Dear Rflshootr, I have used both HSS and carbide reamers. I prefer my latest reamer which is a 6PPC .268 nk. carbide one. I find that I don't have to run the reamer at 1 zillion RPM to get a good finish in the chamber. The one downside to a carbide reamer is that pesky wire circle clip used to hold the bushing on the reamer. It is very small, hard to get on and off and tends to fly off into the either. Then it becomes very difficult if not impossible to find. The ends of carbide reamers are not threaded for a small bushing retaining screw like HSS but have a small groove on the end which the small wire clip goes onto. If you do decide on carbide get extra wire clips. In the beginning remove and attach the clip in a gallon ziplock bag, cardboard box or some sort of enclosure. Later on when you become proficient with the clip you can try it without the inclosure. Be prepared to lose one or two clips. Additionally carbide reamers are more expensive and more brittle than HSS. If you plan on chambering a lot of barrels carbide would stay sharper for a longer time but HSS steel will chamber a lot of barrels before dulling. Whether to use carbide or HSS I think boils down to personal preference. Which ever choice you make I recommend JGS reamers. I have had my best luck with them. Good luck. ps. I can't help with the diameter of the end of the 22 reamer. Better men then I can help you with that