5.56 BCG from IMI, I think. It has roughly 500 rounds on it, likely less.

The first problem with it was that the cotter pin that retains the firing pin would be bent every time I cleaned it. I never figured that out, but decided I didn't care.

Today, one of the screws holding the gas key sheared off under the head. The key is still tight, and there is no sign of the gas tube taking a beating. The head bounced around in the trigger area causing a few problems but no damage.

Do those two events seem related to anyone (aside from being a sign to not buy IMI BCG's any more)?

I think I'll spring for a better BCG and put this one in the box as a spare after fixing it. What should I buy?