-fail, always-reliable, relatively-inexpensive, always-repeatable CHE & PRE.

HC, you're not making sense here. Mr. Oehler is saying that he doesn't feel you can determine pressure by examining cases i.e. Case head expansion and Pressure Ring Expansion yet you say you Agree?


For those of you who haven't heard the discussions before HC and I disagree fundamentally on a couple points. He beleives in "Fast" barrels i.e. barrels that can shoot a couple hundred fps faster than velocities you find in the manuals. He also beleives that CHE and PRE are valid ways of determining pressure.

I argue that Fast barrels don't exist, if you are running 200fps faster than any load you find listed in the manuals you are running at higher pressures. HC had a Ruger that did run higher than normal velocities without showing excessive case head expansion. He did NOT however test that rifle with pressure test equipement.

I'm not saying that CHE and PRE are completely useless but experts like Ken Oehler and others have shown that it's not an accurate indicator of pressure. A lot of the older reloading manuals were developed using this method. Now that the people writing the manuals now have access to pressure test equipment MANY of the loads in the new manuals are much lower because the loads developed with CHE and PRE were TOO HOT and over SAAMI pressure guidelines.

Some of the pictures shown obviously show way too high pressures. If your gun explodes and your barrel fly's 30yds downrange you can be sure your load was too hot . The point is that 90K psi loads are easy to tell by looking at the case but loads in the 70-75K psi range are not. Older methods will show Way Way overpressure loads but not necessarily loads that are in the 70-75k range.


So to the OP. Your choice of RL-15 in the 308 is an excellent one. So is Varget and a couple others. It's an easy round to load for with many fine choices of powders and bullets. But be careful about some of the loads in older manuals! Some of them can be too warm in some rifles. The newer manuals are usually developed using proper pressure test equipment and are more accurate.

Again sorry HC, I know you believe in CHE and PRE but they've been proven to be unreliable by professional ballisticians and statisticians. But I do agree that it can still be a usefull crosscheck - just don't use it as an excuse to load more powder than you see in pressure tested data!.........................DJ

Y'all know who Alan Hall is? Was junior partner when he and Ed Shilen formed Shilen Barrels. Alan designed the DGA action. Ed bought him out and he returned to Alabama. Now builds the Hall actions.

Anyway, he had a deer lease in Texas, and used a 308W. Had a "warm" load that shot lights out. One day he was talking to a Winchester/Olin ballistician and mentioned the load. The guy asked him to send him some to test. No sticky bolt lift or cratered primers, just flat. They tested his loads and found he was right at 80K Psi. Pressure signs are not always evident. Don't be building pipe bombs, we like having you all around. Want a lot more speed, get a larger case in your caliber.

Rich

quote:

About 3 to 4 years ago, I bought several bricks of the new blue boxed-gold cupped Winchester primers, while still having appox. 500 of the old style silver cupped Winchesters on hand. I quickly noticed that the newer gold-cupped primers fell into the primer pockets somewhat easier than the old ones did, giving the indication that they are slightly undersized.

My experience exactly. My assumption is that the cups are identical to the older nickel-plated primers, therefore the difference in diameter is the thickness of the plating.

I haven't had any problems with the "undersized" WW plain brass primers, either. I mostly reserve them for the first loading of new brass where I'm confident that they will fit reasonably snuggly.

Many years ago when I was young and (more) foolish, as well as relatively less economically affluent, I would re-use brass on which the primer pockets were, shall we say, "very" loose (sometimes the primer would fall out before I made it to the range!). Despite this, I never had loose primers leak any gas. They seem to obturate sufficiently to seal the primer pocket.

Still, loosened pockets are a certain indicator of borderline -- if not dangerous -- pressures.

Now, it is true that how much and how quickly primer pockets loosen (and case heads expand) depends on the alloy, hardness, and thickness of the brass. So a load generating X pressure in a "hard headed" case may be fully safe in that case, but the same pressure could theoretically rupture a soft or thin-headed case.

This goes back to the fundamental of chamber pressure for modern turnbolts: The brass case is the weak link and limiting factor. Loads worked up to "maximum" with one case brand/lot should never be assumed to be appropriate in another brand/lot of cases.

Another way of describing a "fast barrel" is a barrel that generates more pressure than an "average" barrel with a given load.

There are no magical "fast barrels".

