Semi custom M70 fwt 280 em. when zeroed it shot a 5 shot group that was sub half MOA. took it home and cleaned it thoroughly. took it back to the range today and the first shot was 6 inches low and 3 inches left. next two shots were and 2 inches left of center and dead center vertically. next shot was an inch further right adn an inche higher. the next several shots were dead center adn 2 inches high. Right where the original zero was. all I can think of is that the rifle likes to be dirty
Ive got one like that John. Mine takes about 3-4 rounds from a clean barrel to come in to where it belongs. Odd part is when you switch loads, it takes a couple round to refill it with whatever is different before it starts grouping again.
