I was reading an article by Rick Jamison in latest Shooting Times or Guns and Ammo, and he was testing a .30-06 load that showed absolutely no signs of high pressure at 78,000 psi and very slight signs at 83,000 psi. Ouch! It got me thinking, because I've read numerous articles in gun magazines about looking for signs of pressure, and some articles even stating that if there were no signs of high pressure that the loads are safe. It makes me wonder how many reloaders are loading a little too "hot". Next time your at the range and a guy sets up next to you and says that he just started reloading move over a couple of benches!

That's why "pressure signs" are voodoo. Use the chronograph in conjunction with the reloading manuals or if you have the money and the inclination, a strain guage.

Slowhand,

I wonder how Mr. Jameson got his results!

It would be interesting to know.

I still believe that what constitute a dangerous load and a safe one also depends on the rifle.

We load a lot of ammo here, and I have found that some rifles might take up to several grains of powder more, than another one.

Velocity also seems to vary quite a bit between certain rifles, with the same load.

Just my opinion, but a lot of the "hard bolt lift" signs came (come) from uneven bolt lugs binding up under pressure, so someone with even lug bearing could load to higher pressures with out binding.
Excess headspace, due to pushing the shoulders to far back, will cause a lot of the primer flatening that they used to go by.
Velocities that the "old boys" quoted were strictly guesses on their part "it kicked the snot out of me so it must have been going at least 3400fps" as chronographs were not reliable nor readaly available.
Saeed
There is a company (or 2) here in the states that will test your reloads in a pressure barrel, if your not lucky enugh to have a "in" with a ammo or bullet manfacture.

Saeed. Jamison used a Remington 700 action switch barrel outfit with SAAMI spec test barrels and strain gages with the Oehler M43 PBL. The rounds he did the tests with wer .270 Win., 30-06, 7MM Mag. and .300 Win. Mag.
He shot loads with increasing powder charges until he got signs of pressure. IE stiff bolt opening, ejector marks etc. He reorded the pressure for all the shots past what factory loads produced, and the pressures he got were way out of line. Sure does make one think.
Paul B.

Modern actions are designed to handle such pressure. I conclude that because we have loaded to such pressures for a generation, and I do not personally know of a blowup. I know some have been reported, but I do not believe that it is due to an overload of slow burning powder.

I have, for over 40 years worked up loads by observing signs that I felt were significant. Things like hard bolt lift, short case life, appearance of the case especially as the base might show signs of flowing into the ejector or other. Also, I have had a chronograph since the early 60's, and I accept that there is some correlation between pressure and velocities. I realize that individual rifles seem to get different velocities with similar pressures.

I don't really care what the actual pressure is as long as the signs are acceptable. I have always loaded my rifles hot, and have never had a problem. I started reloading in 1957.

If my bolt lifts easy, the primers are ok, the case life is good, then I don't woprry about pressures.

I think that the technology of today has caused folks to worry about things that are not really that much of a problem, as shown by many people reloading millions of rounds in the last 50 years with little troube.

Pressure is important, but as long as one uses good judgement it is not a problem. Pressure is what makes the bullet fly.

Jerry

Slowhand,
so what do we care if a load has 83,000 psi and no noticeable effects?

What if it had a million psi?
A billion psi?
A trillion psi?

Pressure measurements have less absolute meaning to the advanced hand loader with a strong gun. Pressure has more meaning if you are selling ammo to the public to use in guns loosely categorized as using the same cartridge.

What matters is the effects of pressure. We use pressure measurements to try to map those effects and make safety margins to avoid them. The advanced hand loader can make a very detailed and accurate map of the effects of pressure in his gun. He doesn't care if those effects are at 60 kpsi or 160 kpsi, he backs off the same powder charge for safety margin to make his practical loads in either case.

The problem is when a load is worked up to "maximum" in one rifle then it is shot out of a weaker rifle.

Just as a side note, I did a little experimentation and found I could get the brass to start flowing into the ejector hole just by lightly oiling the chamber. The load was in the middle of the range published by Speer. I was curious about the dry chamber/oily chamber thing. I'm fascinated about how to analyze a sequence of events that happen in a very short period of time. Now I'm wondering if the ejector hole flow can be caused by the impact of the case head, or if the impact causes a pressure spike throughout the inside of the case due to the momentum of the expanding gases.

