T38 Experimental 7.7 Rifle No. 31 & Korean T99 - U S Cal 30. Conversion

[riceone]

T38 Experimental 7.7 Rifle No. 31

With experience gained by the use of the Type 92 Machine Gun in Cal. 7.7 the Japanese War Department decided a larger caliber was needed for the infantry rifle. The needed a rifle round with greater impact for the foot soldier.

In 1938 guidelines were established to develop a 7.7 rimless cartridge for both rifles and machine guns. For the testing some 300 rifles were modified at Kokura Arsenal to test the new cartridge. A new barrel in cal 7.7 with rear sight graduated to 2000 meters was installed on the T38 actions. The receiver had some machining to accept the longer cartridge and the magazine box was lengthened. A recoil lug was installed in the stock to strengthen it for the added recoil.

After testing of two rifle and two carbine based on T38 action it was decided to design a new rifle which became the T99. Information gained from Military Rifles of Japan.

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Korean T99 - U.S.Cal 30. Conversion

When the North Koreans invaded South Korea in 1950, the US sent troops and weapons to South Korea. American weapons were too complicated and stocks too long for the small frame of the Korean soldier. Under the supervision of the U.S. Ordnance some 133,000 Japanese rifles were pulled from stores in Japan and modified to fire the 30-06 cartridge. Tokyo Arsenal was chosen to do the modifications. The chamber was reamed to 30-06 dimensions. The magazine box was lengthened and receiver machined so that stripper clips could be used to load the rifle. A "U" shaped notch was milled in the front top of the receiver to facilitate the longer cartridge. "U S Cal. 30" was stamped on the left side of the receiver just in front of the serial number. Information was taken from Military Rifles of Japan.

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Information

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[Stevo]

Very interesting, especially the .30-06 T99. Thanks!

[Claven2]

Isn't the .30-06 case base on the small side fo a 7.7 chanber? I've made 7.7 from Lake City .30 brass, but typically I got relatively few reloads from it since you get large base bulges.

Perhaps on virgin brass it's not an issue?