Can you explain positive compensation to me? I'm trying to understand what you are describing.
Google will provide better than I can type. But here’s the cliff notes:
You are tuning to your barrel “harmonics” (harmonics probably isn’t the absolute perfect word, but that’s what most people understand) for a given distance.
You are tuning so that slower rounds exit the barrel at a time when during the barrel “whip” the muzzle is pointed higher. This in turn makes up for the velocity difference. It’s basically only good for the range in which you adjust/tune for with seating depth and/or a tuner.
For example:
You have a rifle tuned at 1k yds. You fire 5 shots with a labradar showing all the velocities. They are:
2950
2960
2955
2970
2940
Your low is 2940 and high is 2970. @1k that’s a .1 or so difference. That’s 3.6”. But you’re still able to hit X’s (just using F class as an example for the target size) which is 5”. Well, if you have 3.6” of vertical just in the MV variance, what’s happening here?
You have the rifle tuned where the faster rounds are exiting the barrel on when it’s “pointed down” and the slower exiting when it’s “pointed up” during the barrel whip, so they are grouping better than the math says they should be able to do.
This is why you’ll see a lot of “people put too much effort into ES. I’ve had ammo with a wide spread in velocity still shoot a small group at X yds.” And when you see their MV variation, the math says it’s impossible to shoot a group that size.
That’s the theory anyway. And anytime someone says they don’t believe it (I’m completely open to it not being real), I always ask “well, what is the explanation when someone consistently shoots groups that should be mathematically impossible based on the MV variation, and they are a skilled enough shooter it’s not just luck?”
So far, no one has been able to provide an explanation as to how it happens when the math says it shouldn’t.......without positive compensation being the answer.