How much vertical stringing did you have? If there was much...say an inch or perhaps more, it could be a sign of poor ignition, but, from your description of the groups I don't believe that's the problem at all. 57 grs. of 4064 should pretty well fill the Whelen case and prevent any ignition problems. I agree with Michael on consistent placement of the forestock and the heat. Michaels advice is good, cold, fouled barrel...and that could be beat to pieces with varying opinions but I'm not opening that can of worms. Good shootin' by the way!
Vic
