77 jap COTM

The 7.7x58 Japanese Arisaka

1Norma7.7JapA rimless military cartridge, the 7.7x58 Arisaka is ballistically and in form much like the rimmed .303 British. Both fire .311 bullets; both are “mid-length” rounds, longer than the modern .308 but shorter than the .30-06. The 7.7 arrived in 1939, however, more than 50 years after the .303. The first .303 loads featured a compressed 70-grain charge of black powder, driving 215-grain bluff-nose bullets at 1,850 fps. In 1892, cordite powder replaced black, and .303 velocity was hiked to 1,970 fps. Twelve years later, on the eve of the Great War, British Ordnance adopted the Mk VII load, a 174-grain bullet at 2,440.

In contrast, the 7.7x58 Arisaka was developed as a smokeless cartridge by the Imperial Japanese Army and Navy on the eve of WW II. It came in two versions. The rimless case, designed for rifles, was loaded with a 181-grain bullet at 2,370 fps. A semi-rimmed, machine-gun version (which could be fed and fired singly in rifles but would not work through their magazines) hurled a 201-grain bullet at 2,380.  Incendiary, tracer, armor-piercing, even explosive loads followed the standard military ball. Near war’s end, the Imperial Army manufactured copies of the M1 Garand and barreled it for the 7.7x58.

The 7.7 replaced the semi-rimmed 6.5x50SR Japanese Arisaka, a cartridge developed in 1897 for a flawed rifle, the Type 30. In 1905 this shortest of contemporary 6.5mm military rounds was chambered in the Type 38 Japanese rifle, an improved Type 30 with the strength of a Mauser. Original round-nose bullets gave way to 139-grain spitzers at 2,475 fps. With the 7.7x58 on the drawing board, the Type 38 rifle was modified to accept it. As the Type 99 (or Type 38/99), this rifle would become Japan’s infantry arm. Still, the 6.5x50 Arisaka remained in service throughout WW II. Because production of 7.7x58 rifles didn’t meet military demand until late in that conflict, the 6.5 Arisaka saw most of the action. Its modest powder charge was almost all consumed in long barrels, yielding little muzzle flash – an advantage for snipers and during jungle engagements. This round was also used in machine guns.

Both the 6.5x50SR and 7.7x58 were Berdan-primed (the anvil integral with the case, flash-holes to either side). Rifling twist for the 6.5 was a brisk 1 turn in 7.9 inches. Twist for the 7.7x58: 1-in-9.8. Both cartridges were used against Japan when China captured rifles and ammo, then began loading the rounds to supply army reserves and local militias.

Japan’s move to the 7.7x58 put more power into battle rifles. Muzzle energy jumped from 1,890 foot-pounds to 2,260. The nearly-30-percent increase in bullet weight boosted penetration. Still, Japanese brass in charge of the Imperial war effort widely considered the 6.5x50 adequate for jungle fighting in the islands. There, the 7.7x58 was used largely in SR form, to feed “heavy” machine guns.2Norma7.7JpV

After armistice in 1945, many Type 99 and Type 38/99 rifles were destroyed or, with their ammo, dumped into Tokyo Bay. This may have been a fitting end for very late-production rifles – those hurriedly produced, with no heat-treating. Captured 99s so manufactured are best not fired, even with factory loads that hew to the modest 42,000 psi pressure ceiling of original military rounds. But thousands of well-built Arisaka rifles were brought home by returning GIs. Others turned up in quantity and sold commercially. Like the British SMLE in .303, Japan’s Type 99 and Type 38/99 in 7.7x58 have adequate power for North American big game at ordinary hunting ranges. The best of few commercial loads is surely Norma’s 174-grain softpoint at 2,493 fps. Here’s how it performs downrange, given a practical 150-yard zero:

7.7 Japanese Arisaka, Norma load, 174-grain Softpoint

                        Muzzle      100 yds.    200 yds.   300 yds.    

Velocity, fps        2493        2174        1879        1612    
Energy, ft-lbs      2402        1826        1364        1004
Arc, inches          -1.5         +1.3          -3.4        -17.8    
Sidebar: Why Arisaka?

Also called the .31 Jap, the 7.7x58 Japanese Arisaka was named after Colonel Nariake Arisaka, who, with firearms designer Kijiro Nambu, served on a commission in 1894 to find an alternative to the Murata bolt-action rifle then in use by Japanese soldiers. The Murata started life as a single-shot but grew a tubular magazine. This black-powder rifle was supplanted by the Type 30 for the 6.5x50SR Arisaka in 1897. Kijiro Nambu is best remembered for Japan’s autoloading pistols of the early 20th century. The first were chambered for the 7mm and 8mm Nambu cartridges, circa 1904.


1 – The 7.7x58 Japanese Arisaka appeared in 1939 with a 181-grain bullet. A semi-rimmed version with 201-grain bullet was loaded to the same velocity (about 2,370 fps) for machine guns. Norma’s softpoint hunting ammunition is Boxer-primed and reloadable.

2 – Firing the same .311-diameter bullets as the .303 British, the 7.7x58 is similar in form and ballistics. It was named after Colonel Nariake Arisaka, who steered Japan first to the 6.5x50SR, in 1897. Seldom seen in the woods, the 7.7 is still a worthy deer cartridge with Norma loads.

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