.......unsupported chamber...??
Glad your alright though - i had the same thing happen to me once with a Action Arms Galil ARM
in 5,56mm. The gas produced by the powder (+50,000 PSI) usually follows the path of least resistance - looks
like alot of it went into the mag and blew out the side - in my situation it blew the bottom of the steel 35 rd IMI mag
off and cracked the receiver - very scary indeed !!
With the 106 series - the early production rifles had issues with the feed ramps and jamming,,Arsenal corrected it after while
on production guns but a few people took to the ramp with a dremel in a sort of home fix...there was even a sort of "how too"
topic listed in the Ak section here...
Not saying this is what happened in this case but ya never know, Anything mechanical can does fail.
Is the barrel clear -? Sometimes an "Underloaded" round can also cause the same issue...
Have the rifle taken to a gunsmith and examined. Contact Arsenal and ammo manufacturer..
In my case Action Arms and Norinco (shows you how long ago that was) split the cost on a new Galil for me.
My incident was on video tape and both companies got copies via certified mail. (Both blamed each other) I am
not a sue happy person and just asked them both to "fix" the situation... the rifle that KB'd was fubared since the milled receiver
"cracked" and did not "flex"
Here is a kind of "how to" pic of what someone did to increase reliability of their early production106. If not done correctly could/would make the
chamber unsupported and only a matter of time before a KB...Drop a round into the chamber and see how much brass is exposed on the bottom..a little is fine - but not too much. A Dremel Tool can be a dangerous device. .