Recoil is quite severe, even with the built in mercury device. Frankly, the gun just isn't heavy enough, IMO. It should be 1.5-2 pounds heavier. I also use the .416 Rigby and find that the .505 recoil is significantly worse than the Rigby. I may someday add some additional mercury reducers.
I have taken to downloading the cartridge slightly, from the factory 2300 FPS (Kynoch never apparently achieved that velocity anyway) to the more typical Nitro Express velocity of 2150. This does help, but I still don't fire more than a magazine full at a time. For extended practice, I use a case full of Trail Boss over either a soft point or a lead bullet (from a custom mold). This gives in the neighborhood of 1200 FPS with very light recoil. The reduced load is the only even reasonably "versatile" thing about the gun, as they can be used for any North American non-dangerous game. With the looping trajectory, of course, you have to get close though!
Reloading is a snap compared to the Rigby. I have never run into any of the shoulder difficulties that I have with the Rigby. I have generally had best results with Reloder 22 and Woodleigh bullets. Federal 215s, naturally.
Overall, I'm happy with the gun, but I spend a lot more time admiring it than shooting it!
