I was doing some load development in my 7mm mag using RL22 and 160 accubonds, I checked a few books and started at 65grs and went past max at 67grs. So my velocity at 65gr was 2843 5 shot average, 65.5 gr shot up to 2990av. could not figure out why? Any Suggestions? Next 66gr back down to 2886 av. and my group shrank to.250" shots, great!Then went a touch over max to 66.5grs and speed was 2933 and it opened up some, next went up to 67grs and my group for 3 shots went into .153" excellent again but the other 2 shots opened a bit, my error I think. I see that most everyone pushes their speed to 3050 alot of times,is it safe for me to go a little higher like to 68 grs of RL22? Have not seen any pressure signs like sticky bolt.My barrel is also 26 inches long and the gun is a Sauer202, What are your experiences with the first situation of a jump of velocity? And is velocity a safe way to gauge if your getting near max? Because book velocity does not match my numbers.
Thank you
Elmer

You are not stating your standard deviations, Extreme spreads, nor the number of shots to get that average.

Averages are just that. Small sample sizes can lead to some very wierd intrepretations.

Probably you are having instrumentation error. Just a little off axis error and your chronograph is going to read an entirely different velocity. I have noticed velocities changing just due to my elbow sliding on the bench. The more you shoot, the more you will see this. You have to shoot across the sensors in the exact same way each time, without having unburnt powder confusing the sensors.

As for pressure being related to velocity, the answer is yes. The more you shoot that cartridge you will build a database. Some of that data base will include blown primers at such and such velocity. When you get those that is proof positive that you have too much pressure. You can use that data point when developing loads with other powders.

I really do not like exceeding published values for my 308, 30-06's. Loading data is very mature in those calibers and when my bullets are going faster than book values, the loads are too hot. And I generally find out when the primer blows.

I have tested maybe a thousand 308 loads with my chronograph. Once I fire a known load, I can compare against the load I am developing. I have a pretty good idea of what velocities will cause trouble. And I stay below them.

Still, some powder combinations will blow primers at disappointing low velocities.

You never get a free lunch. If your velocities are higher than book, your pressures are too.

Pressure and velocity are not linear as far as powder charge is concerned. And most important is that as you get closer to max the pressure rises much faster than velocity.As far as accuracy goes the most accurate is often slightly below max !!

quote:

Originally posted by elmerdeer:
...What are your experiences with the first situation of a jump of velocity?

Hey Elmerdeer, 1. It has the potential to be a WARNING indicator.
2. It could mean the Load was pushed far enough ahead by the initial Firing Pressure that the overall Pressure Curve was actually lowered slightly. Maybe this will happen again at that same Level, and maybe not.
3. Or it could mean you are seeing how "Erratic RL-22 happens to be" in that cartridge.(That is why I no longer use RL Powders.)

quote:

...And is velocity a safe way to gauge if your getting near max? Because book velocity does not match my numbers. ...

Absolutely NOT by Velocity alone. As has been said, there is no direct coorelation of Velocity to Pressure. The reason for this is that the "Shape of the Pressure Curve" varies due to subtle differences in the Chamber/Bore dimensions and Cartridge Component variancess.

It would be extremely rare if the Velocity in your rifle matched ANY Velocity listed in ANY Manual. It could happen, but really should not be used as the "only" determining factor as to when it is proper to STOP dumping in Powder.

A lot of folks mistakenly believe you can just keep dumping in Powder until you reach some arbitrary Velocity listed in a Manual and you will be at a SAFE Pressure level. The problem is that there are situations where that can be True, but also situations where it is not. So, if a person intends to be SAFE, it is not a good idea to base what the Pressure "might be" due to Velocity alone.

The confusion you are experiencing is "why" I'm not a fan of chronographs. They have great potential to mislead people about a Load.

Best of luck to you.

