What on earth happened?

[Death from Afar]

Due to restrictions at a range I frequent, I purchased a Beretta Storm 9mm carbine, mainly for a range toy ( we cant use full powered rifles on this range).

Anyway, was shooting away. I guess I fired about 100 shots over a 45 minute period. Importantly, the barrel was hot but not smoldering.

About 7 shots into a string the gun went brrt for two rounds, that is, it felt like it had gone automatic, briefly.

Hmm..went I , thinking maybe i was a bit faster on the trigger than thought.

Anyway, when i picked up the brass I saw a case which had been "fired" but with no firing pin indentation. I "tested" the case by "firing" it, to see if the primer had been spent. It had.

The only thing I can think of is a cook off- but the carbine was no where near hot enough to do that. The ammo was reloads- 125 Berry bullet, with VV 320 powder and WW primers.

What do you think?

 

[Emerson Biggies]

Good question. Even with hot guns, cookoffs take time to happen. If it was a cookoff, why did the disconnector not lock up the action on the autoloaded round after the cookoff?
The mystery to me is the un-dented primer. The undented one sounds like some kind of a slam fire due to a high primer.
Or: congratulations you now own a full automatic!

 

[AK103K]

If there were no indentation in the primer, and the gun was in fact "hot", it sounds like it could be a cook off.

But 100 rounds over 45 minutes isnt anything thats going to make the gun anywhere near "hot", so I doubt that was the case. Ive shot multiple mags in closed bolt, full auto guns in just minutes, and they were HOT, and things never cooked off.

My guess would be you had some sort of over sensitive primer, and the gun "slammed" as the bolt went home.

The disconnector should have nothing to do with anything if it were a cook off (or even over sensitive primers). The hammer would have remained set but the bolt would still run.

ETA: I reread and see they were WW primers. I bring this up because I had issues with them in my one AR (it had a suppressor attached) with my reloads, and having it run on in "bursts" a couple of times. I did have primer strikes in the primers, but they were light. The AR's have floating firing pins, and I believe they were slam firing.

I wondered if the suppressor was causing an over gas condition that might have made the gun cycle harder, and if the primers were sensitive, if that wasnt the cause.

Funny this came up now, as I just loaded up about 50 rounds using the same primers this morning, as I just ran out of the CCI's I normally use, and I figured Id try it again and see if it happens again, this time in a different gun, with and without the suppressor. Let you know later today.

 

[AK103K]

Well, 57 rounds fired, with and without the suppressor. No problems and everything ran fine.

It was a different gun (PSA kit gun), so now Ill have to try the Armalite again and see what happens. Not that Ive ever had an issue with it, up until I used those primers.

 

[Death from Afar]

Thanks Guys- I was running a suppressor as well, so maybe the "can" is making the bolt cycle a bit harder?

I tried to repeat the performance last night and no luck- so I think the slam fire is the most likely culprit- perhaps there was some tumbler media left in the pocket.

Nice gun the Storm carbine- I like my guns like my coffee- black and overpriced.