72,076, issued on December 10, 1867) obtained by Peabody was on an action system specifically designed and constructed for use in converting military muzzle-loading muskets into breech-loading arms.

By the end of the American Civil War, the self-contained metallic cartridge was a sure thing; conversions of muzzle-loading rifles had already commenced and it seemed to be a profitable venture to get into.

Peabody developed such an action based on his original idea of the rear-pivoted breechblock, for use with Springfield and Enfield muzzle-loading muskets.

The receiver is largely composed of two long narrow walls connected at the ends by thicker blocks of metal.

The front end is bored and threaded to accept the barrel, while the back forms a tang to fill the recess in the musket stock left after the removal of the breech plug.

The top tang part of the receiver is grooved to make room for the tail-piece so that only the very end is above the grip line of the stock.

With no money to buy new breech-loading rifles, the Serbian government chose a cheaper solution: to upgrade some old muzzleloaders to breechloaders, using some of the existing conversion systems.

[6] At the same time, as early as 1866, Serbian military experts chose the very cheap British Green brothers' system for the conversion of small-caliber muzzleloaders to breech-loading rifles.