My friend ownes Hinson's rifle. I have handled it many times. I pulled measurements off it so that a replica could be made. Target shooting was a very big deal during the 1850's. Hinson's rifle (according to knowledgeable gunsmiths) is typical of the target rifles of the era. The barrel is very heavy, also typical.
The most surprising feature is the pistol hammer & lock. The physics of the hammer are such that it could spoil the aim when put into motion. The common solution was to use lightweight pistol locks. The first time I saw it, frankly, I thought it looked kinda goofy. I can't, off the top of my head remember the caliber, but it isn't .50. Target rifles were pea shooters.
There are notches marked into the barrel. Near the muzzle are the ones that marked the Confederates he shot. All of that is, of course, purest fantasy. For good reason, Hinson never said a word about his wartime exploits.
Please don't get your dander up, but the book everyone is familiar with is a work of fantasy. Very little that is in that book holds up to the light of day. So, before you send outraged emails, go to the Soldiers & Sailors website. The Iowa regiment that Hinson was supposed to have plinked with impunity, did not suffer any losses while stationed in Hinson's neighborhood. The rest of the book is equally fanciful.
Exactly what Hinson was up to, he took the story to the grave. As was the custom, Hinson's rifle was intended to be fired from a rest. I am a big man, but would not be able to hold the terribly front heavy rifle & shoot with any accuracy.
My go to friend for all things historic historic weapons went to Hinson's cave.He tells me that, with a lot of practice, a marksman could have sniped at passing river traffic. Firing down hill is very difficult. Hinson had plenty of time to get the hang of it. I accept his expert analysis. He did say that the claim that Hinson caused a gunboat to surrender by plinking at it from his high perch is laughable.
Hinson's rifle is no different from other target rifles of the period I have held. However, not a one of them had the kind of notoriety that has. Nor has any of them been associated with such an often fanciful violent history.