Good info posted in response by the guys above.
Interesting point you make about chronographs Hot Core. I bought a chronograph and have never used it, for reasons you state. I work up loads from minimum powder charges till it hits the accuracy "sweet spot", and stop, and never go over max where pressure becomes an issue. That accuracy "sweet spot" is in all cases except one, well below max. I fine tune the load when I hit the accuracy spot and use it. I never worry about acutual velocity as it is information I could only use for trajectory plots. Here in Michigan, the longest shot at a Deer will be well inside 200 yards, so trajectory plotting is moot. I just can't get interested in knowing if my load shoots 2800 or 2875. I shoot the rifle at 100 yards sighted 1" high and go for it. I know it's not as precise as it could be, but a Deer's vital area isn't small.
For long range varmint shooting, I would actually shoot the distances and find drops from shooting rather than calculating them. I'm just getting lazy in my old age..Grin

Don

Hotcore has it right! Leave the chrono home when working loads. Look for consistant accuracy over a long string of shots. Once the sweet spot is where you want it, then chrono the load to see what you have and leave it at that. I would not be going over max to find it either.
To try and reach some velocity you think you should be getting is very dangerous and to load until you get blown primers is at the top of the stupid list.
A very high pressure load can read a much lower velocity then a normal load, stay away!

If you have a chronograph, by all means USE IT.

Keep in mind when reading Hot Core's posts that he has an agenda, and that no qualified expert agrees with him on chronographs.

The chronograph is one of the best tools available to the handloader -- but it's a tool, and just because it gives you numbers, doesn't mean the numbers are right. You can experience read errors, gas interference, etc.

When working up loads, use the chronograph to establish a baseline to make sure you are "ok" -- like you were doing. Then, shut it off and fine tune your load. HTH, Dutch.

One of the bad things about Cronos (I have and use one) and Reloaders (I am one) is the urge some of us get to get the highest velocities. I’m part of the accuracy first crowd. An accurate round is more important than a fast round. I believe, if you need a faster round than a 30-06… buy one, do not try to overload your 30-06. What seems like a “Warm†load in April may be dangerous in August. Pressure is hard to “estimate†and if you are loading to High pressure signs you could be in for a nasty surprise.

quote:

Originally posted by Dutch:
...When working up loads, use the chronograph to establish a baseline to make sure you are "ok" -- like you were doing. Then, shut it off and fine tune your load. HTH, Dutch.

Follow this "advice(?)" and you have the potential to end up with a firearm that looks like this one.

This is the kind of ignorance that gets people, who have no clue at all about how a chronograph should actually be used, way in over their heads. Obviously dutch doesn't understand how Variances in Chambers, Bores, or individual Components which make up a cartridge, can drastically alter the Pressure Curve.

He is correct that I do have an agenda, and that is pointing out the Fools who post absolute stupidity which can get people hurt. An excellent example of this would be dutch's post.

Hey dutch, I can't help it that Dr. Oehler AGREED with me concerning the Haphazard Strain Gauges, or that he agreed that no rational person believes a conversion from PSI to CUP exists. I do understand your frustration in that Dr. Oehler's words - blew you and denton completely out of the water AGAIN! Or perhaps it should be "as usual".

You trying to kill someone dutch? PITIFUL!!!

Dr Oehler partialy agreed with you, in that there is no absolute calibration for pressure (regardless of methiod), however he strongly disagreed with you on PRE & CHE as being better than a properly applied strain gauge.

Regards the PSI/CUP thing, again you are reading in ONLY what you want to, and ignoring everything else. What Denton posted is a general corralation, not a absolute conversion, but again you are to focused on your agenda to understand the difference.

IOW, lighten up a little, it will help keep your blood pressure down.

quote:

Originally posted by Dutch:


Keep in mind when reading Hot Core's posts that he has an agenda, and that no qualified expert agrees with him on chronographs.

One way to disagree is to be respectful and state your position with it's advantages.

I will do that for you:
1) Hot Core, we love you!
2) Be afraid of increases in velocity and it will cause shaking that will warm the body.
3) Being afraid of increases in velocity and it will cause wimpy loads that allows more shooting at game.

Dutch, can you see how to not be critical of others, but brain storm with what you can add, and let it stand on it's own merits?