Hairtrigger,
Could you name some 30-06's that are weak?

I might get one an test it.

Most of the guns I buy are for such testing.

I was not refering only to 3006.

The easiest example I can think of is 4570, old vs new rifles

TWO QUESTIONS:

WHAT DID JAMISON SAY THE POINT OF HIS TESTS WAS?

WHAT DID HE HAVE TO SAY ABOUT THE RESULTS?

Left out of this is accuracy. In all of my reloading, I never get the best accuracy out of max loads as listed in the manuals. My most accurate loads are always around a grain to a grain and a half under the max load. I have loaded the max load and fired them and accuracy went down, sometimes dramatically. I don't imagine the gain in velocity would necessarily lead to improved accuracy.

One more point: The strength of thw action is irrelevant. The weak point is the casing.

Hey SlowHand, I've not bothered reading Jamison's stuff ever since I noticed he had a tendancy to "warm load" his favorite calibers and "cool load" those that weren't when comparing different cartridges - basically biased info.

That said, he has been a strong supporter of chronographs and strain gauges ever since they began giving them to him. I can see where he likes them, since it is quick and easy to read Second Hand Pressure Info from the barrel mounted Strain Gauge.

Without having read the article, I'd venture a guess he made no mention at all of using either Case Head Expansion or Pressure Ring Expansion(the very best Pressure detection method available) in his article. Had he used either method, he would have "STOPPED" long before reaching those extremely high Pressures. And of course that would have killed his article.

...

RogerK: The strength of the action is irrelevant. The weak point is the casing.

Hey Roger, I completely agree that the "case" is the normal weal point. However, the cumulative effects of "Metal Fatigue" created by continuous overloading is a serious issue. Everything seems to be holding together well and all of a sudden Metal Fatigue can allow a catostrophic failure.

I used to buy a good many "used" firearms, but only do it now if I know the original owner and what he shot in it. Generally just stick with new stuff now days.

I see Loads listed at various sites that may "appear to be SAFE" in one persons rifle and then they quote it as, "works well in all rifles of this caliber". Actually, that Load may create a serious Pressure problem in a different rifle.

I measure case head expansion, at the junction of the solid head and case wall. Use a micrometer to four didgits. I stay at or below the figure I get with factory ammo. I believe the factory guys and SAMMI know what they are doing.

When I was younger, and less experienced, I screwed up a couple of rifles. Now I get better accuracy and less gas in my face.

Hot Core, two questions.

If the strain gauge is "second hand" information, what is the case measurement info?

Second, when you say that pressure ring expansion measurements are the best, what do you mean? Most repeatable? Most accurate? Dutch.

In no way meaning to disparage Mr. Jamison however it seems that of late (last few years) he's gotten awful conservative. I've also heard some disagreements as to the accuracy of strain guages. Thats certainly not how they meassure pressure at ballistic labs. As mentioned above I feel confident that the pressure signs I've used for years are safe especially as my reloading habits are to never make a particular round shoot faster than they ought to. Some of Ricks loads are under every manual on the shelf, on the other hand Layne Simpson (who I admire a great deal ) has suggested loads that must take a 10 foot drop tube. Example--have any of you 7.08 reloaders ever tried to get 51 gr of RL19 into a 7.08 case in front of a 140gr bullet? Layne suggested that load as one of his favorite antelope loads, doesn't work for me. Always remember, gun writers are just guys that like to shoot, much like yourself. Two big time gun writers live in my town, it's a small town and you see em at gun shows, gun shops etc. Trust me--their just guys with a neat job. If you spent much time with em some a their ideas you'd agree with some you wouldn't , just like on this forum. Start low, move up slow, trust your results. Your the only one shooting your rifle your responsible for your results.Just my two cents worth---Shoot Safe---montdoug

I think the main point/goal of this "testing" was to sell more magazines.

Hot Core,

quote:

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..the cumulative effects of "Metal Fatigue" created by continuous overloading is a serious issue. Everything seems to be holding together well and all of a sudden Metal Fatigue can allow a catostrophic failure.

