What gun is this

[Nuts]

One of the guys at work just picked this up for $10 at a garage sale. He couldn't figure out make. Came with bullets which he said are large. I didn't see it yet. Any idea

 

[Ben Lamb]

Looks like potentially a Snider-Enfield rifle? British (and a ton of other nations/colonies) military from around 1866-1880 when it was replaced with the Martini. Should be chambered in 577 Snider