I shoot a 30 grain load of 3F in my 36 caliber rifle with PRB. And that is not a stout load by any means. But my rifle shoots 30 grains very well. I have shot up to 50 grains of powder in the rifle. But my rifle shot a pattern at 50 yards-not a group. My rifle will consistently hit a 2-1/2" gong every shot with a 30 grain load. I have yet to shoot a squirrel with the rifle. And I will probably be selling it since I ordered a new rifle. But 30 grains should work well for you.

Also you got a good deal on that rifle. I have seen them(in top condition) sell for $250 to even $300. So you did well!! Tom.