Mike,I get 5.53-5.54 mm head size and 23 gr weight on the ones you sent me
I never have checked the Kozak for choke, I just ASSUMED it had some choke. next time I have the barrel off, I can push a pellet through. If I remember toDid you ever get your FX chrono and do a shot count on your 177 Kozak since your hammer spring change