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I'm stumped by the lack of change in the zero as the windage on the mount changes. With any rest, forend in the front bag, moving the windage a few inches moves the zero or POI relative to the aiming point a bit-enough to be a bother. This effect has been common with my guns for many years, is frequently mentioned by other shooters, and is easily reproducible. The only methods I've found to make this go away is to have the front rest top easily rotate, or use a muzzle clamp. Some time ago I wrote the following, from UPDATES in the book. 7.3 THE WANDERING ZERO PROBLEM When shooting from the bench, the group center moves relative to the aiming point as I go from dot to dot. The targets I'm talking about are 24" X 24" pieces of paper with sets of dots spaced ~ 4" apart, so a set might be, from the left edge of the paper, at 4", 8", 12" 16" and 20". Sets might be spaced 4" apart in eight. My impression is that generally the group center moves in the direction the gun is moved. If the rifle is moved left to shoot at a dot to the left of the last one, the group center will move to the left. This is merely an impression, not any kind of rule. Sometimes the group center moves up or down when the gun is aimed at another target. I'd like to know why this happens, and how to cure it. I have no guns with "bench rest" 3" wide forends. I use a Hoppes front rest with a Stoney Point Universal Front Bag, (4.75" L X 2.5" H X 2" W), and a Protektor rear bag. The front bag is attached to the Hoppes rest with double-sided tape and the Velcro holder things. The front rest is free to turn left and right, the top piece is free to rotate on the shaft. Everything else is locked down. Coarse elevation adjustments are made on the Hoppes front rest; fine elevation adjustments are made by sliding the gun forward and backward. Clearly, windage adjustments are made by moving the rear bag left and right. I put baby powder on both front and rear rests frequently, to eliminate friction
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