What caused this?

[JohnAL]

Some may be Berdan but not the Blazers that I have.

 

[Mr. Katanga]

Nope cci primers, hell ive noticed that a lot of the tula pistol steel cases are boxer primed now, ive loaded plenty of those too.

 

[Welldoya]

I once shot some old corroded WWII .45 that my grandfather kept in the shed for 50 years. It split like that. Scared the heck out of me.

 

[rick1967]

Time ago I shot some old 9mm makarov aluminum cased ammo and one case blew in pieces cutting my finger thru the glove. Aluminum age hardens with time and this ammo was at least 12-15 years old.

 

[smithnsig]

Split cases that originate at the case mouth are not usually dangerous. It's the rupture at the base that indicates oob firing as the mouth is still supported. That being said I had a p30 9 mm that had a large chamber. It would reall bulge the brass, and occasionally split aluminum just like the picture.

 

[flyandscuba]

I'm thinking that these were reloaded aluminum cases. Resize them once or twice, then I would expect them to split. I reloaded 45 ACP steel cases decades ago -- and they would also split like that after one or two reloadings.

My commie milsurp 7.62x25mm steel ammo splits cases like that when fired from my PPS43 on the first shooting! I think it is because the legal semi-auto PPS43's are shooting from a closed bolt rather than from an open bolt as intended when the ammo was produced. The indention crimps found in many Tokarev ammo also lends itself to splitting cases upon firing.

 

[steve]

A little more information...
These are Berdan primed I think (two holes)??? It appears as though they split from near the base to mouth. If you look closely at the pics you can see where the split originates by the markings left from the gas exiting near the base of the shell. (I could be wrong!) There were only three people at the range that could have possibly fired these and I talked to one (still trying to contact the other two). He was shooting a Springfield XDS with new (not reloaded) Blazer aluminum ammo so I thought I had found the gun that fired these. What are the odds of three people at the range and more than one shooting aluminum cased Blazer .45? After disassembly, cleaning and inspecting I could see nothing abnormal. I closely inspected the chamber as that was where I thought the problem would be - looks fine? I will take it to the range later and test fire. Any more theories, guesses or suggestions? I appreciate the comments and any more suggestions!

 

[smithnsig]

I'd shoot it with some good brass and inspect
That.