format_quoteFirst tested in 1919, the 7.7×58mm was chambered in the Type 99 Arisaka in 1939. This came too late for Japan to standardize on this as a single battle-rifle chambering for use in its expansionist war efforts. This caused Japan significant grief. As is well documented, it delayed and complicated many of Japan’s Military excursions throughout WW-II.
The 7.7 uses a 0.312-inch bullet.
Myths abound around the 7.7×58 and why Japan designed it to be so similar in design to the 30-06 Springfield.
When I was eight, the 7.7×58 came up in a conversation my father and several of his brother’s-in-law were having while talking about the War and the guns they had seen.
Dad told a story an Officer had told him and others. That Officer claimed Japan had designed the 7.7 by copying the 30-06 and making the case and bullet just enough larger so 7.7 ammunition would not fit in 30-06 rifles but 30-06 ammo would fit and function in 7.7 rifles.
His claim was that Japan had thereby created a situation where it could use captured U. S. 30-06 ammo but the U. S. could not use captured Japanese 7.7 ammo. Of course, this was nothing but ridiculous nonsense. Not knowing better, Dad believed it. Many decades later, as I was writing Cartridges of the World, 8th Edition, I recalled Dad’s telling of that story.
I later explained to Dad why the 7.7 would not fit in a 30-06 and the 30-06 would not fit in a 7.7. The story he had been told was total nonsense. This is the nature of gun legends; much has been made of mere drivel as had happened with what that officer had told dad and others.
What the 7.7 was, was Japan’s attempt to solve a problem. The 6.5×50mm Japanese had proven inadequate, just as the 6.5 Carcano had.
Because of a 45,000-psi pressure limit, handloads held to SAAMI standards will not match performance of the 30-06. I suspect this extremely limited pressure specification reflects nothing more than cultural bias.
The only reason Japan might have loaded the original Military ammunition at such modest pressure, see closing comment, would have been concerns over use in unusually hot environs and very early in the smokeless-propellant era Japan was deeply involved in testing smokeless rifle propellants at different temperatures. This suggests the propellants Japan was using might have been unusually sensitive to temperature.
Certainly, no other good reason existed for Japan to use such modest load pressure because the Arisaka Type 99 was, by far, the strongest WW-II battle-rifle adopted by any country, as Parker Otto (P. O.) Ackley proved in destructive testing. I suspect the ammunition Japan loaded for Military use generated pressure closer to 58,000 psi.
While this seems to be a very well-kept secret, the Japanese produced phenomenally accurate 7.7 Arisaka Sniper rifles. These used chrome-lined bores. My late friend, Craig Coburn, owned one that would shoot Norma factory loads into a tiny ragged hole at 100 yards until he ran out of ammo!
Modern barrel makers have routinely claimed chrome bore-lining always significantly degrades accuracy. The 7.7 Arisaka Sniper rifles would seem to contradict this claim. Evidently it is possible to chrome line a bore without significantly compromising accuracy; likely very expensive to do, but possible. If Norma could make such accurate 7.7 ammunition, you can too!
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