Bought a real whitworth from a fellow cgner in 458 win mag, and man oh man group. Rival my sako 22/250...Now what I'm starting to notice is that its a tad less able to group...I made the mistake of not firing all the 50 brass the same times each with the same load each,etc,etc. So now I'm noticing slight recoil diffs,slight primer seating pressure diffs. The average # of loads is 5 near max. Some pieces 4 some six...Even though none of the brass are showing major probs,could these very slight diffs. be causing slight chamber pressure variations,thusly grouping probs..My opinion is that it would. My buddies opinion is that as long as a straight wall case will hold a primer the grouping shouldnt change...Any thoughts???