Rear end of Groove (1864),
showing Stop for Projectile.

The powder-chamber is cylindrical, of the same diameter as that of the bore across the grooves. The bottom groove is produced through the powder-chamber, to serve as a directing groove for the projectile in loading.

In rear of the powder-chamber there are two gas-check seats, conical in shape, with the small diameter forward. The rear and larger one is intended for service in case of accident to the other.

Gas-Check (1864).

Breech-Block (Section).

The breech-plug seat is similar to the model 1870.

The breech-closing mechanism consists of two main parts like that of the model 1870, the breech-plug and the console or bracket.