---

Metal fatigue from hot loads that don't stretch the action with each shot?
Forces that don't reach the metal's yield point, yet cause metal fatigue?
How is that possible?
I can see metal fatigue if each shot stretched the action and you pounded or bent it back into place, then after engough times [a million in some cases in my text book] then you could get metal fatigue.

[ 04-08-2003, 09:48: Message edited by: Clark ]

I'd put my money on Jamison before I'd believe some of the "experts" in this thread.

That article was for those folks who have to have to most velocity/energy out of every round they fire. Never mind they can't hit the broad side of a barn!! "Man I get 4000 fps faster then factory stuff"!! Who cares!
RogerK
I'm with you on this one- I don't need to push my '06 to get 3400 FPS with a 180 gr bullet! If I'm getting 2700-2800 and it hits were I want it to hit with enough energy to kill what I want it to kill that's what I want. This is all part of the Magnum Craze!! I'll stay chugging along at 2500-3000 Fps and kill just as well as the 4000 fps crowd.

[ 04-08-2003, 22:36: Message edited by: Gunnut45/454 ]

Hot Core---as I mentioned their all just guys. I read a lot of magazines surf a lot of web (I like this site a lot )and then come up with hopefully logical conclusions. I've been reloading since the late 60's the more I do it the more I realize I got a ton to learn, thats why it's such a great hobby. It can be persued at many levels. A guy can make big mistakes putting to much importance on one bit of information he picks up somewhere. A point in fact again picking on Layne Simpson---When Ruger was first bringing out the Hornet I wanted one in the worst old fashion way. I looked every where and they wern't to be found. Finally Layne did an article on one which of course I read. He talked about how neat Ruger rifles are, how neat the caliber is, and showed the results of his tests. 3to 4 inch groups were the best he got with that particular rifle---no where in that article did he have the nerve to say this gun shot like poop! HAVE YOU EVER COUNTED THE RUGER ADDS IN A SHOOTING TIMES? Whats he gonna say? Gun writers have a job, write interesting articles to sell magazines so they can sell advertising---the big money is in the advertising. I don't hold it against them cause I like the articles I learn a lot from them, one of the things I've learned is don't take every thing any of them say at face value. Do you think they pay for all those neat little gizmos they tell you about in the magazines? what do you think a great send off from a respected gun writer like Mr. Jamison is worth to a small company? One of their gizmos free gratis for sure.Gun writer tears up the gizmos in print guess what? no more free little gizmos! With out using names I'll relay a true story. Local gun smith old time benchrester, great rifles. One of the local big name gun writers contacts him and says if this guy builds him a nice rifle-FREE-he'll mention this guy in an up coming article. Great advertising---pretty cheesey! Lots of great info in gun mags but the articles are all written by regular guys sometimes on tight schedules and in a rush. sure don't want to step on toes, just saying carefully worked up info in a specific rifle means more than trustng everything you read or hear.---Shoot Safe---montdoug

"......Second, when you say that pressure ring expansion measurements are the best, what do you mean? Most repeatable? Most accurate? "

Probably not best but, it is one way to get a measurement of relative pressure. It takes the guess work and voodoo out of judging pressures. All you need is a mic. I can afford a mic, not a strain gauge. The amount of the case expanded toward the solid head is a funtion of pressure. The higher the pressure the thicker the brass that can be expanded. Since the case is tapered it will be fatter if the pressure was higher.

Now load some of the same cases with your handload. Measure the expansion. Was it more or less than factory?? If it was less you can add more powder. If it was more you should probably back off. It is not as easy as reading a digital display but, will give you a reliable indication of the relative pressusre of your load.

Now obviously some judgement is in order. I would probaly not exceed factory readings in a hot magnum chambering. Something like a 257 Roberts or a 45-70 can be increased over the factory figures with safety.

Hey montdoug, I completely agree. By the way, if I've not said so before, it is good to see you posting here.

Hey scot, I intended to say it was real nice to see another "Micrometer Guy" on this Board in my last post and forgot(Senior moment).

...

