I have a p220st internal extractor 2004, and bought the carry model 45 caliber x-change kit. Problems now. The slide won't lock back on last round when firing but works manually. I tried a new slide lever, lever spring, recoil rod and spring, at least 6 different mags. This 220st works flawless with the original stainless slide. I called sig and they sold me a new locking insert #34221660 said it was for carry and compact models, Also that part # is for carbon slide models has 8 dots total, 4 each side . 220st has 5 total dots ONE SIDE. I could have just bought a new carry model for what I put in this kit, hummm. I WAS WANDERING IF ANYONE ELSE HAS USED A CARRY X CHANGE KIT ON A 220 ST? NEED HELP, PLEASE. I would have asked at sig forum but waiting for approval.

You are putting a P220 Carry X-Change kit on a full size P220ST? Are you aware that the overall length of the Carry is .6" shorter than the ST?

Yes, I know it's a shorter slide. But the frames are the same size. Does anyone here have a p220 carry? If so, could you tell me how many dots are on top of the locking insert? I would appreciate the info help.

Haven't heard anything about them not being interchangeable. I am looking for a 220 x-change kit right now, let me know if you want to sell the one you have, or if you would be interested in selling the stainless upper (providing you can get the carry kit to work). Thanks, Chris