If a given load shoots faster in one barrel than another of the same length, it is likely generating more pressure. The reasons for this are many, and difficult to determine. If any of you are pleased that you have one of these "fast barrels", try extending the throat and lapping the bore and see how fast it still is. I've never personally done this, but I would bet that the velocity with a known load would drop. The same concepts apply to why a load with moly coated bullets will often generate less velocity than with non-coated bullets.

There is no magic, and there is no free lunch when it comes to ballistics.

Wes

quote:

Originally posted by WESR:

There are no magical "fast barrels".

There is no magic, and there is no free lunch when it comes to ballistics.

Wes

Yup.....another good post!

In response to the post that immediately follows this one - Wasn't done vapodog, sorry. I was trying to combine responses and that happened when I was grabbing your quote. Here you go...

quote:

Originally posted by Hot Core:

quote:

Originally posted by jackfish:
Looks like the ballistics guru has shown he knows much less than he lets on. It is basic ballistics that an increase in velocity corresponds with an increase in pressure. ....

If jackfish is correct the way he has stated it, then it should be True in all situations and I'd be Totally WRONG-O! Of course if I could provide irrefutable Data that shows jackfish is wrong(as usual) then he would appear to know much MUCH less than he believes..., and makes himself out to be the North end of a South bound Horse. Would that be possible???

So, we go to the good old Hodgdon #26, page 356 concerning Loads for a regular old 30-06 with a 150gr bullet and discover the following mixed in amongst the various MAX Loads:

H414 at 3043fps = 48,7kpsi This is the Fastest Velocity shown and note the rather mild Pressure.

H380 at 2921fps = 50,5kpsi
H4895 at 2932fps = 51kpsi
H322 at 2720fps = 50,7kpsi

Huuuummmm, three irrefutable examples which show the exact opposite of what our amazing jackfish claimed. Imagine that!
-----

Hey IceMan, This is indeed a good thread for you to learn from. You have the option to believe that either Velocity tells you everything you need to know about Pressure(which is totally WRONG), or that a chronograph has flim-flammed a lot of folks into incorrect conclusions.

Excellent chance to see who is right and who is Full-of-Beans.

Best of luck to you.

It is quite disingenuous to construe my statement as absolute in an attempt to discredit my premise. I don't think many here thought it was necessary to qualify what I said as I'm sure most understood what was implied. But when someone is wrong they will try to obfuscate the issue. So let me qualify my statement:

Given the same cartridge, powder and components, an increase in velocity corresponds with an increase in pressure.

Correspond is a synonym for correlate. It would seem quite evident that as one works up a load and increases the charge there are corresponding increases in velocity and pressure. Is this evident with every increment of increase? Perhaps not, and you certainly will not see equal increases across the entire range. But there is a correlation between velocity and pressure in the trend from starting load to maximum load to platform destruction. A look at the Hodgdon #27 manual reveals that the start loads for a given cartridge, powder and components have a lower charge, velocity and pressure than the maximum loads. Pretty obvious observation.

quote:

Originally posted by vapodog:

quote:

It is also well known to most with even a rudimentary knowledge of ballistics that given appropriate loads powders with faster burning rates can produce more velocity with less powder than powders with relatively slower burning rates.

Jackfish, can you point out an example of this?

There are many examples in Hodgdon #27 and elsewhere. (# on burn rate chart, powder, charge, velocity)

30-06 150 grain bullet
84. H380 53 grains 2798 fps
92. H4350 56 grains 2792 fps

65. Benchmark 49.5 grains 2944 fps
76. IMR4064 51 grains 2928 fps

30-06 180 grain bullet
87. 760 55.5 grains 2743 fps
101. H4831 60 grains 2710 fps

92. H4350 57.5 grains 2798 fps
101. H4831 60 grains 2710 fps

Hence, given appropriate loads, powders with faster burning rates may produce more velocity with less powder than powders with relatively slower burning rates.

quote:

Originally posted by jackfish:

quote:

Originally posted by vapodog:

quote:

It is also well known to most with even a rudimentary knowledge of ballistics that given appropriate loads powders with faster burning rates can produce more velocity with less powder than powders with relatively slower burning rates.

Jackfish, can you point out an example of this?

highly articulated reply!

quote:

Ignored post by jackfish posted 14 January 2010 00:11

welcome to the list!

