RIA: Japanese 8mm Hamada Pistol

Just as production of the .32ACP Type Hamada pistols was reaching full scale, Bunji Hamada was asked to redesign his pistol to use the standard 8mm Nambu cartridge. This he did, and after several changes required by the Army (which appear to have had more to do with giving the Army some claim to the design rather than for any practical reasons) it was adopted in 1943.

Production of the .32ACP pistols continued uninterrupted, while a defunct textile factory in Notobe was renovated to become the production plant for the new Type 2 Hamadas in 8mm. Machinery was provided by the Torimatsu factory, and the guns were to be sent to Torimatsu in the white for final finishing operations.

While several thousand were made according to surviving records, the only ones still known in existence today have serial numbers between 2 and 50 and are still in the white. This suggests that aside from a small initial (sample?) batch, all the Type 2 Hamadas were destroyed or lost – possibly by aerial bombing or during transit on the ocean.


  1. This pistol looks redesigned for the ease of manufacturing and also using a much powerfull round. There seems no similarity in trigger/sear/disconnector engagement with Browning patents and take down connections seems also simplified. All areas from side walls of the frame and the slide and its top suiting to shave metal, seems hollowed out to get a lighter handgun which should have been demanded by the army which preferred carrying a light personal pistol everytime than some seldom recoil punch at the hands. The front of slide seems preferred as guided by the frame rails instead of sole barrel in 7.65mm Model which should be a measure against to the heavy recoil vibration to happen inside the tube to ruin its guiding effect by cause of bottlenecked round used in a straight blowback gun which needing a locked breech. It seems that only unchanged element in this new gun than the old model, being the barrel mounting method. Very interesting handgun of Japanese origin.

    • The deep scalloping at either side of the slides rear is reminiscent of the BSA prototype .34 &.45 cal pistols which were also striker fired, it’s trigger blade/guard and immediate area have apparent similarities as well I think, externally at least in regards there shapes.

      • Good finding. However, Mr. Hamada should not be awared of BSA’s prototypes. In fact, these areas should be the easiest to shave off metals if reducing weight is demanded. In hammer firing types,
        Savage and Astra might be examples of having similar semi scalloppings at those sections. Most distinctive feature of Hamada pistols might be the slide upright back which should be a necessity of the take down method they use.

        • On the face of it, he probably wasn’t aware of said prototypes. Although it’s not impossible, they predated WW2 seemingly by around twenty years. As an arms manufacturer, he might have had some contact with BSA in peacetime… Perhaps they tried to sell Japan the new “belted ammo” as a concept around the time of it’s development. The Hamada and the BSA have trigger guards with a rise on there underside unlike a FN1910 “the pistol most widely attributed to being relevant to both designs” presumably to facilitate a higher grip via finger clearance. The pin above the trigger blade is also more similarly located on the BSA and Hamada, than the 1910, which corresponds with there respective similar trigger blades as oppose the 1910. This is apparent, even without the similar scalloping aforementioned.

          The .32 BSA model has a more 1910 style trigger guard unlike the others but curiously, at least to me, its rear in particular resembles the Hamada .32 more than a 1910 in that it’s slide a that point appears somewhat squared…

          The Hamadas take down, is not found on either BSA clearly, but that’s a strange mechanism in of itself, they went to the trouble of making the top of the slide down tab thing resemble the rear of a striker or it’s frame mount I.e. It’s circular, for no purpose other than atheistic similarity. Which suggests copying, for copyings sake did take place which may be relevant in regards the scalloping.

          • Well on the .32 Hamada, the strikers frame mounted stopper is round, so the applicable part of the slide down piece matches this although it doesn’t need to asthetics aside, on the 8mm version the stop doesn’t appear to be round but they have kept the same shaped slide down piece. The .32 Hamada doesn’t have the trigger guard rise, like the BSA .32 unlike the other BSA’s and the 8mm Hamada. Possibly a coincidence…

          • Actually the .32 Bsa does have the same trigger guard, as the .34… It was converted from it, must have got confused looking at 1910’s. But the other points are valid, he he.

          • The .32 doesn’t have scallops though, like the Hamada .32 were as the .34 belted does, they kept the scallops on the .45acp… The .45 was locked, but the .34 wasn’t. Interesting anyway.

          • Interesting. You may be right. But, might it be a reflection of weight reducing approach seen in Hamada 8mm pistol as extended to the trigger guard and frame joining section at underside.

