Interesting test by Potterfield regards “drop” on a shotgun. Can one change the drop by changing the heel (shims) or must it be done at the receiver? Not sure my gun would accommodate shims at the receiver.
How high a gun shoots is a function of the eye’s relation to the rib. The higher the eye is in relation to the rib, the higher the gun will shoot- if all else is equal.
The eye can be raised or lowered in two ways.
1) If the head angle is kept constant, then the height of the comb determines the height of the eye vis a vis the rib. A higher comb will raise the eye and allow the shooter to see more rib and the gun to shoot higher.
2) If the head angle is changed so that it is more erect or sloped further forward, that will also change the eye’s relation to the rib and make the gun shoot higher or lower. Changing the head angle can be done by using an adjustable butt plate. Lowering the butt plate will raise the entire stock and force a more upright head, thus showing the shooter more rib and making the gun shoot higher.
Note that changing the angle of the head changes the entire shooting style of the shooter. It’s a big change and not one to be taken lightly.
Most modern gas autos now come with shim adjustable stocks where a shim is placed between the rear of the receiver and the head of the stock. You can adjust for height and cast quite easily. O/Us don’t lend themselves to shim adjustment in the same way and generally have to have their stocks cut down or bent up to alter head height if head angle is to remain consistent.
Shotgun Report’s Technoid