The weight difference depends on which .45 revolver you are using. A quick check of an old book, tells me that an N frame S&W (6") can be 4-5 ounces heavier than a standard Colt Govt Model (1911A1).
A 4" med frame gun (S&W M19) is about 5 ounces lighter. A Ruger Blackhawk (7.5" barrel) weighs the same as a 1911, although the balance is much different.
The size, and shape of the grip make a big difference in how one "feels" the recoil. Also, the "spread out" nature of the auto pistol recoil makes a big difference, too. In an auto pistol, the moving mass of the slide changes the feel a lot, compared to a revolver.
Also, the height of the bore axis over the grip makes a big difference, too. Revolvers place the hand further below the bore than autos, and while the recoil energy of the round may be identical, the effect on the gun (muzzle flip) is significantly different, even when all other factors are the same.
Shooting .45ACP from a 1911 and from a 7.5" Ruger Blackhawk is an interesting comparison. Both guns are about the same weight. Both fire the same ammo. But the Blackhawk, to me, recoils less. Your experience might be just the opposite.
My opinion might be colored by the fact that I rarely shoot .45ACP from my Ruger, its diet consists almost exclusively of .45 Colt, a 250gr SWC at 1100fps (handload). SO, by comparison, .45ACP in the same gun has a lot less felt recoil. Not quite bunny phart loads, but it feels like there isn't much there, compared to what I am used to, in that gun.