Having had good luck with Elite Tactical Systems (ETS) magazines made for Glocks, I was anxious to try the ones recently introduced for the Sig P320 and in my case compact model. I was interested in using the magazines solely for range purposes and not for personal defense. The price point is very attractive, as is their lifetime warranty. My initial range session with the 15 round magazines had some bumps in the road. I bought 3 magazines. On the plus side is that the magazines work in all Sig P320 Compacts, even the X model. The first range session was very disappointing. The magazines tended to bulge with loaded to full capacity. The slide couldn't be released using the "sling shot" method, but they all worked well when the first rounds were loaded by pressing the slide releases on the pistols. I had several problems with the slide locking back while rounds remained in the magazine. I contacted ETS and they advised to keep the magazines fully loaded between range sessions. After a week of keeping the magazines fully loaded the problems diminished, nearly entirely. At today's range session, one magazine was still bulged enough to make inserting the fully loaded magazine requiring a little extra effort. All the magazines worked when the first round was stripped into the chamber using the sling shot method. One magazine will lock the slide back while there is one live round left in the magazine. My conclusion is that after the "break-in" period, two of the magazines will function plenty good enough for range work and, I'll probably return the one magazine that makes the slide lock open with one live round remaining in the magazine. For $15.29 ea., I still think overall, they'll end up being fine for my purposes.