the improper design of the magazine follower allows the bolt to "slam" into it when teh magazine is emptied instead of properly activating the LRHO. the resultant whack agaisnt the frame will break it in short order.
would explain how the original frame on my 995 (the one I just upgraded to the TS stock) was broken (when I bought it used unbeknown to me). It had one of them pro mags.
wow. I need to get a factory mag for it before I shoot it again.