Powder type, speed of burning and energy produced per grain weight also has a direct effect on recoil. Bullet wieght is not the only aspect of recoil energy.
; Felt recoil is another thing entirely. Stock fit, shape and weight also effects felt recoil.
; Ever shoot a 5-1/2 pound, 3" 20 bore Semi Auto - Franchie, I think it was. I had one that kicked more with it's 1-1/4 ounce loads than my 8-1/2 pound 12 bore Browning over/under with 3" factory 1-7/8oz loads. Stock fit and weight made the difference.
; Fired in the same gun, bullet weight makes the difference, even though the powder charge is usually less with heavier bullets. This, of course, depends on the case shape and capacity. The smaller cases might use a higher grain weight of slower powder with a heavier bullets. It all depends on powders used, but the heavier bullet will be found to kick more.