You have fear going for you.
You are as good as Al Gore with his global warming and his 2500 agreeing experts!

I like using the chrono as a check against current loading data. If I am getting vel. way over what "book" loads are, it makes me a bit nervous & I'll look into why. If I am getting vel. way under, some other factors may be at work.
My .280 is a consistent 1.5moa w/ just about anything. It will do an honest 1moa w/ several loads. I was not getting vel. I was looking for in the "book" loads using 4350 or RL19, before I started hitting pressure signs. A switch to IMR7828 got me the vel. I was hoping for safely & 1moa accuracy I was looking for. I would have had no idea w/o the chronograph that I was loosing 150fps & getting the same accuracy w/ sim. pressure signs.

The chrono is a valuable tool but to use it to estimate pressure is folly. It can not tell you how accurate a load is either. Low SD's will not guarantee tight groups. Only your rifle can tell you that.

quote:

Originally posted by tnekkcc:
...Dutch, ...brain storm with what you can add, and let it stand on it's own merits? ...

Houston..., we have a problem!

quote:

Originally posted by Hot Core:

quote:

...And is velocity a safe way to gauge if your getting near max? Because book velocity does not match my numbers. ...

Absolutely NOT by Velocity alone. As has been said, there is no direct coorelation of Velocity to Pressure. The reason for this is that the "Shape of the Pressure Curve" varies due to subtle differences in the Chamber/Bore dimensions and Cartridge Component variancess.

It would be extremely rare if the Velocity in your rifle matched ANY Velocity listed in ANY Manual. It could happen, but really should not be used as the "only" determining factor as to when it is proper to STOP dumping in Powder.

A lot of folks mistakenly believe you can just keep dumping in Powder until you reach some arbitrary Velocity listed in a Manual and you will be at a SAFE Pressure level. The problem is that there are situations where that can be True, but also situations where it is not. So, if a person intends to be SAFE, it is not a good idea to base what the Pressure "might be" due to Velocity alone.

The confusion you are experiencing is "why" I'm not a fan of chronographs. They have great potential to mislead people about a Load.

Best of luck to you.

I cannot disagree with Hot core.....MUCH!
But I do disagree some!

While I fully concurr that velocity is not a pressure gauge, I disagree that it isn't a piece of interesting data......and it goes like this!

If one knows that a certain factory load produces 2,700'/sec and when doing the load developement one reaches the 2,700'/sec, then it is an "INDICATION" that he is nearing (or exceeding) the SAAMI max for that round as it's reasonable to assume that the factory is loading to the best performance they can (safely)

To this point I disagree that a chronograph isn't a good piece of loading information. I, personally, think it's excellent information.....but like a lot of data, it must be used in context!

Restated:.....not reaching factory velocity is nearly worthless reloading data as it has no bearing on pressures at all! However, actually reaching factory velocity is an indicator that one may not be far off the max SAAMI pressure as it's unreasonable to conclude that that velocity can be reached by a lot less pressure! Inb other words.....this is a one tailed test. Making it means something and not making it means nothing!

As with a lot of things, data must be put into perspective......and this one is easy to misassess.

I strongly disagree that a chronograph is not a useful tool for reloading data.....just use the data in context!

A cronograph can be helpful in determining if you are close to, or reaching, a given pressure level. The cavet is you need to be useing the same components as the source of the data you are following did.
Say Hodgdon shows cartridge "A" loaded with bullet "B" as reaching 2800 fps with XX gr of powder Z and a CCI primer as giving 60K psi. If we load the same powder, bullet and use the same primer we can be reasonably sure we are in the vacinity of the 60K pressure Hodgdon found once we reach 2800 fps.
We still don`t know exactly the pressure of the load. No one can judge to an exact pressure level from the measurment of velocity, CHE, PRE, recoil, ect. We need a way to measure the pressure itself to do that, otherwise we are only measuring the effect it has on other parts of the puzzle. We do know though that pressure, its curve, and velocity of the bullet are related though. If useing the same components and finding the same velocity result we should be close on the load pressure preformance.

quote:

Originally posted by elmerdeer:
I see that most everyone pushes their speed to 3050 alot of times,is it safe for me to go a little higher like to 68 grs of RL22? Have not seen any pressure signs like sticky bolt.
Elmer

Some people choose to go past book max, others don't. When you said you saw no pressure signs, what were you watching for - other than sticky bolt lift?? Did you check the state of your primer pockets after 1,2 and 3 loads of the 67 grs load?? Did they enlarge?? At what temperature were the tests performed??

