Test barrel length: 28 Source(s): Kynoch Ammunition.
The .240 Magnum Rimless Holland & Holland (also known as the .240 Apex and the .240 Super Express) and the .240 Magnum Flanged are a pair of centrefire sporting rifle cartridges developed in English gunmakers Holland & Holland in the 1920s, primarily for use in hunting deer and plains game.
The ballistic performance of the .240 H&H in factory loads is very similar to that of the .243 Winchester, with a 100-grain (6.5 g) bullet with a diameter of .245 inches (contrary to the .240 name) giving a muzzle velocity of approximately 2,900 feet per second (880 m/s). When it is loaded at the same pressure as the .243 WSSM using modern powders, the .240 H&H has the potential for slightly better performance.
Most bolt-action rifles made for the .240 H&H will be amply strong enough to handle handloaded cartridges at high pressure.