plastic flow of primer material

[Noobie]

Firing a different brand of new factory ammo in his rifle could determine if the rifle was at fault, but that could be very dangerous if the rifle is defective.
Was going to suggest firing the ammo in a different rifle, but that could be very dangerous if the ammo is defective.
It is also possible that both are defective.

 

[Laelkhunter]

Firing a different brand of new factory ammo in his rifle could determine if the rifle was at fault, but that could be very dangerous if the rifle is defective.
Was going to suggest firing the ammo in a different rifle, but that could be very dangerous if the ammo is defective.
It is also possible that both are defective.

Good idea. Try shooting a different brand of factory ammo to see if the problem persists.

 

[Hard H2O]

I have stopped using Federal brass at all for my reloading. The older stuff was fine, but this new stuff is simply too soft in the primer pocket. I fired some factory Federal 300WM and then went to prime the empty cases. The primers seated way too easy; the primers felt loose in the pockets. I discarded the whole batch. I'm pretty sure I would have had primer "jumps" when firing after reloading. I had a similar problem with .308 about a year ago. Try some different brand factory ammo / brass. Just my two cents worth.

When I first got my Savage Model 11 in .300 WSM I took some factory Federal to the range to shoot and so I would have brass for reloading. Federal is local to me so I usually shoot their offerings in factory fodder.

Shot fine but the first rounds I seated primers in the primers just fell right out.

After that I avoid Federal cases for reloading.

 

[Lenny Foffa]

HI all, I do not mean to Hi jack this thread, but Natchez has a hazmat free deal on right now. I just purchased 3 pounds of H 4831SC and by using code FH231211, the $22.00 Hazmat fee was removed. They have that powder in 1 pound and 8 pound containers. Just thought some of you might want to know.

 

[orkan]

Dudes need to stop buying 1lb containers of powder. lol

Even with something as tiny as a 6BRA... you can only get a couple hundred rounds out of a pound of powder.

Even with a .243win barrel eater... you'd need at least 1000rnds (800 at minimum) to take the barrel out... which would take about 6lbs of powder.

Why not just buy 8lbs of any powder you're interested in?

The fact that 1lb containers even exist, other than testing, is an ever-present reminder of just how few rounds people fire in a typical year.

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[Tiny Tim]

Dudes need to stop buying 1lb containers of powder. lol

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One of those is more convenient than an 8 pounder on the bench! Lol

 

[Mark37082]

Brisance is not how you describe the softness of the primer cup. Brisance is the "type" of explosion, or characteristic of the explosive properties. In that way, I can confirm that federal primers are "hotter" than most all of the rest. Brisance, being most aptly used to describe how "hot" a primer is.

However, this has nothing to do with the softness or mailability of the cups. Brisance has nothing to do with that, with the exception of what the result of the brisance has on the material itself. Standard physics applies, that a uniform shockwave generated across a shorter time period will obviously deform it's container to a greater degree than a equal shockwave generated over a longer time. Massive over-simplification there... but again to reiterate that brisance has nothing to do with the mailability of the cups themselves.

https://www.lanl.gov/museum/discover/_docs/high-explosive.pdf

Regarding pressure signs themselves, my article from many years ago still holds relevance:

Understanding Pressure :: Primal Rights, Inc

Reading pressure is a required skill that all shooters must have. Whether you are shooting factory ammunition or your own handloads, you absolutely must be able to detect and interpret pressure signs on your fired brass.

www.primalrights.com

Most shooters will find the information therein to be of interest.


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Greg - Your article was a great read. Very well written and illustrated. Too many people like to push the limits of a cartridge design to achieve some bragging rights on velocity IMO. It takes a skilled eye and feel to determine when you may be reaching the danger zone on some rifles. Pressure spikes can sometimes be encountered in very small increases in powder charges.

Thanks for sharing.

 

[Hugnot]

Mr. Catbrain did not provide photos of the situation, so my conclusions are sort of fuzzy.

