I think it is a decent, although worn finish and the strawing has simply faded to natural loss - bore pictures escape me when I try to take them, so no luck there
I would say I would be trying to sell it at a table for $750-$850 - depending on the magazine, perhaps a bit more. No offense, I call these a starter collectable.
My two cents
Remington 51 - depends on condition - lower quality the less value - mid-range is around $450-$500 (+ or - on condition)
Schmidt 1882 Ordnance - no idea, sorry
Enfield NO. 2 MK - not sure which variation - much depends on variation, (this is the rifle?)

I was going to say caliber, but I assume that it has a date and such on it?
Ed