Originally Posted By: Arizona BushmanA warm barrel will do that.
It takes me a week to zero a hunting rifle, I will bore sight it, then put several rounds on paper and make the adjustments to get it centered @100yds. As it warms up, the groups will get tighter and tighter.
The following day I will fire a single cold bore shot and adjust the scope accordingly.
I will then continue the process of once a day cold bore shots until it hits dead center every day of the week right out of the bag........call me anal, but shot groups don't impress me much, dead coyotes on a cold morning do.
IIRC, that's very similar to the way Carlos Hathcock sighted in his sniper rifles.
The COLD BORE shot is the most important to me. But, nice tight groups are lots of fun too.