The Model 99 was preceded by the Model 1895, which was the first hammerless lever-action rifle. The 1895, as well as the later Model 1899 and early Model 99, used a six-shot rotary magazine to hold the cartridges. The rotating magazine uses a spring-loaded spool with grooves to hold the cartridges. The Savage 1899 took advantage of the spool to include a counter to indicate how many shots are left. The Model 99 continued using this system for many years, until its replacement with a detachable magazine.
The rotating magazine design allowed the rifle to be one of the first lever-action rifles to use spitzer bullets. Previous lever-action rifles used tubular magazines, which placed cartridges of ammunition end to end. The pointed tips of a spitzer bullet would touch the primer of the cartridge in front of it, possibly causing an accidental discharge. Another novel safety feature was that, upon cocking the rifle, a small pin would protrude above the top receiver to indicate the rifle was cocked and ready to fire.