It should be safe with any .22LR loading on the market. You'll have to experiment to find out what is most accurate in it.What about grains...what would be to much for the Ruger MK lll?
Yep. I just went through a lot of different brands and power levels of .22LR (even one box of .22 Shorts) ammo. Shorts shot way low and didn't group well BTW... Found the Federal match grouped the best, and Federal Bulk was next in MY Colt Scout SA. Each gun is going to be different ... so you need to experiment.You'll have to experiment to find out what is most accurate in it.