alot of new barrels need shooting in when new,my 452 hmr was only doing 1.5" groups at fifty yards,the grouping started to tighten up after 200 shots,22lr is known as a dirty gun ie it shoots better dirty
have you thought about the fireball,less powder less noise less barrel ware for similar performance
linky info
http://www.riflesintheuk.com/cartridges.htm