U.S. MODEL 1866 ALLIN CONVERSION RIFLE "SECOND MODEL ALLIN - TRAPDOOR" Description
.50 centerfire cal., Civil War lock marked with "Springfield" and dated "1863" or "1864", 40 in. Civil War barrel with three bands with band springs, front sight doubles as lug for angular bayonet, iron mountings, bright metal finish with case colored lock, blued rear sights, breech block marked "1866" over American eagle. RF=1.
Designed by Erskine S Allin. Altered at Springfield using Model 1863 percussion musket. Changes made from Model 1865 involved lengthened bolt, firing spring, and strong internal extraction system.