Gotta do some moving the next couple of days, so if you all don't hear from me, it is not because I'm ignoring you.

Best of luck to all you guys.

[ 04-09-2003, 02:01: Message edited by: Hot Core ]

Hot Core---Why don't ya tell us where you live and we'll all come help----YEAH RIGHT!!! Not mocking your plight, just passing on what I got last year when I moved. A lot like work. Please remember if it looks too heavy it probably is. Good luck.---Shoot Safe---montdoug

AGAIN I ASK:

quote:

---

Originally posted by sonofagun:
TWO QUESTIONS:

WHAT DID JAMISON SAY THE POINT OF HIS TESTS WAS?

WHAT DID HE HAVE TO SAY ABOUT THE RESULTS?

---

CAN ANYBODY ENLIGHTEN US?

sonofagun--I just read the article (quickly) and as near as I can tell his point was, you can't use any of the old methods to detect excess pressure ie: sticky bolt, flattened primers, primer material flowing back into the firing pin hole, cause by the time any of these things happen your way over pressure. He tested a .270, 7 mag,.06 and a .300mag. He started low and raised the charge grn at a time till he got pressure signs visable on the case or a sticky bolt at the point he found the first sign his pressures ran from 68,000 psi to 83,000psi measured on his Oehler system 83 via strain gauge, 65,000 being max. I think the point of this, as well as a number of his articles since he got this cursed strain gauge is to convince us all to never trust any thing but the book. He didn't mention measurement at the web which has always been one of my first checks, but all in all it was an interesting article. He was using pressure barrels at minimum sammi most factory guns are .002 to .004 over that , but his test seems thorough. My main problem was and is that I've heard a lot of doubt aimed at strain gauges accuracy. Most of his loads seem to be starting loads in the books and the velocity is usually quite low. He probably knows a lot that I don't but I've never had a pressure problem in worked up loads and I'm comfortable with my loading practices. Food for thought though I might call Sierra tech line and ask them what they think of strain gauges. Hot Core-- Good luck setting up your loading room , that was the worst, didn't know where anything was. Better now though---Shoot Safe---montdoug

montdoug, Liked your replies!! I would love to have the job Rick Jamison has!! Write it, they'll beleive it, and they'll buy the next issue!! GHD

I am fairly new to this sport. I was told by the fellow that got me into it and I read a litle about pressure signs. All my rifles are modern bolts pluss 1 Guide Gun. I always stay within the data, check my primers and watch for a tight extraction. Is that OK for starters?

Hey DickPal, We have been able to load cartridges SAFELY for a little over 100 years now without the need or expense of a chronograph or strain gauges. So, don't get PT Barnumed into thinking you absolutely have to have them to Reload.

They do provide "one more" Pressure Indicator, so if you have access to them, by all means use them.

I prefer Pressure Ring Expansion(PRE) over all other methods simply because it works so well to keep you out of Pressure Problems. All you need is a set of 0.0001" capable Micrometers and a box of Factory ammo to establish a Benchmark. (You can not do this with 0.001" capable Calipers.)

You should be able to find out about it in "Ken Water's Pet Loads" books from Wolfe Publishing. Or in one of Bob Hagel's books. Or scan back through previous posts on this subject. Or start a new thread.

If you are seriously interested in it, I can send you some Files on it in a couple of weeks. I don't have my computer right now, and the Files are on it.

Guys; After trying several of RJs pet/recommended loads several years ago I wouldn't believe a thing he says. Another gunsmith and myself opined that he should be barred from ever writing about loading ever again. Derf