Looking at the Federal SDS for primers the entire primer was analyzed by weight including brass cup, anvil - alloy of copper & zinc. The tiny amount of nickel was included. The explosive mixture was lead styphnate with barium (oxidizer) & antimony sulfide (fuel)- this stuff was included in the SDS. A tiny amount of Nitrocellulose & Nitroglycerin was included for some reason that I expect was to include residue from double base smokeless powder blasted into the primer and included with the SDS analysis. Combining nitroglycerin with lead styphnate would be a disaster because of the huge difference in brisance/explosive velocities. I would not want to be near a brick of primers containing NG - nasty stuff having big "shattering" explosive effects.

Impulse is the term used to describe the duration of a force applied on an object, the longer the time the less effect. NG would make for a real frisky primer by shortening the force applied duration (commonly measured by area under curve described by pressure vs time). Hurts less to be pounded on with a fat boxing training glove vs. a light glove.

Stuff happens, my guess is the factory 7 mag round was head-spaced on the belt dimension that was or should have been easily maintained. Was the primer extruded? If so, the brass in the primer cup might have been inadequately work hardened - just guessing - not enough info. Factory ammo recalls happen.

Safety Recall Notice for 28 Nosler 175gr AccuBond Long-Range Trophy Grade Ammunition

 

[ajkellerusmc]

I have stopped using Federal brass at all for my reloading. The older stuff was fine, but this new stuff is simply too soft in the primer pocket. I fired some factory Federal 300WM and then went to prime the empty cases. The primers seated way too easy; the primers felt loose in the pockets. I discarded the whole batch. I'm pretty sure I would have had primer "jumps" when firing after reloading. I had a similar problem with .308 about a year ago. Try some different brand factory ammo / brass. Just my two cents worth.

I stopped using federal rifle brass decades ago because of soft primer pockets. I scrap any federal brass that I come across. In my opinion it is not suitable for reloading.

 

[ajkellerusmc]

Federal cases have been of the soft side for over 30 years. About 1990 two Federal engineers stopped by Camp Perry and I got introduced to them and I asked them why their cases were so soft and they said it was a cost of production savings. The more brass is moved in case forming the harder it gets. The said they used less steps to cut down on production costs.
In their 308 cases the military teams were using we picked them up,loaded them two more times and left them laying.

Now I ran tests using Lake City 7.62 Match cases and loaded them about 90 times and they were still good. I have a LC 65 30.06 case I have loaded 157 times and it still has a snug primer pocket.

I have seen similar in some Lapua 30.06 cases and had several primers fall out of fired cases when bolt was opened.

Hmm, 157 times should make it into the Guinness book of world records!

 

[fta0303]

I think 2 factors could be at play in the OP's case.

- Federal primers are softer than virtually all the rest. There is a metric called 'brisance' for this.

- In order to feed and function in every chamber out there, factory ammo is sized to minimum spec. In many instances this can result in excessive headspace - .010" is not uncommon.

When the cartridge fits loose in the chamber, it *can* accelerate back toward the bolt upon ignition and the added inertia *does* effect deformation.

Brisance is a measure of the primer's combustability, not the softness of its cup.

 

[randy86314]

Good discussion. I viewed the report from Primal Rights several years ago.

For

Catbrain

: Do you have some pics of the fired cases, before decapping?
Also, have you tried different primers, that might fit tighter in the pockets?
Federal brass might be soft, but it works OK for the first shot

 

[memtb]

Could the material seen and appearing to be plastic……some sort of "sealant" on the primer? memtb

 

[bonie]

I have stopped using Federal brass at all for my reloading. The older stuff was fine, but this new stuff is simply too soft in the primer pocket. I fired some factory Federal 300WM and then went to prime the empty cases. The primers seated way too easy; the primers felt loose in the pockets. I discarded the whole batch. I'm pretty sure I would have had primer "jumps" when firing after reloading. I had a similar problem with .308 about a year ago. Try some different brand factory ammo / brass. Just my two cents worth.

try primer sealer before you prime. I've done this with no blow out. I have old FC cases in 300WSM with many firings when there is little resistance, I just seal the primer pockets.