In 1920 Holland and Holland brought out their .300 Magnum cartridge, based on the .375 case necked down to accept .308 inch bullets, which is called the .300 Belted Rimless Magnum or H&H Super .30 in Britian. The .300 H&H case has been the basis for most of the magnum cartridges designed since. The traditional British factory load drove a 180 grain bullet at a muzzle velocity (MV) of 2750 fps with muzzle energy (ME) of 3020 ft. lbs.

The .300 H&H is obsolescent in America, having been replaced by the shorter, more powerful (as factory loaded) .300 Winchester Magnum. For many years the standard .300 H&H factory load in the U.S. listed a 180 grain bullet at 2920 fps. Recently that muzzle velocity has been reduced to 2880 fps. The muzzle energy of the current load is 3315 ft. lb. At 200 yards the figures are 2380 fps and 2260 ft. lbs.

Handloaders can easily and safely exceed the performance of the typical factory load. For the handloader, the venerable .300 H&H Magnum gives away nothing to the newer short and standard length .300 Magnums, and it is superior with the heavy 220 and 250 grain bullets. According to the Barnes Reloading Manual No. 1 their 180 grain bullets can be driven to a MV of 2904 fps in front of 65.0 grains of RL19 powder, and a MV of 3091 fps in front of 69.0 grains of RL19.

The .300 H&H can exceed the maximum velocity of the .300 Winchester Magnum by about 75 fps with the 250 grain Barnes bullet in front of a maximum load of 67.0 grains of H4831 powder. This load in the .300 Holland gave a MV of 2,650 fps vs. a MV of 2,574 fps for the top load with any powder for the .300 Win. Mag.

Note: A complete article about the .300 H&H Magnum can be found on the Rifle Cartridge Page.