I think it depends on your lube. In winter I use Slide-Glide lite - says it's good to 30 degrees. Or you could get some mil spec stuff that is good at lower temps. Temperature will not affect ammunition ignition, but cold, viscous lube will inhibit your firearm from going into battery.
Saw an article about this in American Hand Gunner, have you guys seen this?? http://forum.pafoa.org/pistols-41/123065-ria-22-tcm-have-you-seen.html It comes with the .22 and a 9x19 barrel & spring, the mags handle both the 9mm & .22tcm rounds.
If I remember correctly, the Colt's tube OD is smaller than both mil spec and commercial buffer tubes. I put a VLTOR stock on mine, and used teflon self adhesive tape on the inside of the stock to make it fit the Colt's tube. Good luck with yours, and let us know how it turns out. TM