I again agree with HotCore about loading methods as well as what Martindog said. Reloading is not voodoo----!. If aproached in a safe sane manner theres no need to fear death and destruction from accidentally exploding firearms. My biggest mistake was taking someones advice on a good powder to use in a cartrige once when I really didn't think it was the right choice. I was loading a 7.08 with 140grn Sierras. A buddy told me he'd had great luck with AA 2015-BR I shoot that powder in a 6 BR and it's very accurate. I tried his load in the .08 backing off a bit for safety and working up. It was indeed very accurate ( bug holes ), with good velocity( way fast for a 7.08). The one thing I didn't like was it only filled the case about 2/3rds and it seemed like 2015 is just a little on the fast side for the .08. At any rate , I worked up a load that shot very well and I must of shot that load at the range 15 different trips out there and finally trusted it. My problem was our range has a covered bench, and while I was working that load up at summer temps I was in the shade. I'll bet you know where I'm going, we took it antelope hunting to the eastern part of the state ( the hot part ) laid behind a dirt berm for about an hour and a half in the sun as a herd slowly wandered our way. When they got to 200yrds my wife touched one off, goat drops, and as usual as she racks another round I'm going for the fired brass. The primer was gone and the ejector mark looked like a full moon on the back of the case you couldn't read! Not only had I screwed up , I let some one else shoot it! Boy would my wife be cranky with a pirates patch on her right eye. That was a serious lessen for me," DON'T TRY TO MAKE A 7.08 A .280." I have a chrono, instead of trusting it and realizing " There are no free lunches in ballistics " I got caught caught up in my buddies enthusiasm over a magic load and made a huge mistake. Maybe a strain gauge would of seen it comming, I don't know. There were no excessive signs of pressure right up till we cooked it in the sun, and that includes web meassuring which is one of my favorites too HotCore. Big mistake here was I got greedy, I wanted to much out of the wrong caliber. I do heartily agree with Jamison on one point, if you need the bullet to go faster than it's supposed to get a bigger case! I will assure you that will never happen in my loading room again. I think intermediate reloaders are the ones at the greatest risk .We've gotten over the initial fear of the process and we start to over reach, usually by listening to to many big windys from our buddys and expecting to much. Once we get past that we're way ahead. Too much thinking going on here, now I want a strain gauge, don't tell my wife.---Shoot Safe---montdoug

I read the article and found it quite interesting. The overwhelming majority of handloaders, though, will never have access to the accurate (and expensive) pressure testing equipment that's currently available to ballistic labs. So, what's left? We continue to check for stiff bolt lift, look at primers, look for brass flow into ejector holes, mic for case head expansion, check for loose primer pockets, etc. The chronograph, however, is an ideal tool to help avoid high pressure loads. When we get to the point of diminishing returns, where additional powder raises pressure very quickly, but shows very little in velocity gain, we can be sure that it's time to ease up or back off. Whether or not a particular rifle or brass case will handle more pressure for that particular shot is irrelevant in the long run. A chronograph makes the printed reloading manuals look a little more plausible for the specific components used. If they could show more velocity without publishing data that could be considered dangerous, they would be doing so.

I have been toying with the idea that pressure measurements do not matter for some time, and now I am beginning to toy with the idea that velocity measurements do not matter either.

I AM concerned with the EFFECTS of pressure and velocity, but I am not going to get hung up measurements. The pressure hang ups remind me of a joke; "Why can't [members of my denomination] make love standing up? ....... Because it looks too much like they are dancing."
Translating this to our topic, "Why can't a handloader use any load that works fine in his rifle?....Because there may be too much pressure."
The point is dancing is to be avoided because it might lead to sin, not the other way around. And high pressure loads are to be avoided because they might not work in the handloader's rifle, not the other way around.

For a while I have been overloading pistol cartridges to see what would happen and what the power potential of the cartridge and gun were.

I would work up to where something went wrong that I could not work around, back off a safety margin and call it a maximum load for me. I compared two powder's power potential for that cartridge and bullet by comparing recoil.

I decided that if I could not tell the difference between recoils, there was not enough power difference to matter.

Now I am working up rifle loads for the .223. I am beginning to think that I will compare the effects of velocity on a distant target. If I cannot tell the difference, it does not matter to me.

While this is all very interesting, when I read about situations such as this, I go back to a story related to me by a guy who has a monthly column in one of the big monthly handgun magazines. He told me that the articles we read are only there to seperate the advertisements, period. They really don't have to make a lot of sense, or even be all that interesting. Since that evening, I've taken EVERYTHING I read in the gun rags with a very large grain of salt. I find, usually, much more valuable, and honest, information in this forum, but the laptop doesn't seem to fit too well in the magazine rack next to the toilet.