Depends on which model and condition, condition, and condition....
In order to determine the exact value of a Remington Rolling Block rifle, a few different factors would need to be taken into consideration. Some of these things would be the age and condition of the rifle.
Civil War was 1861-65; obviously, the Remington rolling block came out later. Is it a military rifle? What caliber? What condition? All these things affect value. Ranges of rolling blocks are from $550-$4000.
Not enough information to even hazard a guess.
About $500 and up.
Which model?
Hexagon barrel what? Model? pump, rolling block, ?? Condition?
My research indicates about $300.00 in good condition, and that is for a model 4 in .32 long caliber.
The 20 ga shotgun was created by reaming-out the 50 cal. militery musket. I have only seen one.
Remington didn't make a Model 1 shotgun, if it's a #1 Rolling block it could be shot out but it's no a shotgun. I doubt however you could have identified a Model 1 Rolling Block vs all the models but not know it's not a rifle. Best determine what you have and need a VERY good description (for identification) and value.
nation Remington rifle pat may 5 1864 ilion ny. usa marked nov12,june11,may3,dec31 sept 1872 312872stpta
That's a rolling block pistol, from $1 to much more, depends on condition.