If you hold the rifle the same, and only use the bench or bags to support your hand or elbow as you sight,(holding the rifle the same) there will be no differance in your sight window.period. I cain't tell ya how many times I have seen folks put the gun on the bags,then hold the gun in there hands and gripe/(confused) because the shooting is different.
HOLD THE GUN THE SAME. Use the bench or bags to steady only! Hold the gun the same every time! Don't put the barrel on the bags! Don't put the stock on the bags!Put yer gun in your hands like always and put yer hand on the bag!
simple physics. Newtons third law. For every action there is an equal and opposite re-action..if you change the physics of the re-action the point of impact will change. The gun is doing the same thing,,(mechanics)(easy,powder,patch,ball)yet buy changing hold you have changed the physics of the re-action. simple,,I can "bench" my hand on my knee,or x sticks,or a log, or a tree,,,if I "bench" the stock or barrel that's different.
sorry but that's it,when ya learn that much then comes the off-hand tactics,,breathing, stance, muscle fatigue, vision and light, diet and excercise. If there's a 3" differance tween bench and off hand at 25 then we need to get back to basics. Sorry if you think me rude,, but we need too learn to hold the gun the same all the time first
BTW spot, welcome back,,did ya ever find any vous' near ya? A local rendezvous is a good place to learn off hand shooting skills.