Gallagher Standard Model, .50 cal. percussion carbine.   Serial #17893, mfg. Richardson & Overman, Philadelphia, Pa.  Good condition.  Nice representative sample of a good Civil War carbine. 22 ¼” barrel has shiny bore with light pitting and strong rifling.  Barrel, receiver and lock plate have no remaining finish with surface corrosion.  Butt stock has very good original finish with correct patch box, butt plate and sling bar.  Lever action and percussion lock work perfectly.  Authentic Civil War relic!   Antique, can ship to your door.