Leo is right as usual on this subject. I know of a little double rifle that started life as something in 8mm which was relined to 25-35. Couldn't hit the broad side of a barn after the reline. It had to be sent to K. Kercher in Bend to have a new regulating wedge built and installed AND then the rifle barrels regulated. it ended up shooting quite well with star shaped composite groups of 1.5 inches at 50 yards. Really good performance.... considering. Jeff