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.