Tuesday, January 10, 2012
7.7 Japanese loading....
You won't often see this brought up anymore but some folks still buy ammo and shoot the guns and some folks still try to load it. Bullets are easy, the commercial product for the .303 Brit works just fine, you can even use .303 Brit loads as data. Brass can be a problem though. Most people start with .30-06 brass, often it is once fired (sometimes several times fired). Use this brass with a case head nominally .025" smaller in OD in a larger than average chamber, pressures in the 40K+ PSI range, add in the factor of the brass being work-hardened and you might have an instance of cases splitting at the head. Not desirable.
With the head diameter of 7.7 mm type 99 chambers often exceeding .487", I fail to see how any commercially available ammo is much better than that formed from new 30-06 (or similar head size) brass. A lot of what I see published about the 7.7 Japanese round seems based on second-hand reports and not on actual research and experience.
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