The 7x61 Sharpe & Hart (7mm S&H Super)
By Chuck Hawks
Philip Sharpe and Richard Hart developed the wildcat 7x61mm in the early 1950's. It was originally based on a French experimental 7mm cartridge that, I understand, Sharpe had encountered around the end of the Second World War. The 7x61 approximated the ballistics of the .275 H&H Magnum of 1912, but was based on a shorter case.
The 7x61 S&H wildcat got some favorable comments in the gun magazines of the time and became moderately popular. In 1953 Schultz & Larson of Denmark tried to legitimize the cartridge and started chambering their bolt action hunting rifle for a commercial version based on a shortened, blown out version of the .300 H&H Magnum case. Factory loaded ammunition was supplied for a time by Norma of Sweden. The belted version of the 7x61 is also sometimes referred to as the 7mm S&H Super.
The 7x61 S&H was and is a fine cartridge suitable for all North American big game, and it developed a small following. Its commercial popularity was limited by competition from the 7mm Weatherby Magnum, a more powerful standard length super 7mm that was already on the ground. The introduction of the 7mm Remington Magnum in 1962 was, commercially, the beginning of the end for the 7x61, which eventually reverted back to wildcat status.
The final version of the 7x61 uses a belted magnum case 2.394" in length. Rim diameter is the standard magnum .532" and base diameter just forward of the belt is .513", tapering to a diameter of .473" at the shoulder. The shoulder angle is a very sharp 44 degrees. Case length is 2.394" and overall cartridge length is 3.27". Bullet diameter is .284", the same as other true 7mm cartridges.
Norma supplied factory loaded ammunition for the 7x61 S&H. Their first offering was a 160 grain bullet at a muzzle velocity (MV) of 3100 fps with muzzle energy (ME) of 3410 ft. lbs. Later Norma introduced a 154 grain bullet at a MV of 3060 fps with ME of 3200 ft. lbs.
The trajectory of that load should look something like this: +2.5" at 100 yards, +3.0" at 150 yards, +2.3" at 200 yards, and -3.0" at 300 yards. Incidentally, that trajectory is practically identical to that of the 7mm Rem. SAUM, introduced about 50 years after the 7x61.
Handloaders can essentially duplicate the old Norma factory loads, and have access to bullets of lighter and heavier weight. The fifth edition of the Hornady Handbook of Cartridge Reloading shows 7x61 S&H loads for their 139, 154, 162, and 175 grain bullets.
For plains or mountain hunting of medium size big game a 139-140 grain spitzer bullet would seem an excellent choice. According to the Hornady Handbook their 139 grain SST boat-tail spitzer bullet can be driven to a MV of 2800 fps by 57.8 grains of H4831 powder, and a MV of 3200 fps by a maximum load of 65.0 grains of H4831. The trajectory of that bullet at a MV of 3100 fps looks like this: +2.5" at 100 yards, +2.3" at 200 yards, -2.5" at 300 yards, and -6.9" at 350 yards. The maximum point blank range (+/- 3") is 305 yards.
For hunting heavy game the Hornady Handbook shows that their 175 grain Spire Point Interlock bullet can be driven to a MV of 2500 fps by 53.9 grains of H4831 powder, and a MV of 2900 fps by a maximum load of 62.5 grains of H4831. The latter load has a ME of 3267 ft. lbs., and at 200 yards the numbers are 2507 fps and 2441 ft. lbs. The trajectory of that load looks like this: +2.6" at 100 yards, +1.9" at 200 yards, and -4.1" at 300 yards. The maximum point blank range (+/- 3") is 287 yards.
The 7x61 Sharpe & Hart never became very popular in the U.S. (although I understand that it was moderately popular in Canada), and it is rarely seen today. Yet it has always gotten favorable mention in the firearms press. I can see no reason to build a rifle in 7x61 caliber when the later 7mm Remington Magnum is so widely available, but the 7x61 S&H was one of the best of the magnum wildcats, and for a time it had a chance at commercial success.
Copyright 2003, 2012 by Chuck Hawks. All rights reserved.