(Sixth Edition Handloader's Digest
Edited by Jonh T. Amber
Editor of Gun Digest. )


I have an old handloader's digest, and it had a section about 8mm Nambu. I desided that I would share the info for people who haven't found those place on the net that have the info.

Handload the 8mm Nambu.

By Larry S. Sterett

Tucked away in dresserdawers or hanging on the wall in many homes are souvenirs from the Pacific Theatre of Le Guerre II in the fomr of the Japanese Pattern 14 or Model 1925 automatic pistol, commonly known as the Nambu Modified from the original Nambu design, the 1925 model may be seen with the round trigger guard or an enlarged cold-weather guard; it may have a knurled, solid, round bolt knob or a grooved knob with flats on top and a bottom; even the grips will vary slightly. The caliber remained the same . All of the Nambus, except for the 7mm baby version are chamber for the bottlenecked, solid drawn-brass semi-rimmed, 8mm Nambu Cartridge, unheadstamped.
The original 8mm Nambu cartridge is quite unlike any other pistol cartridge. It resembles the 7.65 Luger, except for being larger and useing a slightly heavier bullet--the Nambu cartridge has a total weight of approximately 159 grains. The case carries a brass berdan-type primer cap, filled with .12gr. of detonating composition.
The bullet has a lead alloy core and a cupronickel jacket. Aaverage bullet weight is 100 grians, with ranges from 98 - 102 grains being noted. Lenth of the full-jacket bullet is .59-inch.
The propellant consists of 4.63 grains of %95.2 nitrocellulose and %4.8 diphenylamine powder, a load that fills the case. Two differant-colored powders have been noted-one ash-colored and one a pale yellow With both being the same approximate size 0.05 x .0.05 x 0.04. Velocity of this military load from a 4.56 inch barrel averages 1066fps.
Surpluse Nambu ammunition has never been on the market in shooting quantities, nor were any of the pistols ever liberated in large numbers. For this reason very few of the Nambu pistols have been shot extensively, although many of their owners have wanted to do so.
Two such owners- Robert E. Bard and Osborn Klavestad- with the backing of several others-formed the B&E Cartridge Company of Minneapolis, Minn., in 1948, with the specific purpose of manufacturing one caliber of ammunitions-8mm Nambu. Since it was necessary to keep the initial costs of the company to a minimum the production of the cases was 10-foot lenths of navel brass rod were fed into a 6-spindle screw machine which cut and shaped a complete amounted to 720 cases per hour. The cases were not annealed as in regular deep drawn case manufacture by the large ammunition companies, but it was not necessar. Drawing work-hardens the brass and it has to be softened to prevent cracking. However the B&E cases were turned rather than drawn; work-hardening did not occur and the annealing step could be skipped. Further, the cases would not be subjected to extreamly high chamber pressures and would be capable of handling regular pistole pressures as manufactured.
The completed cases were then taken to a basement workshop for priming with regular small pistol pricmers (Boxer type), powder charging, and bullet seating, using more or less conventional automatic loading equipment. There were no Japanese powders available, so the B&E firm started from scratch using American powders. Load after load was tested before finally arriving at what was considered to be a suitable charge.
Faced with the expense of having special bullets made to order th B&E firm desinged their own based on the Nambu desing, and set about manufacturing them in a punch press. Slugs of lead wire were cut and formed in a die in the press plated with a copper alloy to improve appearance and provide a slightly harder surface. the bullets-weighing about 95 grains were then loaded into the charged cases via the altered punch press and the result was a complete american manufactured 8mm Nambu cartridge.

(dimensions of the Japanese 8mm Nambu Cartridge taken from a previously restricted ammuntition identification guid issued by the British arsenal at Kirkee, )

The case head of the Minneapolis produced cartridge is headstamped B NAMBU E MPLS. As might be expected, these cartidges were never too p lentiful and most were rapidly picked up by the collectors. Whatever happened to the company itself isn't known to the author, but if it were revived it should do a fair amount of business.
The summer of 1963 almost saw the Nambu cartridge problem solved; this time by the two Connecticut firms. Watertown Shooting Supplies, Watertown Conn., took the 41 Long Colt Case, removed the rim and turned a new extractor groove. The result, when resized and trimmed, was a case almost identical to the orginal Nambu. Although more expensive than the other altered cases to be mentioned later the 41 case is a much better fit in the Nambu chamber and the reloading life is longer. the Waterton fimr apparently dropped the project shortly thereafter, but the job of alteration is not outside the scope of the average handloader whit a drill press or a lathe. Handloader with a drill press or lathe. there is anothe catch; manufacture of the 41 Long Colt cases has been discontinued, although supplies may still be available from some dealers.

(finish later with rest, there's a lot to type so I'll finish it tomorrow.)

(Sixth Edition Handloader's Digest
Edited by Jonh T. Amber
Editor of Gun Digest. )