When the Lee magazine rifle was adopted for British military service, it was initially produced as a long rifle for the infantry. To accommodate the cavalry on horseback, a much more compact carbine version was produced. These were initially Lee Metford pattern, but changed to Lee Enfield pattern rifling when the long rifles made the same shift. The carbines were the origin of the cocking-piece-mounted safety, as the Lee Metford rifles in service at the time had no manual safety at all. The cavalry service wanted one, and the safety they came up with was added to later patterns of infantry rifle.

The Lee carbines are designed to be sleek and handy, to easily fit into a cavalry scabbard. The bolt handles are swooped forward slightly and flattened against the receiver. The front sight wings are rounded and the magazine was reduced to 6 rounds, barely extending beyond the receiver. Early examples were fitted with a D-ring on the left side of the receiver socket for use with a single point sling, but this was removed quickly and it is very rare to find carbines with intact sling rings today.