"signs of pressure" What are they?

[Pond, James Pond]

Yesterday, I received my first batch of reloading equipment. Basically, it is all the stuff I ordered bar the press and powder measure!

I started reading the bumpf that comes with the different components, specifically the die paperwork, outlining set-up, tuning and basic reloading data.

In the usual warnings it read that I should not start increasing loads toward the maximum load without being able to read pressure signs.

So what are your tell-tale signs to watch for?
(I am loading straight sided magnum cases of .44 and regular .38)

[WWWJD]

Well... if projectiles leave the firearm in any place other than the muzzle... Then you know you went too far.

The ABCs of Reloading << worth having/reading.

Primer flattening, primer cratering, case head separation, splits, stretches (lightning strikes for brass... tehehe).. difficult extraction, poor accuracy, headstamp deformations... There's a bunch.

I think if you stay within the confines of any load in any manual... you're in good shape.. better to compare similar loads from at least a few good references to be sure/get a feel.

[Edward429451]

Sticky extraction is almost always the first sign, with or without primer flattening. There's so many good known loads that you may never see any pressure signs. Especially if you have a decent size barrel that will let you get the velocity without the max loads.

[dab102999]

Youtube is your friend here...look up case stretch/casecrack/primmer flat/head seperation..all those will give u visuals and give u links to other videos.

[Pond, James Pond]

Great stuff!!

Thanks for that input. Best to know your enemy, so that info is gold-dust!!

[Don P]

Like stated stay within the parameters the manual gives for your powder and bullet type and weight and should be good to go without issue.

[hornetguy]

Signs of pressure? The bullet left the barrel, making a loud noise.

Signs of excessive pressure? That's another story.

[WWWJD]

Originally Posted by hornetguy

Signs of pressure? The bullet left the barrel, making a loud noise.

We were all thinking it... Low and behold... Someone says it. Ha!

[RevGeo]

Primers may flatten with absolutely safe loads, but I'm very leary when they crater - a little lip around the firing pin indentation. Sticky extraction is your first definite clue that you need to back off your powder charge a bit.
My old man used to say that maturity in handloading comes about when one realizes that the slider on the scale beam goes both directions.

[math teacher]

Primer cratering may occur even though the pressure is not excessive if the primer cup is soft or the firing pin hole is oversized. Watch for the other signs in conjunction with cratering.

[Edward429451]

If you really want to use primer condition for signs of pressure, I was taught that you save one brass case from each loading so you can line them up and see the progression of primer condition.

[WWWJD]

I can't use cratering for my rifle. Firing pin hole on the bolt face is oversized... everything craters in my rifle.

[serf 'rett]

When I test a series of pistol loads, I mark the base of the brass with different colored markers. After shooting, I collect the brass and put it in a holder where I can compare the primers of each step to the primers of the preceding and following steps. Look for flattening and cratering of primers.

[.284]

Look at the link in the first post from UncleNick.


http://thefiringline.com/forums/showthread.php?t=406649

[mikld]

Primers aren't a reliable for pressure indication. Too many variables; soft cups, large pockets, gun variations. If you shoot a gun and the primers fall out of the brass, you have a high pressure issue (been there, done that). Sticky extraction and case head expansion are prolly the most reliable/most used methods. Case head embossing (when case head is pressed against the bolt/recoil shield enough to flatten or "polish out" the headstamp or impressing bolt markings on the case head) and indententations (extractor and firing pin hole protrusion) are signs of high pressure. I've been reloading for 25+ years and by sticking to published load data, I've very rarely experienced over pressure (I once had an oops! where I had a 3 grain overload of True Blue in a .357 Magnum. Scale problem. Shot 2, opened cylinder to check reason for extra loud report and recoil, and primers fell out of cases). When I was a beginner I loaded near max. (young stud, manly man kinda loads), but soon found out there is little need for hot .44 Magnum loads (most of the dinosaurs are gone outta S. Oregon). I'm more comfortable loading light to mid way for accuracy...

[riverrat38]

I think that the signs of over pressure listed are for magnum level pressures only. If a pressure of 25,000 PSI doesn't cause over pressure signs in a .357 Mag, which would be a light load, why would the same pressure show any signs of over pressure in a 38 Spec, in which case it would way over pressure? I think that the idea that you can look for signs of over pressure in a low pressure caliber like 38 Special is a dangerous one.

rat

[Jammer Six]

I've searched the web and agonized over this very question.

