Well now, being picky is condition we are all cursed with. But you have a mighty fine shooting rifle there and I intend to show youhow I come to that conclusion.

Wind is contributing to the horizontal spreading, that is evident, but lets first look at the vertical spreading. There are three major factors affecting the spreading, firstsighting uncertainty, second bullet instability, and third, variations in muzzle velocity. Using the lead sled, from the way you describe the sights upon discharge, lets say you have eliminated sighting uncertainty. So the effects are bulletinstabilityand velocity variations contributing to the vertical spreading.

The muzzle velocity of your load is in the neighborhood of 1990 fps. If you aren't weighing the charges, then I think its reasonable to say that your velocity spread is at least 20 fps if that tight, which correlates at 150 yards to be a .26 in difference in drop. Lets subract that from your vertical spread to get 1.4 in. Well, that is sub MOA and your bullet must, at the very most, add .93 MOA to your groupings at 150 yards. If your muzzle velocities ranged more than 20 fps, then the bullet instability MOA is better than .93 MOA, for example, if its 50 fps, then bullet instablity MOA is better than .5 MOA at 150 yards.

Now lets look at the horizonatal spreading. Assuming bullet instability MOA of .93 MOA,lets determine the minimum wind speed fluctuation required to cause the horizontal spreading. Lets subract bullet instabilityspread from the horizontal spread. We get 3.38 - 1.41 = 1.97 inches. We just need to punch some numbers into a ballistics calculator to find what wind speed is require to deflect 1.97 at 150 yards. The answer, 2.7 mph. Not alot wind actually.

Hey, I really think you have a great shooting load and rifle there. I've been conservative in calculating bullet instablity from the vertical spread so I really do think the bullet instability is better (smaller) than .93 MOA at 150 yards. Its a shooter!