Has anyone chronographed any 7.62x39 ammo out of a Krebs 103k with the 14.5" barrel and permanently attached comp ? How does it compare ,velocity wise to the standard 16" barrel?

It would have to be slightly lower as there would be less time for the powder to burn.  Its 3:30am. I will look it up when I get home from work.
I wouldn't think you would loose too much velocity though.

Talked to a technician at Sierra bullets today. He said by his calculations the bullet should lose between 50 and 70 fps by cutting the barrel by 2". According to their data in a TC Contender the 7.62x39 only lost 100fps going from a 14" barrel to a 10". I also asked him at what distance a 123 gr projectile starting at 2200 fps would become unstable. By his calculations he said 450 yds seemed reasonable and maybe 500 on a good day. What does all this mean? It means my VEPR is going to Kreb's to get the barrel chopped and a 74 brake permanently attached. Can't wait to get it back !!!