Loss in Terminal Perfomance due to Krink barrel length?
According to what I have read 7.62X39 with most bullet construction is pretty similar to 9mm in terminal ballistics unless you are shooting the Yugo round.
How much does the reduced barrel length affect velocity and terminal ballistics?
negligible from everything I have read.
Regarding muzzle velocity I've chrono 300 to 400 fps difference (avg 360)
between a 16" and a krinkov.
With the loss in performance would a 5.45 or a 7.62 have better terminal performance? The comparison is between 7N6 5.45 and Yugo M67 7.62X39.
the AK in either the AKSU, or 104/105 configuration does not seem to suffer by enough to be a deterrence in either caliber. They do not have the same issues that 223/556 does is what I'm trying to say.
if you're shooting with optics on a bolt gun in these calibers then the difference may be something you would want to know, but for an AK, it's not going to matter IMO