just out of intrest, as the rifle is now liking the 50gr winchester rounds, a factory bullet, what is it shooting the 55 gr like now?? i still think the raw barrel was the cause, and possibly the first type of ammo you used. this is a first class rifle and scope and i would not expect the rifle to have a problem with the 55gr load as most 22.250 ammo here comes in that weight, only the more expensive ammo gives you a choice of bullet weight if you are not into handloading. this rifle should after breaking in the barrel give you moa or under with factory 55gr ammo it is a tikka after all.