Cocking effort is still quite high. May be because the piston supposedly has no specific seal, it's just a close fitting piece of plastic. That's what the man who assembled these told when we discussed about the possible causes of varying power. So lots of friction between the piston and the cylinder.

Here's the m/72, never seen one alive.





Scanned from
Timo Hyytinen: Arma Fennica Suomalaiset aseet Finnish Firearms, ISBN 951-99681-6-4. Page 266.