I got my M63 a couple years ago. I didn't care for the lock but, have since forgot about it. I wouldn't want the lock on a defensive gun but, on a .22 who cares? It is a quality made firearm.
I never go to the range without it. Minute of Baseball @ 25 yards with bulk ammo.
I got the "M60 Pro" grips on the advice3 of Stainz, they are perfect.