Remington Rolling Block
 

There have been many folks to "Sporterize" Rolling Block actions. The action is very strong, built originally to take a .50/70 cartrige.
Most of the conversions I've seen were made from the .43 cal Spanish Contract Rolling Blocks as they do not have the collectors value of a US Martial Rolling Block. The action can be used to build just about any caliber of rifle.

What ever you do, DON'T sporterize a U.S. Marked Rolling Block.
In good condition they are worth close to $2,000.

Remington made many sporting rifles based on the #1 action (Military Musket/Rifle Action) They were made in rimfire in .22, .32, .44 and .46 cal. and in centerfire 40-50, 40-70, 44-77, 45-70, 50-45, 50-70 and other center fire calibers. Some were even barreled as shotguns.

Col:
BTW the 1816/36/62 is a smoothbore.
Pulled out the rolling block. 33 3/4" barrel. Three bands. #10539 stamped on trigger assembly and breech tang. "F Remington stamped along with pat through March 18th 1874. "U" stamped on the bands. Cleaning rod has a slot in the end for a rag. "J" is stamped in the top of the stock right next to the breech tang. No idea of the caliber.
I know these were made, or used, all over the place. Any ideas on this one.
Again, thanks for your help on the Harpers Ferry.

The last US Military Rolling Block
 

Was the Army Mid. 1872 made by Springfield so I'm guessing that yours is Swedish or Spanish. If Spanish contract it's .43 cal. The ammo is available from specialty shops. I'll try to find you some contacts. Does yours automatically go to safety (half cock) when you close the breech when the hammer is on full cock?

Remington Rolling Block #1 Military
 

eds...did a little research last night. Remington produced over a million of these between 1867 and 1888. In some cases Remington only supplied the actions for foreign contracts with the guns themselves being assembled overseas and in other cases the entire gun was made overseas under license from Remington. The majority however, appear to be of Remington manufacture. Barrel lengths for rifles vary from 30" to 39" and for carbines from 19" to 22". Remington Marks appear in two or three lines on the tang. Caliber markings are not normally encountered. Foreign markings may include English, Chinese, Arabic, Turkish, Spanish and many others. The gun was officially adopted by denmark as their official arm in 1867, by Norway and Sweden in 1868, by Spain in 1869, Egypt in 1870 and Argentina in 1879.
To find out what caliber you have, you will have to do a sulphur casting of the chamber and have it identified by a gunsmith.