Board:
Yesterday I blew up my sp1
After firing several shots, I pulled the trigger and the dreaded click was heard.  I pulled the charging handle to the rear to eject and feed, and got a double feed.  Pulled the charging handle to the rear and locked the bolt to the rear.  Dropped the mag and the double fed round. Looked inside and there was a round in the chamber.
DON'T DO THE REST OF THIS DRILL.
I then pulled back on the charging handle and allowed it to go about half way to the chamber then released it.   BANG.........
The slam fire split the upper reciever down the centerline below the carrying handle,  blew the shell casing half way out the chamber disallowing the bolt to go all the way forward. Also the bolt will not go completely to the rear and I haven't figgered that out yet.  Ruined the gun, and I got some few little powderburns and abrasions.
Bottom line is:  Don't let the bolt slam forward on an AR, or M1A, style rifle while there is a round in the chamber.  It probably won't slamfire, but if it does, you won't like it.
I had heard of this happening, but had done this drill a couple of times  during my shooting years.  Over 40 years shooting.  Nothing had happened before, so I didn't think much of it.
Learn from the errors of others bretheren.
Yours in shooting,
DVC
Kelly

A slam fire should not destroy your gun! The firing pin cannot protrude from the bolt until it is in it's locked position and the round is fully chambered.

Were you shooting reloaded ammo? It sounds as if you had a primer seated too high. This could cause an out of battery detonation by allowing the bolt face to discharge the primer before the breech is sealed.

Give us some more info on the ammo type....

The "slamfire" in itself is (was) not the core of the problem.

Ponyboy may be on the right trail with the mis-seated primer theory.

The "slamfire" in itself is (was) not the core of the problem.

Ponyboy may be on the right trail with the mis-seated primer theory.

I'm sorry that your gun is toast but glad that you're allright.

Accidents like this make me like the forward assist feature more.

Possibly this slam fire could have been initially caused by a soft primer.  Other responses to other boards have reported that Winchester primers have been the cause of slam fires in the AR style of rifle.  A manufacturing change to make them more sensitive.  I've been loading with winchester primers.  Probably wont be able to determine if the primer was high or if cartridge was not completely seated in the chamber because the whole ass end of the casing is gone.  I looked into the chamber port before allowing the bolt forward, and the cartridge appeared to be seated.  It was too dark in there so see it exactly, or if there was a dent on the primer from the previous strike, or if the primer was in fact a high primer.
Boy what a mess.
Yours in shooting,
DVC
Kelly

Winchester primers- interesting you mention this.

I'm an avid M1-A shooter, and though I mostly stick to the Portugese .308 NATO stuff, I sometimes buy a few commercial rounds.

Have done quite a bit of informal range testing on commerical primers, and found the "ding" that naturally gets put into primers when they feed is hardly noticeable with Federal (American Eagle) or PMC, but the Winchester .308 puts a significant nick into the primer when it's fed in.   I stopped after buying 40 rounds of Winchester .308