My first limited racegun was a Para built by Gary Kimball here in the Springs. I had three Para mags and all the others were STI. They hold two less rounds, but are more tapered than the Para mags and seem to reload faster and easier. For me anyway. Ther are 140mm long, not flush fitting like the Para mags. Brownells has them for cheap. If you need some, look me up. I am in the area, for now.