The SIG 522 might be nice but it's not a "M16/AR15" system. For plinking a Ruger 10-22 is still the best available today. But if you're looking for more "M16/AR15" trigger time you need a clone of one.

I've seen out of battery firing on many .22LR self loaders. The firing pin might strike the rim or the rim gets crushed during incomplete or partial loading. If we can determine what's happening we can help S&W device a redesign or fix.

I'm pretty sure this is what happened when my extractor went missing, but didn't notice the case. Nor did I have to pry a blown case out of the receiver.

-- Chuck