Rare Hotchkiss Revolving Cannon sells for $92,000 at Rock Island Auction Company auction in Moline, Illinois last December. The gun sold was a naval cannon on carriage mount and included accessories.

An early 7 pounder rifled muzzle loader is for sale at Springfield Arsenal LLC. Ad says in
excellent condition and you can even see it fired on YouTube. And a bargain at $5,500.

pic of mountain gun