Those Russian Bayonets can be a pain of they get stuck on.. HAve you tried placing a brass rod on the base of the bayonet and do some hits with a hammer...??? That has worked for me.. and the brass will not mar things. I have seen people heat up the bayonet with a hair dryer before doing the hammer beating.

Supposedly in the war those Rooskies keep their bayonets on 24/7 because the barrel harmonics was different when you take the bayonet of.