Gunsmithing Problems with Rifle or Factory Ammo???

[Alpine 338]

See attached pictures, factory ammo, rifle has around 100-rounds through it since new. When it was purchased new 10+ years ago, no issues back then with this ammo. Rifle and ammo have set for a long time. It was brought out today, and this was the result. Ammo was stored in a cool basement. Primers do not show any major signs of any high pressure.

Also of interest, a few rounds of the factory new ammo had split necks

Guessing maybe age hardening of the brass?

Factory ammo, Jamison brass.

This is what Peterson's website says about the 408 CT

Correct Hardness
Sticking in the chamber after firing, neck splits, and case-head separation are all a function of
improper hardness along the casing wall. Casings need to be hardest down at the head. If it isn’t
the correct hardness there it contributes to primers blowing out and or gas leak around the
primer during firing.
Casings need to be softest at the mouth and neck. Otherwise the neck tension can be wrong,
and or the neck will split when the projectile is inserted. In the middle of the tube the hardness
needs to be at a different value to prevent case-head separation and or sticking in the gun after
firing.
Not all casing manufacturers have the equipment or ability to dial up or down the hardness
values at the different locations. But we do. And we did. And our casings don’t have the
problems associated with incorrect hardness.

The other thing that's puzzling, the dimples just behind the shoulder, which weren't there before firing.

Cases stuck in the chamber, and we had to use a cleaning rod to pop them out. Not much resistance, just the extractor wouldn't pull them out.

I measured the base area of the fired rounds, and they grew between 6 and 7.5 thousands from the new case.

 

[308Gunner]

Damn I would definitely not shoot anymore of that ammo, pull down the components and buy some brass. That’s my .02

 

[Paqueo]

Dont shot more of that ammo.
If you are a reloader try to seat those bullets .01" more and check if they are "welded" to the necks. If they are it should be hard to seat them further inside the case and will make some noide breaking that bondage.
You can later dismount them and save bullets and maybe cases after anealling them (if they dont colapse or split the necks in the meanwhile)

 

[Halfnutz]

Could the case dents be from excess oil/lube in the chamber?

 

[TxWelder35]

I’d be checking the chamber for damage after firing those.

 

[smoothy8500]

Improper metallurgy. Remember, 10 years ago we were in the midst of a "panic" similar to the current one resulting in leaky Win primers and "surplus" LC brass that failed? Best to disassemble and scrap the brass as another suggested. You already had 4 cases fail, how many more chances do you want to take?

The other thing that's puzzling, the dimples just behind the shoulder, which weren't there before firing.

Gas pressure leaking forward, or from the neck caused the case to partially collapse at the shoulder.

 

[skl1]

If you were measuring growth in the web of the brass case, it should never grow in diameter by .006 or .0075. When you do case head measurements to estimate pressure, they should be in ten-thousanths (.0001's) of an inch. .0007 would even be high (like over magnum 65k psi pressure).

 

[Frank Green]

Improper metallurgy. Remember, 10 years ago we were in the midst of a "panic" similar to the current one resulting in leaky Win primers and "surplus" LC brass that failed? Best to disassemble and scrap the brass as another suggested. You already had 4 cases fail, how many more chances do you want to take?


Gas pressure leaking forward, or from the neck caused the case to partially collapse at the shoulder.

I've seen plenty of those dimples just behind the case shoulder and the case didn't crack etc...near the base.

I'd check the headspace of the ammo to the gun. If I recall correctly too much headspace will have the same effect in causing those dimples as well. Funny it didn't happen 10 years ago but is happening now.

Cases getting brittle after 10 years and properly stored? Anything is possible but I'll say in my opinion I lean towards no.

I just shot some 220 Swift ammo (new brass) that I loaded 30 years ago....ran like a watch! A local guy was having problems with his Swift....some rounds wouldn't fire, some chambered hard etc...all new brass for him....I told him my guess is his sizing die wasn't set up properly and was causing headspace issues....I made him a shoulder bump gauge.....and yep that's what it was! Now he adjusts his sizing die properly during set up and now he has no problems.

