2550 fps 500 Gn WhbY 10lb gun 108.27flbs @ 26.41 fps

2100 fps 750 Gn .577 NE 12 lb gun 140.12 @ 27.42 fps

2100 fps 750 Gn .577 NE 11 158.86 @ 29.92 fps

To duplicate the recoil of the .577 in an 11 lb gun you would have to fire the .460 WbY in a gun weighing only 7 lbs

Or to duplicar the recoil of a 12 lb .577 you need to use a 7Lb 10 oz .460 WbY

Enjoy

Regards