I only reload .45 ACP, a low pressure cartridge, so by the time I have high pressure, I already have a problem.

So I've wanted to see bona-fide, honest to god pictures of what a real life pressure sign looks like, preferably in a low pressure, straight wall pistol cartridge.

I've turned up the light and increased magnification many times, wondering "is that?... or maybe not..."

The more specific and accurate the descriptions, the clearer the photograph, the closer the arrow, the more valuable such a reference would be.

I'm quite certain I don't have the expertise to create such a reference, but putting a real guide on the 'net would be a major step forward in our sport, in my humble opinion.

[Edward429451]

I'm quite certain I don't have the expertise to create such a reference

Hey that's funny! Me either, and isn't it usually the bubbas that document the high pressure signs? lol

[hornetguy]

Because of my shameful lack of a pressure barrel in each caliber I load, I have a tendency to just load up to about 90-95% of the max loads listed in several different manuals. (notice I said I load up to, not start with) If there is a significant discrepancy, I usually will either average the max loads, or just go with the lower of the disagreeing parties for my 90-95%.
I do know that I can try to "mike" the case head for expansion, but I've heard differing amounts of stretch that are "acceptable". I can also look at the primers, before and after firing, to see how much flattening is going on. Too many factors can cause flattening for me to use it exclusively, but, I use it as an indicator. For instance, my Swedish mauser flattens all primers to one extent or another, and usually slightly craters them. I do not load it hot. I really don't load it very warm. My standard load pushes a 140gr Hornady softpoint at about 2625 fps. I use 4350 powder.
I've tried some pretty warm loads in my .22 K-Hornet, just to see what was possible, and have actually had enough case head expansion to loosen the primer pockets, with one or two showing slight primer leakage, with blackening around the primers. Scared me to death.
I immediately dropped back a grain or so.. don't remember the exact load, I think it was with WW296 or H110.

Bottom line is... do NOT exceed the upper loads of any manual. If at all possible, compare data in at least two or three reputable manuals. Most of the really accurate loads are NOT the max loads, anyway. Be smart and slightly conservative with your loading, and you should never have to worry about signs of excessive pressure.

[oldreloader]

"I always felt that if I got to the point where I thought it was time to bury my firearms, it was actually time to pick them up.."


VERY true hornetguy.

[Jammer Six]

Now, there's a point I've wondered about.

If you're working up slowly, and you hit the point that's really accurate, would the fact, by itself, that it's an accurate load ever be a high pressure indicator?

"Yeah, it were shooting half an inch, an then it blew my hand off..."

[Lost Sheep]

Originally Posted by Jammer Six

Now, there's a point I've wondered about.

If you're working up slowly, and you hit the point that's really accurate, would the fact, by itself, that it's an accurate load ever be a high pressure indicator?

"Yeah, it were shooting half an inch, an then it blew my hand off..."

No.

Accuracy (or inaccuracy, either) is not a direct (cause and effect type) indicator one way or another regarding pressure.

Lost Sheep

[krackum]

Shot some Bufalo Bore factory Ammo marked safe for any modern Marlin Lever Action in my Marlin and had some difficult to extract cases. Is difficult to extract always a sign and if so, overpressured factory ammo is scarry.

[Don P]

Gas, bloating and being plain miserable in general. Case split, primer missing. Blown up gun and possible personal injury would be signs of excessive pressure

[Archie]

The 'pressure indicators' of flattened primers, expanded web areas, leaking primers and such are all based on centerfire rifle cartridges running in the 50,000 to 60,000 psi range. The .44 Magnum runs in the 40,000 psi range, .357 Magnum in the 35,000 range and .38 Special in the 15,000 psi range. A flattened primer which 'falls out' of the case in most any handgun round is way over the limit. Bless you my son, the Lord was keeping you intact on that one.

If one follows the loading manuals (and Yes, they do somewhat contradict each other) one will seldom get in too deep. If using a mid range loading manual load and one finds signs of high pressure - like sticky extraction or extra velocity - one needs to stop and review the situation.

I suggest - especially to new reloaders - to buy one box of factory ammunition similar to what you intend to reload and note to one's self the level of recoil, blast and such from the factory ammo. The reloads should give the same sorts of results.

And a chronograph. If one has a chronograph, the results on the chrono should roughly match up to the expectations in the manual.