It is often you'll start seeing enlarged primer pockets before you see other, obvious pressure signs such a flat primers or stiff bolt lift. If this is the case, you are over. If these tests were not done in the hottest weather you ever intend to shoot the ammo in, you need to factor in increasing temperature and leave a margin for that.

All in all, the safe bet is to stay with a book load which does not give you any pressure signs. Your 67 grs load may be the one, it certainly seems to give you good accuracy. 50-100 fps more is going to mean very little in the field. Staying on the conservative side is going to mean more margin for safety.

- mike

quote:

Originally posted by tnekkcc:

You have fear going for you.

Huh?

Hot Core, please understand that I will not argue, debate, discuss or otherwise entertain you. There is no dispute about the facts, other than in your mind.

Everytime you post your personal opinion about "measuring pressure" by measuring brass having any ability to keep anyone safe, I will post the information people need to keep from being endangered by your advice.

Folks posting on this board are smart enough to look up Dr. Oehler's posts, and Denton's posts, and they will draw their conclusions.

You will have to find someone else to harangue. FWIW, Dutch.

quote:

Originally posted by Dutch:
...Everytime you post your personal opinion about "measuring pressure" by measuring brass having any ability to keep anyone safe,

Hey Dutch, I don't believe I've mentioned that in this thread. Perhaps you are a bit paranoid?

quote:

Folks posting on this board are smart enough to look up Dr. Oehler's posts, and Denton's posts, and they will draw their conclusions.

I think that is an excellent idea.
---

Hey Tailgunner, I've sent you a PM.

quote:

Originally posted by vapodog:
...If one knows that a certain factory load produces 2,700'/sec and when doing the load developement one reaches the 2,700'/sec, then it is an "INDICATION" that he is nearing (or exceeding) the SAAMI max for that round as it's reasonable to assume that the factory is loading to the best performance they can (safely). ..

Hey VapoDog, Are you by chance talking about a 180gr bullet in a typical 30-06? It looks fairly close to 2700fps with a 180gr-er for discussion.

What if the guy using the chronograph is a Beginner and follows Dutch's advice with H322? Can he just keep dumping it in until he hits 2700fps?

quote:

Originally posted by Hot Core:
follows Dutch's advice with H322? Can he just keep dumping it in until he hits 2700fps?

Childish......

quote:

Originally posted by Hot Core:

quote:

Originally posted by vapodog:
...If one knows that a certain factory load produces 2,700'/sec and when doing the load developement one reaches the 2,700'/sec, then it is an "INDICATION" that he is nearing (or exceeding) the SAAMI max for that round as it's reasonable to assume that the factory is loading to the best performance they can (safely). ..

Hey VapoDog, Are you by chance talking about a 180gr bullet in a typical 30-06? It looks fairly close to 2700fps with a 180gr-er for discussion.

What if the guy using the chronograph is a Beginner and follows Dutch's advice with H322? Can he just keep dumping it in until he hits 2700fps?

Hot Core....my post suggested no such thing.

To repeat:.....assuming no other signs of high pressure stop a reloader before reaching factry ballistics, the reloader can reasonably assume that reaching factory ballistics is an indication that his pressure may already be at or over SAAMI specs.

I'm not sure why you insist in thinking we're all a bunch of nincompoops here!

Dutch, calling names will do you no good.
You will have to face the logic sooner or later.
St Peter is going to greet you at the gate, "So Dutch, before you enter, what was that BS about pressure, when you had the brass right there?"


When you are near 60 kpsi, who cares what the pressure is?
The condition of the brass is what counts, not the pressure.