I went to work entering my data in quickload 3.0 and for SPEER 110FMJ/47-51 grains reloader 15 this is what it spit out. Speer has 47 listed as min and 51 grains as MAX. The 51 grain load came with a warning as being 6% compressed at 50,872 psi. Is this too much?

quote:

being 6% compressed at 50,872 psi. Is this too much?

sure wouldn't bother me!

quote:

Originally posted by WESR:
If any of you are pleased that you have one of these "fast barrels", try extending the throat and lapping the bore and see how fast it still is. I've never personally done this, but I would bet that the velocity with a known load would drop.

So you are saying that a rough bore helps generate more velocity, and a smooth bore will generate less velocity? Clearly this is backwards.

I think what you are trying to say is that a rough bore creates more pressure with a given load (an assumption that I will agree with). But that additional pressure does not translate into additional velocity. This is just one example of pressure and velocity not being directly related.

Certainly, with all things being equal, a smooth bore will yield higher velocity than a rough bore, and will also generate LOWER pressures. This ain't a free lunch -- just feel the temperature of your barrel if you don't think that some of the powder energy is going somewhere besides into the kinetic energy of the bullet. The more of that energy that goes into heating the barrel (in part due to a rough bore) then the less energy goes into the kinetic energy (velocity) of the bullet.

quote:

Originally posted by vapodog:

quote:

Ignored post by jackfish posted 14 January 2010 00:11

welcome to the list!

Well that was quite juvenile!

Icemanis2, I would STRONGLY recommend that you do NOT use Quickload as your final say in what is safe or unsafe loads. Be SURE and crosscheck what Quickload lists with another manual or two.

Quickload is a useful tool but can be WAY off. I've input parameters from other manuals that list the exact pressure they got and Quickload predicted 20K psi different than what was MEASURED in the other manuals.

It's best to look at as many different sources of data as you can and discount values that are way off what the predominace says.

As far as 51grs of RL-22 and a 110gr bullet in a 308, that data might be right on. I'm just saying to be careful with Quickload and don't use it as your ONLY source of data....................DJ

quote:

HC, you're not making sense here. Mr. Oehler is saying that he doesn't feel you can determine pressure by examining cases i.e. Case head expansion and Pressure Ring Expansion yet you say you Agree?

No DJ, Dr. Ohler said "examining", he did not say taking precise measurements. You are assuming things he did not say.

quote:

... MANY of the loads in the new manuals are much lower because the loads developed with CHE and PRE were TOO HOT and over SAAMI pressure guidelines.

I've never seen that "stated" in any Manual. Have seen Loads reduced because of other things like changes in Twist, but I've never seen that stated anywhere.

I'm not asking this "mean spirited" when I ask, is that something else you have assumed to meet your thoughts on the issue?

Excellent unbiased and accurate comments about the old Ruger 7mmRemMag I had - with the Fast Barrel.

quote:

CHE and PRE but they've been proven to be unreliable by professional ballisticians and statisticians.

I'm not doubting that you actually believe that. However, I've yet to talk to one who has said anything close to that. In fact, the Sierra Tech Line recommends measuring Case Heads to see what the Pressure is doing.

Any idea who these "professional ballisticians and statisticians" happen to be? We know CHE totally destroyed all HSGS credability in this link in a totally unbiased comparison between a Haphazard SGS user and Kelbro, who had not been using CHE for a very long time.

Best of luck to you.

quote:

Originally posted by djpaintles:
Icemanis2, I would STRONGLY recommend that you do NOT use Quickload as your final say in what is safe or unsafe loads. Be SURE and crosscheck what Quickload lists with another manual or two.

Quickload is a useful tool but can be WAY off. ...DJ

Completely agree.

quote:

Originally posted by Hot Core:
You are assuming things he did not say.

You appear to be doing just that as well.

examine
a. To analyze: consider in detail and subject to an analysis in order to discover essential features or meaning
b. To observe carefully or critically; inspect

These definitions obviously suggest measurement.

quote:

Originally posted by icemanls2:
I went to work entering my data in quickload 3.0 and for SPEER 110FMJ/47-51 grains reloader 15 this is what it spit out. Speer has 47 listed as min and 51 grains as MAX. The 51 grain load came with a warning as being 6% compressed at 50,872 psi. Is this too much?

Gentlemen.....this post does indeed cite the Speer Manual as a reference for the data. The fact that quickload somewhat agrees is a bonus but I see that icemanls2 is diligently referencing the manual.....good!

quote:

Originally posted by Hot Core:
I'm not doubting that you actually believe that. However, I've yet to talk to one who has said anything close to that. In fact, the Sierra Tech Line recommends measuring Case Heads to see what the Pressure is doing.