            Regarding to the Hamada take down, it seems logic and practical to me. The circular top of dismount bolt resembling a doll’s head is the thing retaining the backwardly moving slide in its place over the receiver when its arriving and passing through the dismounting region.

          • .34 Belted, might be partially similarly sized/ballistically similar to 8mm Nambu… So given a blowback design in Nambu was required, perhaps they did know of the .34 Belted and copied it’s slide weight amongst other things because that was blowback in essentially the same calibre to speed up the development of the design. “Regarding to the Hamada take down, it seems logic and practical to me. The circular top of dismount bolt resembling a doll’s head is the thing retaining the backwardly moving slide in its place over the receiver when its arriving and passing through the dismounting region.” Oh, you mean like a guide I.e. Said shape passes into the corresponding shaped firing pin channel? I thought it actually dropped lower than the frame, and the spring mount is attached to the frame… I still think that actually, I will have another look.

          • The other 8mm Nambus are locked aren’t they, perhaps that explains the belted idea. They figured that was the way to reliably reduce the need for a lock without vastly increasing the size of the slide via supporting the case during blowback initially by a reinforced case, maybe the Japanese increased the slide weight or this 8mm blowback had issues, alternatively they managed it without the belt making it a defunct notion. Or it just isn’t related. Yes it could be simply weight reduction, of the frame… It does look very similar though that area of the 8mm pistol to the BSA, more similar than a 1910 clearly it might have been a domestic development and merely a coincidence.

          • Just as you meentioned. The doll’s head fits into the striker tunnel and guides the slide rearward travel all the times except being pushed downward for take down. In fact, in 8mm
            Hamada, the frame post on which that doll’s head propped, seems unnecessary.

          • 8mm Nambus which being all locked breech, seem as made for real field use, whereas these Hamadas looking as made for headquarter officers needing seldom use of their handguns.

          • It’s a separate piece that drops below the frame, 10.50 sec on the .32 Hamada video, and 12.05 sec on the 8mm one, the shape of the actual frame mounted spring stop is replicated on said piece on the .32 but on the 8mm the spring stop is square yet the takedown piece retains the same shape as that on .32 itself not acting as a guide in the manner you assert because it drops below the frame, the guide is instead the stop thus it is asthetic in regards the cut out for it on the slide is not of a corresponding shape. Regardless of use, surely the design would need to function correctly with It’s respective cartridge you either need a lock or you don’t.

          • Thought the take down process seeming same, the 7.65mm Hamada’s looks based upon guiding the slide rear travel by both frame post and take down bolt, 8mm Hamada’s based on solely by the take down bolt. When that take down bolt is drawn downward and the slide is taken to the take down region, 8mm’s frame post is free to pass through the narrow channel at bottom of the striker tunnel, whereas the 7.65’s having a square shaped recess for this purpose during the slide rear portion is taken upward for initial takadown. 8mm belted Nambu round would deserve a locked breech actually, but in absence of this facility, its case seems in enough durability to bear the excess pressure inside. However, the violently recoiling slide would beat both the frame, itself and the user through this setting but, it seems an officier needing to use a handgun not so often, could bear such an uncomfort.

          • Interesting takedown method, I think you understand the intricacies of that better than I currently. I think .34 Belted may well have fired a Nambu sized bullet, given the Nambus neck is .34 perhaps it was based on .320 British revolver but lengthened somewhat and given a belt as oppose being bottled necked- So it was more powerful than .32acp, more .380 mind you .380’s don’t need to be locked without having overly large slides so I assume 8mm Nambu is slightly more powerful than .380 in which case .34 belted is probably similar and thus they came up with the belt as oppose using a lock without increasing slide mass perhaps.

          • The magazine on the .34 is longer than the .32acp version. Like you say “This pistol looks redesigned for the ease of manufacturing and also using a much powerfull round.” In that, it’s easier to manufacture a blowback design.

            Pity we can’t see the BSA’s trigger mechanism, perhaps given you don’t think the Hamada is Browning based there might be some similarity to the BSA who knows.

          • Thank you Strongarm, for the input.

            And in regards the disassembly method when you say:

            “When that take down bolt is drawn downward and the slide is taken to the take down region, 8mm’s frame post is free to pass through the narrow channel at bottom of the striker tunnel, whereas the 7.65’s having a square shaped recess for this purpose during the slide rear portion is taken upward for initial takadown.”