Pressure would be a way of estimating the effect on the brass.

But if you have the brass, who cares what the pressure is?

Assuming of course that you are using a rifle that could take repeated 150 kpsi loads.

quote:

Originally posted by bfrshooter:
Hotcore has it right! Leave the chrono home when working loads. Look for consistant accuracy over a long string of shots. Once the sweet spot is where you want it, then chrono the load to see what you have and leave it at that. I would not be going over max to find it either.
To try and reach some velocity you think you should be getting is very dangerous and to load until you get blown primers is at the top of the stupid list.
A very high pressure load can read a much lower velocity then a normal load, stay away!

id rather take the chrony with me, if you indend on shooting long range then the load your using has to have a consistant velocity, if not at longer ranges you'll have vertical stringing that is unnecessary.

but i wouldnt use the velocity to guage pressure, id much rather look for flat primers and a bolt that you have to take your shoe off to move.

quote:

Originally posted by Ol` Joe:
If useing the same components and finding the same velocity result we should be close on the load pressure preformance.

In my experence, I'm usually 100 to 200 fps down on published figures. So far here no one is admitting the manuals tend to use different gear (guns) than we use, and long barrels which isn't always stated.

I would hate to use a chrony to try to get to some book figures, even using the same components. I think I'll stick to what the rifle and brass are telling me. And we don't want to wait until they shout.

It is very rare to equal any book figures. A tight rifle will sometimes exceed book velocities and that is why there are starting loads, so you can work up carefully. No two guns are alike.
I have never, ever tried for max velocity, prefering to load for the finest accuracy a given gun can give me. Then I will chrono it to see what I have as far as consistancy. Then a load can be tweaked a little. I have never had any animal laugh at me because my bullet was slower then what a book said.
There have been those rifles that would not group until I reached 1/2 gr over max but they were not tight chambered either and velocity was still lower then the book said. No way I was going to push it to make it faster.

quote:

Originally posted by vapodog:
...I'm not sure why you insist in thinking we're all a bunch of nincompoops here!

Hey VapoDog, You are missing the point of my post entirely. I do not believe "you" would keep dumping in the Powder at all. The difference is "you" are an experienced reloader and understand the importance of looking at other Pressure Indicators.

Surely after all these years you realize my questions are typically geared toward protecting the Beginners from mis-leading posts.

So, how about answering the question for those Beginners? Should they just keep dumping in H322 until some arbitrary 2700fps velocity with a generic 180gr bullet in a 30-06 is reached?

How about if the powder is switched to H414 or H4350, just keep dumping it in?

That is what they would do if they follow Dutch's recommendation.

If you want to talk about it, send me a PM with your Phone Number and I'll call you on my dime.
---

A chronograph has the potential to be the most misunderstood and misleading device ever offered to Reloaders. It is clearly evident in posts such as Dutch's that some folks will NEVER understand them.

Hot Core
I once knew a reloader that insisted that his double charged 20 Ga shotshells were totally safe because he claimed that the additional powder would merely blow out the barrel.

I think this is called "blackpowder mentality"

He actually thought the amount of powder recommended by Hodgdon's etc was an economic thing and not related to pressure.....that it was not economical to put more than so much in the shell as this was all the shell could burn without blowing the rest out the barrel.....

I think he was vieing for the Darwin awards!!!!

While I'm 100% behind the effort to help the newbie understand the reloading ideology and praise all that make efforts to explain the procedures and thinking patterns for the new folks here, I'm also of the opinion that some responsibility must fall squarely on their shoulders to fully grasp the consequences of the sport.

I can easily see a newbie (very incorrectly) adding powder until a velocity is reached......but have trouble understanding where he gets the starting load. Does Hodgdon show stating loads of H-332 in the 30-06?

Does the newbie continue adding powder even after he has to beat the action open with a 2X4? Does he not think something is wrong when the new primer does not stay seated?

There comes a time when we realize that some folks are destined to not live long!.....to not have their gun working in one piece.....to see with only one eye.....

