Based upon the well-proven
.375 H&H Magnum rimless belted big-game cartridge case heavily necked down, the .244 H&H originally fired a , aluminum-jacketed, copper-pointed bullet pushed by of non-cordite smokeless (nitrocellulose) powder, and returned a
muzzle velocity of about . That load and velocity remain standard for the commercially loaded cartridge today; although handloaders can achieve higher velocities with careful load tuning. The .244 seldom performs well in barrels less than long, owing to the need for a longer bore to allow pressure and bullet velocity to reach intended levels. Lloyd was unable and unwilling to embark upon commercial cartridge production, and consequently "gave" the cartridge to veteran London rifle and ammunition makers
Holland & Holland Ltd., who in 1954 had paid him £250 towards his cartridge development costs. H&H quickly adopted it, the cartridge acquired the prestigious "H&H" appellation, and both H&H and David Lloyd went on to build significant numbers of very high quality bolt-action
deer-stalking rifles in .244 H&H Magnum calibre (see
Lloyd rifle). Initially, commercially loaded ammunition was manufactured by
IMI Kynoch at its
Birmingham, England factory. Commercially, this cartridge has only ever been loaded with bullets: lighter- and heavier-bulleted loads have been created by
handloaders. Chuck Hawks, a prominent US commentator on rifle cartridges, opines that, "the .244 H&H Magnum represents some sort of high water mark in the development of the 6 mm cartridge. To use an aviation analogy, you could think of it as the Concorde of rifle cartridges."
David Lloyd, the .244's originator, went on to develop a still more powerful prototype round by reducing the case body taper and increasing the already large power capacity to produce the "David Lloyd 6 mm Magnum". His hope was to use bullets heavier than the .244 H&H standard ; but this cartridge was never commercially produced, and only two prototype
Lloyd rifles are believed to have been chambered for it. In the early 1990s British fieldsports author and ballistician Colin McKelvie had a custom rifle built on a BRNO CZ Magnum action, with a .244in Border Barrel with a 1:7 fast twist. Using handloads with
very-low-drag (VLD) .244in hollow-point bullets of , accuracy of 0.63
MOA was achieved, with average muzzle velocity of 3,630 ft/s (1,106 m/s) and acceptable chamber pressures. This level of performance is what Lloyd had sought with his "improved" .244 H&H Magnum. ==Controversy==