I'm going to have build two Krinks off kits from KVAR.  I'm looking at all three calibers and it looks like from the kits that both of the 7.62 kits don't come with trunnion blocks (an extra $60) but the 223 and the 5.45 kits do come with trunnions for the same price.  My plan is to use one of my extra 9mm Coastal cans as the extension to get up to 16"+.  I'll have the can re-built and permanently attatched.  Obviously the form 4 is approved on the can long ago.  Not too worried about major sound suppression but I'm kinda leaning towards 7.62x39 just for cheap ammo, however .223 would be great as I'd have ammo compatibility with my RR M16.  I know there can be problems with 223 mags, however.  The 5.45 is a nice option for cheap ammo also but it's kinda hard to get around here.  The second Krink will most likely be a 16" 5.45x39 using the KVAR kit so that one is pretty much set.  Anyway, opinions are welcome.  Thanks!

Guess I should add that it's kinda being decided for me.  My builder just ordered a 5.45 and a 7.62 reciever so I guess that's the way I'm going.  16" barrel with fake can over it for the 5.45 and my real can perm attatched for the 7.62.  Should be cool!

Good luck on your new build. You should end up with one sweet gun. If I were keeping it historically accurate, I would lean all the way to 5.45x39. Awesome round with less recoil then the 7.62x39 Krink. Been unable to simply walk into your average gun store and find the ammo can suck for most shooters. 7.62x39 is a good choice and so easy to get but i personally would skip it on a krink . 223, while not a russian round, would still be a good alternative. Small rounds wailing away out of these small guns is my choice. 7.62x39 would be my 3rd choice, IMO.

I was in the same situation. I had one of each caliber built in the period of a year!