The Mark I Enfield revolver, as it was termed after the arsenal where it was built, initially had the forward portions of the chambers rifled and the internal parts nickel-plated (both later eliminated.) The six-inch round barrel was rifled with the system of Scottish gunsmith Alexander Henry (of Martini-Henry rifle fame.) Overall length of the piece was 111⁄2 inches, and it weighed two pounds, eight ounces.

The Mark II Enfield revolver was adopted in 1882, a scant two years after the introduction of the Mark I (bottom). Both were a combination of features by American, British, and Belgian designers.

The top-strap portion of the frame was a separate piece and the foresight of a slightly angular configuration. Grips were checkered walnut, capped with an iron plate which incorporated a lanyard ring.

The cartridge designed for the gun had a 265-grain, .455 diameter hollow-based lead bullet propelled by 18 grains of black powder for a muzzle energy of 289 ft.-lbs. Overall length of the round was 1.47 inches as opposed to the .450's 1.14 inches. As bullet and case diameter of the two rounds was very close, it was noted by the War Department that .450 ammo could be used with the Enfield in an emergency.

In December of 1881, the "Cartridge, S.A. Ball, Pistol, Revolver, Enfield B.L. (Mark III)" was adopted. It differed from its predecessor in having a bullet diameter of .477 and a deeper hollow base inset with a clay expanding plug. The round was designated the .476.

In 1882, a second pattern of Enfield revolver was sealed. According to the War Department: "The main points in which this pistol differs from Mark I are as follows--the top strap is part of the body. The stock is not checkered, and is secured to the body by means of a stock-cap screw. A locking arrangement has been added to prevent the cylinder revolving accidentally when the pistol is in the holster. This is thrown out of gear when the shield [loading gate] is open. A cam on the shield locks the hammer when the shield is open, and so prevents accidental discharge of the pistol when it is being loaded. This pistol takes the same cartridge as Mark I."

The author's Mark II shot poorly, although that's not completely unexpected as its trigger is not exactly easy-shooting and its bore a bit oversize for the available loads.

In 1886, a Royal Navy lieutenant was killed when his Mark I fell from its holster onto its hammer, accidentally discharging a round. This caused, in 1887, for a further safety device to be added to the gun that prevented the hammer from being forced forward while in the rebound position. Guns with this modification were marked with an "S" on the left side of their frames.

Initially the Enfield was issued to the Royal Navy, Royal Irish Constabulary and the Canadian North West Mounted Police, as well as to troops in India and to several colonial governments. Unfortunately for the Mounties, some shipping glitches caused the guns to be sent without their proper ammunition, and they were forced to load their new Enfields with .450 for a time.

While it was remarked by many that the gun was a tad on the homely side, it was nonetheless acknowledged to be rugged and functional. The .476 cartridge's extra oomph was also appreciated, and the piece could certainly be cleared much faster than the Adamses, which relied on under-barrel ejector rods.