I have an xcompact grip module with the regular compact 3.9 upper on it. So i decided to purchase the xcompact slide, bought a 3.6 subcompact barrel, and a subcompact recoil spring. To my surprise for the life of me i cannot get the new xcompact slide with the new 3.6 barrel and sub recoil assembly to lock to the rear and get assemblied. Any help would be greatly appreciated. Does the xcompact have a different 3.6 barrel or recoil assembly?

From what I've read, the X Compact Barrel is not the same as the standard 3.6" Sub-Compact barrel. The barrel hood is different and that is why you cannot use the standard 3.6" sub-compact barrel will not work on the X-Compact slide.

From my experience with both the Compact(3.9) and the XCompact (3.6) it is the recoil spring! In the XCompact, the recoil spring has two flat sided and two rounded sids where it attaches to the barrel lug. The two flat side must be installed parallel to the slide; the round side, bottom and up. That should make it work.

Yea i read other posts about the recoil spring alignment, i am installing that properly. Ive had this gun for 3 years and disassembled 100 times and the new shorter slide is just not working. About 1/8 inch shy of the slide lock. If the barrel is different that may be the reason. Its crazy because everything else fits fine, its just mating the upper to the lower.