Nothing as far as I know, some of these were lend lease to the British military shortly after WWII and were supposed to mimic shooting the enfields. I believe the 42M and 42M A primarily filled this roll.
I really wanted a bolt action 42M for mouning a YHM mite suppressor on, Buuuut I Just spotted a 151M C for a good price (comparatively) GORGES walnut on this one. Trying to get it