Sighted in my 7RM in 40 degree temperature and ran the ballistic and the gun shot true to those ballistics (using territed scope). Went out again in subfreezing temps and at 500 yards shot a 4 shot sub MOA group but it was about 7" low. I am using imr4831 which I think is pretty temperature sensitive, but that seems like an extreme change. BTW - bullets and gun were kept in the the bed of truck for a full day in that subzero weather, so they were consistent with outside temps. Any thoughts or explanations? Thanks.