This unusual pistol is a Colt 1851 Navy Revolver. That model was made in massive quantities for two decades and used long afterward. What makes this particular variant unusual is that it comes with a detachable hollow pewter buttstock. There's a plug on the top that you can open to fill it with water.
NEATOSHOP SUMMER SALE: SAVE UP TO 20% OFF ALL T-SHIRTS
Save big on Funny T-shirts, Science T-shirts, Sci-fi T-shirts & more! Ends 7/12/15