The .577 Snider was, for sporting purposes, a short range cartridge. The 1960’s Kynoch catalogue showed a drop of 13” at 100 yards and 57 inches at 200 yards for a 480 grain bullet at 1,250 fps muzzle velocity.
For military purposes with ladder sights it could be effective at much longer ranges, but when I had a 3-band Snider rifle it became clear from shooting at paper targets that the steep rise and fall of the bullet, even at moderate ranges below 200 yards meant that it would be very easy to shoot over or under the vital area of a deer.
The fact this rifle has a single leaf (for 100 yards ?) indicates to me that it was probably built for the Snider cartridge.
If it was rechambered for an express round early in its life that might explain the apparent double set of proof marks.
