As I recently mentioned in another thread, I picked up a preban M17s yesterday. Just to have something a bit different, yet still be able to legally have the flash hider installed. I decided to shoot a 30 round mag through it this afternoon just to see if it would run. Bad idea.
I turned on the red dot that came with the rifle, shouldered it, and slowly fired off 10 rounds. The noxious gases from the chamber were bad. I looked the rifle over as I got a lung full of fresh air. I reshouldered the rifle and commenced to fire 10 more rounds. Once again, the gases coming from this thing were horrific. Nothing visible, just chokingly strong. I decided to finish off the final 10 rounds with the butt of the bullpup tucked up under my shoulder so I wouldn't have to endure the fumes. I swear it was that bad. That God I didn't have it shouldered when this happened.
On the 22nd overall round, the pup made a very unusual "sproing" noise. Along with the noise, I felt my ribcage area burning like fire. It took me a few seconds to realize what had just happened. It had blown the floorplate off the OKay USGI mag, the upper was separated from the lower, and a wadded up case was stuck in the upper receiver. Not in the chamber. The barrel was clear. Upon further review, a large hunk of metal from the inside of the upper receiver was peeled back along one of the internal rails that the bolt carrier slides in. The bolt/carrier was not damaged.
The only thing I can think of is that the push pins had walked out. Still though, the bolt carrier slides entirely within the upper. Just because the hammer and mag (within the lower receiver) had dropped away, you wouldn't think it would cause this much turmoil in the chamber area.
Any thoughts on another cause of this malfunction?
This what the rifle looked like after the malfunction.
The wadded up round of South African.
The inside of the reciever.
Sorry about the poor quality pics. Maybe you can get the idea. Who should I contact at BM to get this taken care of?