Normal formula for estimating recoil velocity, from which is then derived recoil energy, adds total total wt of ejecta plus 1½(?) times the powder charge times muzzle velocity. The 1½ may be arbitrarily modified according to muzzle pressure. A .30 cal magnum rifle for instance firing a 150gr bullet ahead of 75gr powder, obviously has a charge wt ratio .5 (powder to bullet). A 12ga shotgun with 1 1/8oz shot, 35grs of wads, ahead of a 26gr powder charge has a CWR of .05, notice this is a factor of only 1/10 (.1) that of the mag rifle. It should be quite obvious a muzzle brake is not going to have the effect on the shotgun it does on the magnum rifle. In fact the benefit reaped will be small indeed, but it is real & "Measurable". Extremely funny noone seems able to feel it, but so many can feel a forcing cone, which has no measurable effect. In both cases assuming actual velocity unchanged. Shoes I guess what a good "Promo" salesman can accomplish.
