Overthere, regarding your query about short vs longer range group sizes, probably not.
Groups get larger in subtended angles as range increases. For the most part, that's caused by muzzle velocity spread.
A 50 fps muzzle velocity spread from a .308 Win. at 100 yards causes about 1/10th inch vertical shot stringing, at 200 yards about 1/4th inch and at about 3/4 inch at 300 yards. At 600 yards, it'll be 5 inches and at 1000 yards it'll be over 20 inches. That's a 1/10th MOA spread at 100, 1/4 MOA spread at 300 and a 2 MOA + spread at 1000.
So, through 300 yards, it's pretty close. As range increases, the spread gets bigger.
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Last edited by Bart B.; December 31, 2012 at 10:07 AM.