Can't speak for that one in particular, but I have a stock M14A4 rifle, and it's seen about 15 000 rounds so far without any failiure. I love this rifle. In terms of externals, few other stock guns are as durable as CA guns. This goes for pretty much all their guns, including the one you want. I don't think you'll find one model of CA M15 more durable than another.
Apparently, they have crappy hopup rubber and their pistons can fail unexpectedly, but I haven't had any issues with mine to date. That being said, I do have a stiffer spring and a Systema polycarbonate piston, and Systema silent piston & cylinder set sitting here waiting to be installed.
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