I built two guns on Caspian high cap frames. One in 40 and the other in 9mm. I had a terrible time getting the new Caspian mags to run. After speaking with Jim via PM I did as he suggested and squeezed the mags a little. That helped, but I was still getting lots of nosedives. Using both stock springs and followers as well as Grams stuff for the Tanfoglio mags. I finally solved the problem with the simplest solution. Pure silicone spray. Take your mags apart and clean them real well. Then spray the inside of the tube, spring and follower with Pure Silicone Spray. Viola, not one more nosedive for me in the last two months (~2500 rounds). I couldn't believe that this solved my problem, but it did. The mag issue was driving me nuts and I was going to send them off to Jim to get them running, but I found the silicone spray first. I use the stuff from Ace Hardware for about $3 a can. Hope this helps.