 

[Alpine 338]

Ok, to all concerned. After much research, it looks like Jamison brass was crap. Problems like mine are the norm throughout, including those who were shooting African Safari cartridges to those shooting the big Buffalo cartridges in their Sharps and Rolling Blocks, all with new Jamison brass.

Someone I know, PhD type, who works in a metallurgy lab offered to do a failure analysis, so yesterday I mailed him a couple failed cartridges to play with. I know what the answer will be.

I cleaned the bore and chamber, and metal etching from ruptured cases was minimal, so no worries there.

I suggested to the owner that we pull the bullets, reuse the powder, and reload on new brass that has a proven track record, and he agreed with me.

So we're going to wait on him to purchase brass, dies, a big press, etc., as he doesn't currently reload.

 

[308Gunner]

That is very smart, post an update when you get the new loads going.

 

[1moaoff]

Maybe I'm cautious on this but I wouldn't reuse the powder. Of all the components that can degrade over time brass shouldn't but powder and primers can.

I have shot very very old ammo without incident but I wouldn't pull powder and reuse it.

 

[Alpine 338]

Maybe I'm cautious on this but I wouldn't reuse the powder. Of all the components that can degrade over time brass shouldn't but powder and primers can.

I have shot very very old ammo without incident but I wouldn't pull powder and reuse it.

Just curious why you feel it's Ok to shoot very old ammo (old case, old powder), but not Ok to shoot the same powder in a new case?

I've shot 70+ year old surplus ammo, at distance, and it was still accurate, which told me the powder remained stable. Heat is the worst thing that contributes to powder degrading, and this ammo was stored in a cool basement for the past 10-years the owner has assured me.

 

[Paqueo]

I wouldnt reuse that powder. When powder degrades became acid and react with the case brass. I think that helped with the case ruptures. saw it happen on old ammo/cases

Maybe I'm cautious on this but I wouldn't reuse the powder. Of all the components that can degrade over time brass shouldn't but powder and primers can.

I have shot very very old ammo without incident but I wouldn't pull powder and reuse it.

 

[Frank Green]

I wouldnt reuse that powder. When powder degrades became acid and react with the case brass. I think that helped with the case ruptures. saw it happen on old ammo/cases

The main problem with older powder and primers was with the corrosive powder/primers. Over time it breaks down per say and will not have the same burning characteristics as when it was new/fresh. Even on the mild steel cases that show no signs of corrosion it will eat the cases/corrode from the inside out. Also because the burning characteristics is changing this leads to pressure spikes with the ammo (exceeding the normal max working pressure it was set for).

Dave Emary at Hornady and I found this all to be true when I made a pressure test barrel for 8Kurz (7.92x33mm). I supplied original WW2 ammo and new formed brass and loads that I worked up for testing.

The non corrosive powder/primers shouldn't be causing any problems.

I do feel (from the couple of things I've seen over the last 2 years or so) that some things could be changing with powder but cannot say it's across the board with all powder brands/makes.

Again go back to my post...I just pulled out ammo in 220 Swift that I loaded over 30 years ago in brand new cases and shot it thru a rifle. Zero issues. So off hand pulling the bullet and dumping the powder into another case and loading it up....my opinion is it shouldn't hurt ya.

Maybe only load up like 3 rounds with the pulled bullet and powder and shoot/test them before you do all of them.

 

[Alpine 338]

My plan was to start by measuring powder charges with a sample of let's say 10-ea cases. Then maybe start testing at a grain below the lowest charge rate from that sample lot. And that all depends on h2o capacity of the new replacement case, so all things being equal. We all know that commercial manufactured ammunition can have inconsistent powder charge weights. I have a Satorius scale, and can measure down to 0.002 of a grain.

 

[Paqueo]

Again go back to my post...I just pulled out ammo in 220 Swift that I loaded over 30 years ago in brand new cases and shot it thru a rifle. Zero issues. So off hand pulling the bullet and dumping the powder into another case and loading it up....my opinion is it shouldn't hurt ya.

Maybe only load up like 3 rounds with the pulled bullet and powder and shoot/test them before you do all of them.

I do agree with you. After pulling the bullets he can notice if the powder is severely degraded just by the strong smell. Also if powder is clogged and there was noticeable reaction with the case brass from the inside.

If it looks fine why not try it?