The competitors in British Commonwealth Fullbore matches were probably the first to figure it out. Their SMLE 303 rifles shot smaller MOA groups vertically at 500 and 600 yards than at 1000. The only way that can happen is if bullets left the barrel on the muzzle axis upswing.Makes one wonder how anybody ever shot accurately before knowing this.
Same ammo in Mauser 98 actions shot smaller MOA groups at 500 and 600 yards than 1000. Its same profile barrel whipped different in such a way to reverse the SMLE reason. The 98 action and stock whipped its barrel different than that of the SMLE.
303 ammo had a big spread in muzzle velocities. When 7.62 NATO ball ammo was used, its smaller ES mitigated much of the problem.
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