I purchased some aammo for my 1911 45. I bought 240 gr and 185 gr thing the lighter would kick less. I loaded one 240 gr then a 185 gr alternating until the magazine was full. I shot one and then the other until all 7 were shot and I noticed no difference in the kick of the pistol. My question is ....Why.
Don't waste forty years making the same mistakes I did WHEN all you have to do is ask! Just an old man who cares.
The total weight of the powder and bullet and their velocity. So a lightweight bullet moving much faster than a heavy bullet can easily have more recoil. Also the recoil is subjective unless you actually measured it. The lighter bullet may use more powder, and or may just have more velocity.
I agree with Edge. I shoot 147gn bullets over 115gn because of velocity. As far as energy goes (recoil or impact) velocity counts for more than mass. The right powder with a heavy can give smoother and softer recoil.