I have the SF Pro, can't use the mag well for USPSA carry optics, but it does come with three 17 round magazines. I had magazines for my polymer Q5 with + 5 TTI magazine extensions that gave me 20 rounds each mag and they work in the SF with the mag well. With my Polymer Q5 I could Barney up (one in the pipe and 20 in the mag) with no problem. With the TTI I couldn't Barney up as there was to much pressure on the slide and caused the first round fired/cycle to malfunction. Also, I discovered my reloads that what worked well with the polymer Q5 were to short (col) for the SF Q5 as I had multiple malfunctions and a few failure to lock back on last round fired. I increased the COL and made the rounds hotter and my first competition I had Zero malfunctions. I did notice some magazine side to side free play, but nothing like the video I had seen posted.