As long as folks start with the starting loads published by powder manufacturers and other reputable publishers of loading data and work up, I can see no reason to be overly protective of them......They will learn the same as I did and many others....by reading hundreds of posts and listening to dozens of other reloaders and reading a lot of published data and manuals.

Yes.....someday both you and I might even learn something from them!!!

I see that yet another thread has degenerated into the old HC vs. the world and pressure argument.

The problem is that HC thinks like a lawyer and/or a woman. In order to pass his muster one must include an inordinate number of exceptions and disclaimers, or post such exceedingly specific, detailed information as to be near useless.

Come on, we live in the real world. Arguing about the 1/1000th of 1% probability (not a real number, just making a point dammit!) makes one look rather curmudgeonly...but I guess maybe that's the point for some.

As to the original question, I suspect you are seeing excessive variance in one of two places, both previously mentioned. Either you have bad data from your chrono or you have a very erratic load.

I won't tell you what a fellow loaded behind a 335 gr boolit in a .45 Vaquero with no pressure signs at all. Scared me stupid when he told me. Some of you would think it a perfectly normal load and because extraction and primers were normal, you would go on shooting the load to destruction or adding even more powder until cases stick.
A lesser gun would have been in orbit.
There are times when there are no signs that you are exceeding common sense. The gun will only respond in one way, it will hurt you or kill you!

quote:

Originally posted by vapodog:
Hot Core
I once knew a reloader that insisted that his double charged 20 Ga shotshells were totally safe because he claimed that the additional powder would merely blow out the barrel.

I think this is called "blackpowder mentality"

!

Getting extra powder to blow out the barrel in 9mm works allot better with Power Pistol than AA#5.

Power Pistol will make a huge muzzle flash.
AA#5 will blow the extractor out of the gun.

What does it all mean?
You have to know what you're doing.

I've been using Dr. Oehler's chronographs since '75 for load developement. I wouldn't develope a load without using the chronograph. If you understand the data you are getting and correlate that data as your loads increase you will very quickly know when you get into high pressure (not dangerous, just high). The chronograph also quickly lets you find with the most consistant loads. I have seen many loads that were not consistant group well at 100 yards but very poorly at longer ranges. Conversely I've not seen a consistant load with a good bullet that did not shoot well period.

I use the manuals (I have a lot of them going back numerous years) as a guide, not the gospel. I very seldom (as I suspect the same of most reloaders) use the same componants as listed in the manuals. I've been in this game long enough to know that a change in componants can make a great difference. I also know that shooting the same load in different rifles (barrels) can give considerable differences also. So how many of us, even if we get the same componants as listed in the manual, shoot our loads in the same rifles (barrels) that the makers of the manual did? The answer is obvious, none of us. Ergo I work up loads the old way and use the chronograph to tell me how consistant the load is and it's data gives warning of high pressure. With regards to loading to a maximum working pressure I have equaled velocities published in manuals, I have pressured out at lower velocities and I have exceded published velocities with safe pressures. All shooting done for accuracy also. It is a truism that each rifle is a story unto itself. I load for the rifle, not the manual. I firmly recommend the use of a chronograph.

Larry Gibson

i once used 73grains of VV n160 pushing a 165gr ballistic tip in my 300WSM kimber montana 8400. yep was really stacking the powder in there! it says in the manual 165gr ( although its a swift projectile) 66.8gr as a max charge, thats 6.2grains over max or nearly 10%, hell i didnt even see a flat primer!

now, with a different primer (fed 210 insted of win LR) and 67gr of N160 its doing 3000fps and 1" groups @ 100 which is all it'll do.

a change in primer hardly altered the velocity, so im just assuming they were going 3200fps or so....

By memory, all my full-power loads show some effect on the primer. Factory loads look even worse, usually.

quote:

Originally posted by Larry Gibson:
I've been using Dr. Oehler's chronographs since '75 for load developement. I wouldn't develope a load without using the chronograph. If you understand the data you are getting and correlate that data as your loads increase you will very quickly know when you get into high pressure (not dangerous, just high). The chronograph also quickly lets you find with the most consistant loads. I have seen many loads that were not consistant group well at 100 yards but very poorly at longer ranges. Conversely I've not seen a consistant load with a good bullet that did not shoot well period.

