hi guys, just wanted to share a little info, most of you probably already know this, but the M model mags will fit the S model guns. the only difference is the bottom piece. you can actually cut about 1/2" off of the M piece and notch the sides to make it look like the S piece. the mags end up looking identical. so far, i've put 200 rounds through my modified M mag, and have had no mis-feeds or any problems at all. also, the High-Cap M mags have the same bottom as the S mags. I was able to purchase M model mags from http://www.cdnnsports.com for $9.95 each, where I was unable to find a good deal on S model mags. Most people are trying to get between $25-$35 for a used mag and around $40 to $50 for a new. If you are worried about the mags having a problem, I would say maybe only use them for target shooting, but, like I said, i've had 20 full mags through my modified and haven't had a problem yet.