Re: Change in poi?
Another set of questions... well okay, I actually have answers, although I am just repeating myself.
The answer is, the shooter is changing his input to the rifle, what JROSE wrote is essentially correct. A rifle doesn't change its point of impact, the shooter effects that...so we consider that a training issue. The original poster, asking the original answer is doing something different to cause the impact shift, especially 2" to 3 inches. It can be taught to remove the zero...
I'm not sure I understand your first line, we don't expect different point of impact shift. For example at 100 yards on the dot targets, anywhere from 1/2" to 1" dots we expect the shooter to hit the target from either side with equal accuracy. In fact we find some people shoot better from the support side, shifts are not expected... hit the 1" dot the same.
The Barricades go from Sitting to Kneeling, to Standing, because of the changes we usually use a 3" Shootin C, but will say, if we just went from sitting to kneeling a 1 to 2 inch dot would be fine, we use the 3" because of the standing and the fact we use 15lbs rifles.
In the kill house, we use a table to shoot off of, a 2" is generally used because of time and the fact we run from the kill house to the bus, to the barricade, to the sewer pipe, to the last barricade... so again a bit more realistic.
Maybe we don't fall into convention expecting things to be how they were once taught. Take the Cold Bore shot, in fact all the books talk about recording your cold bore shot, how your cold bore is always gonna be different because the "gun" heats up and changes its point of impact, well, Leo, bullshit... recent RO training example
Not only was the cold bore shot on a 3/4" Dot, we shoot 2 shots together to show... this was shot with a GAP Sniper's Hide edition rifle #22 by Jim there... tell him he has a cold bore shift. When you do things consistently and correctly these myths of the past seem to disappear. If the idea of a rifle heating up was true, the rounds would "walk" not just to the target but across the target.
Shooter errors should not be accepted but trained to a standard, when you push people in that direction its funny how they step up... you can say, Oh ya, the "rifle" will shift from your bipod to your bag, or you can say, no, do it consistently and it won't and the next thing you know it doesn't.