            You mean the round part of the frame mounted striker stop on the .32acp is held in the slides striker channel as is this correspondingly shaped part on the take down lever, but the cut out enabling disassembly I.e. The narrow channel, is only wide enough to enable the striker stops round shape to pass when the slide is aligned. So if the disassembly lever was up the two circles would be to wide to pass hence why it doesn’t disassembe during firing… Well worked out, I can see what you mean, if that’s what you mean he he.

            On the 8mm version, the frame mounted striker spring stop isn’t round… Now, if the narrow channel aforesaid was only wide enough for the disassembly pieces circle- This part of the disassembly piece riding within the striker channel like a guide when firing, it would disassemble similarly… In the absence of the other circular piece, by virture of there not being any piece… Perhaps there’s no narrow channel then on the 8mm they simplified it- If the disassembly lever is down theres nothing riding in the striker channel thus holding the frame to the slide “the disassembly piece being attached to the frame” when the slides interrupted grooves align with gaps in the rails it enables you to pull off the slide.

          • I think you nailed that, I really couldn’t see what lowering the lever did to enable disassembly. I was going to say the part on the 8mm termed the out of battery thing… May actually be a slide stop, that could only be lowered when you dropped the disassembly lever therefore enabling you to line up the groove/rail gaps in the slide and frame to facilitate disassembly however I couldn’t see that part on the .32acp, so the shape of the disassembly piece isn’t asthetic it’s integral to disassembly as you initially thought on both models.

          • Hmmm, so on the 8mm, when the slide is fully forward the slide is actually only held onto the frame by rails until you pull the slide back with the disassembly lever up which essentially acts as a further rail preventing disassembly, clever.

          • That explains why on the .32 Hamada you have presise slide disassembly alignment points marked on the frame, and on the 8mm you don’t. Because your lining up the fixed to the frame keyhole shaped piece “the striker spring stop” which is running inside the striker channel, with the cut outs for it inside said channel which facilitate removing it from the channel in so doing releasing the slide from the frame. On the 8mm the only key hole shaped piece is part of the disassembly lever which isn’t engaging the striker channel because it’s been depressed prior to pulling the slide back to a point were the frame rails and slides grooves are free of each other via them being interupted. You simply wiggle the slide a bit after pulling it back slightly and likely enough after some practice you’ll be in the correct spot as it’s a larger area.

          • Well outlined Pdb, if briefly said, slide backward movement at rear is guided combinely by frame rails and take down bolt with exceptions, on slide foremost position, by frame rails only and at both slide and frame on take down zone, by take down bolt only. If take down bolt is lowered and slide and frame at take down zone, the pistol will be ready for happening called as field stripping. At 7.65 model, frame rails also get aid of frame mounted striker spring rear guide post.

          • Exactly!:) I have been thinking, that to get the maximum benefit from the Hamadas disassembly method it would be best incorporated into a design that enabled it to deliver a pistol with a low profile. On the Hamada, the barrel due to it’s innovative attachment method is quite high which raises the overall profile of the pistol in regards it’s height.

          • The interupted thread, twisting barrel/bushing attachment/disassembly method gives a low profile to a pistol. You could perhaps use the Hamadas disassembly method in conjunction with say a FN 1910 barrel, to lower the profile further. You wouldn’t need a bushing, as per the Hamada. And as you wouldn’t need to rotate the barrel, the lugs would simply stop the barrel from moving backwards/forwards via them engaging cuts in the bottom of the frame preventing rotation. This could enable the slide rails on the 1910, to instead run along the edges of the frame. Adjustments for the lower feed ramp would be needed, and the position of the strikers spring stop would change. But doing this essentially drops the height of the pistol, by the height of the 1910’s slide mounting blocks via using the Hamada method of disassembly.

          • They might not have done this originally, because it would make the magazine so grip longer. Or something to do with the feed ramp, or they wanted to use there own style of barrel and weren’t particularly out to lower the profile. Nowadays people are though, for ccw.

        • Uh, revolvers generally take more time to load unless you get moon clips. And semiautomatic pistols are generally easier for detectives to conceal on their person.

      • Chamber it for 9x18mm Ultra and use the original 8 shot magazine capacity instead of the Japanese army mandated 6 shots, and we’re in business.

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