I was wondering if anyone has any insight into this. According to a test done at the Aberdeen Proving Grounds, a bullets spin decay rate is approximately 2% per 100 yds. Bullets shed velocity at a much greater rate than spin. I understand that a bullet may only make 1-2 revolutions while passing through an animal, but what effect is there on the terminal performance. Using a 1:10 twist barrel of .308 for each. If we plug some basic rough numbers into a comparison we find a 300 WM shooting a 200 gr bullet at 2900 fps mv spins at approx. 208,800 rpm, 2500 fps @300 yds turning 194,000 rpm, and 2200 fps @ 500 yds turning 185,800 rpm. A 308 Winchester would have the same mv as the 300 WM @300 yds but would be spinning 180,000 rpm (7% slower for same velocity), and would have the same velocity at 200 yds as the 300 WM at 500 yds but turning 172,800 rpm vs the 300 WM at 185,800 rpm (again, about 7% slower). All this to ask, with this roughly 7% difference in rotational velocity, would a bullet perform significantly different out of a 308 than a 300 WM at an equal velocity but different rpm? In other words, would a bullet fired from a 308 Winchester have the same terminal performance at 200 yds as a 300 WM at 500 yds (same velocity)?