I use the manuals (I have a lot of them going back numerous years) as a guide, not the gospel. I very seldom (as I suspect the same of most reloaders) use the same componants as listed in the manuals. I've been in this game long enough to know that a change in componants can make a great difference. I also know that shooting the same load in different rifles (barrels) can give considerable differences also. So how many of us, even if we get the same componants as listed in the manual, shoot our loads in the same rifles (barrels) that the makers of the manual did? The answer is obvious, none of us. Ergo I work up loads the old way and use the chronograph to tell me how consistant the load is and it's data gives warning of high pressure. With regards to loading to a maximum working pressure I have equaled velocities published in manuals, I have pressured out at lower velocities and I have exceded published velocities with safe pressures. All shooting done for accuracy also. It is a truism that each rifle is a story unto itself. I load for the rifle, not the manual. I firmly recommend the use of a chronograph.

Larry Gibson

How is it that some people can measure pressure and handle it?

And then some people measure pressure and suddenly feel like they have a sanctimonious monopoly on safe load development?

These Oehlers seem to be like fire water; some can handle it and some can't.

Larry seems like a nice guy.
What the hell is going on with Dutch?

Maybe needs and intervention and Oehler re-hab?

quote:

Originally posted by CDH:
I see that yet another thread has degenerated into the old HC vs. the world and pressure argument. ...

If you consider you dutch and tailgunner "the World", then it does appear you would be correct. Otherwise, most folks in the thread are leaning toward the "you can NOT determine what the Pressure is from a Velocity" and of course they would be correct.
-----

Now here is an interesting endorsement for a chronograph:

quote:

Originally posted by dutch:
The chronograph is one of the best tools available to the handloader -- but it's a tool, and just because it gives you numbers, doesn't mean the numbers are right. You can experience read errors, gas interference, etc.

Yes, dutch is correct that it can give you "misleading numbers".

Come to think of it, I do believe dutch has agreed with " me ".
-----

Apparently Tailgunner has been real busy, because I've not gotten a response to my PM. Probably at "The Derby".

I refuse to be dragged down to your level of fool, as you will beat me with your years experience.

quote:

If one knows that a certain factory load produces 2,700'/sec and when doing the load developement one reaches the 2,700'/sec, then it is an "INDICATION" that he is nearing (or exceeding) the SAAMI max for that round as it's reasonable to assume that the factory is loading to the best performance they can (safely)

This would only be true if the powder being used was from the same lot that was in the factory loads, and the load was put up in new, unwork-hardened brass from that same factory lot, and the bullets and primers as well.

Larger quatities of slower powders can and do produce higher velocities at lower pressures even when the cases, primers and bullets are the same, provided enough of the slower powder can be gotten into the case. Dangerous pressures can be easily produced with fast powders long before the maximum potential velocity for a given cartridge and bullet are reached.

One thing you can be sure of is that there is a wider variation in max charges with a 7Mag than almost anything. In some rifles if you never go past book max, your velocity may be lower than a 7x57 or certainly a .280, depending on what book you are using. In the next rifle of the same make you may be near the primer-blowing point. Being careful and using a chronograph will help. As far as the guys who never load max, as they are loading for accuracy, in my experience there is certainly nothing to lead me to believe that a recuced load is any more likely to be accurate than a max load in general. Some cartridges , the .220 Swift in particular almost always in a number of rifles shoots best right at the redline, which is OK as I see no reason to shoot a Swift at .223 velocities, it is a speed cartridge. Some rifles and some loads will shoot better backed off a bit, others will not. I certainly see no reason to shoot a 1 in load at 2700 if I can shoot a .5 load at 2900 safely and sometimes it works out that way. I have only worked with one .257 Wby and it shoots 3 shots in a cloverleaf with 100TSX's at 3670 fps. Anybody want to load it down for accuracy?