I shoot a M41 and it is pretty finicky. (Most .22 brands will have issues in it, except for Eley, Federal Target, and CCI Green Tag.)
The most inexpensive stuff that I have found that it shoots, (that I shoot almost exclusively because of $$), is Dick's Sporting Goods blue box Federal Target. ($16/brick of 500). I have had one fail to eject, only.
Two out of the last three matches in Bullseye I scored in the low 870's/900.
Pistol is tested, they say, in CCI Green Tag; but, on sand bags at 25yds, I can't tell the difference. (I can't shoot off sandbags well enough to tell, tho'). It is way more expensive at $7/100, so I don't bother.
cavman