I'm posting this in this forum, as it's a recent build and my question is as much about lower parts kit quality as it is the actual failure...

I recently built a nice 16" carbine, using an LMT upper, DPMS lower, and an M&A parts kit.  All parts looked visually fine, and once assembled I put roughtly 450 rounds of 5.56mm through the carbine.

The other day, I hit the range with a new Spikes .22 conversion kit - after a handful of magazines of .22LR, my magazine catch cracked right near the post. A few more presses of the magazine release and it broke clean in half.   One half is still installed in the gun (screwed into the magazine release button), but the other half fell completely out of the rifle.

Is this a common type of failure for this part?  I would assume not, but I'm curious if this is a part that's prone to having a defect in that area (i.e., many fail in a short time like mine did, otherwise they last forever).

Thanks much!

I've also had a broken mag catch (Rock River), but mine came out of the package broken. Given where both yours and mine broke, it had to have been cracked from the riveting at manufaccture..  And no, I've never heard of it being any kind of systematic problem in ARs.

Just two defectively produced mag catches.

I've had it happen with a Stag kit.  Don't think it's all that common, but it does happen occasionally.

Thanks for the replies.  Yet more reason that you really need to wring out these new builds before assuming they're good-to-go after only a couple hundred rounds. :)

I had a bushmaster one break.