Sorry, that was someone at Sinclair International, not Sierra Bullets Tech Line.

A good thread on case head expansion to judge pressures:

http://www.24hourcampfire.com/...php/topics/2962207/1


.................DJ

quote:

Originally posted by Hot Core:

quote:

HC, you're not making sense here. Mr. Oehler is saying that he doesn't feel you can determine pressure by examining cases i.e. Case head expansion and Pressure Ring Expansion yet you say you Agree?

No DJ, Dr. Ohler said "examining", he did not say taking precise measurements. You are assuming things he did not say.

Uh No. Here's another quote:

quote:

originally from Dr. Ken Oehler

Having made many pressure measurements, and having observed the traditional pressure signs on the shots where pressure was actually measured, I have totally lost confidence in using the traditional pressure signs (including measured case and head expansion) as a safe means of working up loads. Yes, the traditional pressure signs do indicate excessive pressure and they are a certain and definite warning to back off, but many times I've seen the pressure signs appear only after exceeding prudent pressure limits. I regard pressure "measurements" as being uncertain enough; pressure "signs" are really reading the tea leaves.

The previous posters who advocate staying below pressure-tested loads from a reputable manual, and backing off if you see any of the traditional pressure signs or the velocity exceeds either factory or load book levels have my vote.

Here's the whole thread if you want to read it:

http://www.24hourcampfire.com/..._expansi#Post1740619

........................DJ

I have been told by some one I know very well that has worked inside one of the major ballistic labs for over 15 years the same thing Ken Oehler said about being far over pressure before the traditional signs show that you are over pressure. He also quoted the 70-75K psi range before the common signs pop up. A chronograph can be helpful working up a load. If you work a load up in small,"such as .5 grain for a .308 case", you will see a somewhat constant rise in pressure. If you see a large jump on one of your .5 grain steps, it would be advisable to drop down 1- 1.5 grains in this scenario. If you are pushing pressure this hard for a few fps, get a bigger mouse trap, i.e. larger case.

Good Grief! Who started this! LOL



icemanls2,

I think you are beginning to get the picture. Taken one at a time most any of the signs of high pressure could be explained away by something else!

BUT, taken colectively, there's many things that will help tell you when your getting too high.


PS: 243, great pics! Thx

How many of you have ever seen or personally know of a bolt action gun blowing up in someones face with the correct caliber/chamber cartridges???????????
I personally only know of one rifle coming apart but the shooter somehow got a .30 cal. cartidge to go off in a 7mm barrel. Talk about high pressure spikes!!!!
Something else I would like to point out is if there was this exact correlation between pressure and velocity, that some of you have suggested, then you would NOT need anything longer than a 2" barrel. But as most of know with all powders there is a sweet spot in barrel length for each powder. The slower the powder (usually) the longer the barrel needed. This is based on bore/case capacity ratio.

Personally, I am a realist. As long as the bolt lifts without much trouble and the case comes out quickly, and the gun doesn't come apart after I have fired over 500 rounds, the primers don't fall out on the way to the chamber or blow out when fired and spew gas in my eyes, I really don't care if I am getting 100,000 psi. No, I don't get crazy with it, if I see ejector marks then I back off.

I know I will catch HELL for this post, so gentlemen, I stand before you blind folded awaiting your bullets to pierce my heart.......... my so deemed high pressure loads certainly have not done it.

quote:

Originally posted by djpaintles:
Icemanis2, I would STRONGLY recommend that you do NOT use Quickload as your final say in what is safe or unsafe loads.

I would never use a computer program as my only source! It is a source of information for me as well as hornady 3rd edition, Speer 14th edition, Reloaders Digest and a few others combined with the common sense signs of high pressure. The load i entered into quickload comes straight from Speers 14th edition and i wanted to compare as they list 51 grains as MAX and do not denote it as being compressed. I know it is compressed though cause i filled the case and i weigh EVERY charge with RCBS (pact) partner scale and double check it on my beam.

quote:

Originally posted by RaySendero:
Good Grief! Who started this!

Ray, I tried to slow them down about 27 posts ago, but when they get rollin, lol.

quote:

Originally posted by icemanls2:

quote:

Originally posted by RaySendero:
Good Grief! Who started this!

Ray, I tried to slow them down about 27 posts ago, but when they get rollin, lol.

It always becomes a pissing match between those who have nothing to do in the evenings. Can you tell that I have nothing to do in the evenings this week???????????????????????????