Joslyn Model 1864, .52RF cal. single shot carbine.   Serial #4201.  Good condition.   22” barrel has worn bore with some pitting, decent rifling.  Barrel has correct sights, sold brown finish, surface corrosion behind muzzle.  Lock plate and hammer have old brown finish with crisp address markings.  Later style pull-out breech block release.  Walnut stock has very good finish with light handling marks.  “US” stamped butt plate.  Saddle ring present.  Action works fine.  Important Civil-War era carbine!   Antique, can ship to your door.