reb87 is correct, I believe. Recently a Hopkins & Allen 44-shot that was restored was on GB. It went for over $600. I am relatively sure that was not quite equal to what was invested in the gun.

These turn of the century single shots were a very popular gun. Harrington and Richardson had to enlarge their factory 3 times in a 5 year period to meet demand for their single shot guns.

Yours looks to be in relatively good shape.

Pete