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 While the belted .244 H&H Magnum could be considered the velocity/energy pinnacle of 6 mm/.240in cartridges, that power comes at the cost of significant muzzle blast, as well as shorter-than-average barrel life; in addition to which commercially loaded ammunition is expensive. Because of these drawbacks the cartridge never came into widespread popularity, and has never been offered as a chambering by any of the mass-market riflemakers. The .244 H&H rather fell by the wayside in favour of 6 mm rifles in the same general class such as the .240 Weatherby Magnum (for which it had been an inspiration to designer Roy Weatherby), and also the various 6.5 mm Magnums. The .244 H&H still has its adherents, however, and occasional rifles are still chambered in this caliber by Holland & Holland and others. Ammunition is still made for Holland & Holland and used cases can be handloaded. See also List of cartridges by caliber List of rifle cartridges 6 mm caliber References External links .244 H&H Loading data at Reloaders Nest 244 Holland & Holland Magnum at Accurate Reloading Pistol and rifle cartridges Holland & Holland cartridges British firearm cartridges