7.7 Jap question


#1

Hi Folks , this is a new one on me ,a 7.7 Jap ? rimmed with no headstamp ,brass primer, green primer seal and 3 primer crimps like its 6.5 little brother ,FMJ bullet ,looks like a later production round ,do we know when made and for who ??? thanks Randy


#2

Hi,

I don’t think anybody will be able to tell you exactly who made your 7.7 round because the lack of a headstamp on Army rounds is the norm. The cartridge may have been made sometime between 1939 to 1945 according to my sources which coincides with the years of production.

Identification of the Japanese cartridges can be very confusing and I cannot say I have a clear understanding since there seem to be contradictions in identification which often come up.

If I am not mistaken, the 7.7x58 round came in two flavors - a rimless and semi-rimmed version and these were used by the Army. There was also a 7.7x56 rimmed version almost identical to the 303 British, made specifically for use by the Navy.

If your cartridge is the rimless or semi-rimmed Army variety the green primer sealant is just primer sealant and does not indicate the function of the round. Army cartridges used a color band around the case mouth to designate functional type. I have several of these and they are sometimes difficult to differentiate because the colors have faded. The three stake primer crimp is also very characteristic of the Japanese WWII era 7.7 Army ammunition. I have about a dozen of these in my collection and while they may have been made by different arsenals they all look alike. The bullets on these rounds are even different but I won’t get into that.

If you have a true full rimmed 7.7x56R this would be the Navy cartridge. Usually the Navy cartridges were headstamped. To make things more confusing the Navy used primer annulus color to designate the functional type.

From your description of no headstamp and a 3 stake primer crimp, I am guessing that your round is an Army 7.7x58 semi-rimmed ball cartridge, but I stand open to correction.

Heavyiron


#3

Hi Heavyiron, thanks for your reply I have a good collection of the 3 rim types of jap rounds but this one with full rim and no headstamp and the 3 primer crimps has me stumped ,hopefully some one will know the answer and put me out of my misery Randy


#4

Randy-- According to Ken Elks in his publication “Japanese Ammunition 1880-1945” a green primer annulus on 7.7mm Navy Rimmed indicates a Incendiary loading. He also states that all 7.7mm Navy Rimmed have headstamps from 1937 to 1943 and no headstamps from late 1943 to 1945. Further, all the loads utilize 3 slits on the neck to secure the bullet, EXCEPT Incendiary, which has a knurled cannelure at the case mouth. The only problem is the drawing he shows of the case head shows a ringed primer, not the 3 stakes you describe.


#5

Japanese cartridges (from personal observations and Elks "Japanese Ammunition "Handbook, note the followiong things about Primer crimps:
very early 6,5 ammo (Type 30, 1897) was uncrimped, but after the introduiction of the M1897 Hotchkiss MG in 6,5mm, they strated Three stab crimps of the primer. This continued in all 6,5 Ammo to 1945.
Largewr calibre ( 7,7 cal. ammo), ALL used a large ring crimp, similar to the original .303 British from which it was copied; as the IJN (Navy) was the first to adopt a 7,7mm cartridge (the 7,7x56R (aka .303 british) they also copied the primer size and the crimp. The later Army developemtns (the type 87 and 89 Aircraft MG cartridge (7,7x58 Semi-Rimmed< used a smaller diameter primer ( 5,5mm, the naval case used 6,35mm) and it too was "Ring crimped. In 1932, the army adopted the Type 92 for its new nambu ground gun, and it used the Type 87/89 case, but with a heavier load and bullet. Again, the primer was Ring crimped.
With the development of the Type 99 cartridge ( already in use in the Type 97 (aka Vz26 mechanism) Tank gun, the new, Rimless ZType 99 (Rifle and MG cartridge, also used a Ring crimp throughout.

But in 1937-8, the Airforce adopted some German MG17s (in 7,9mm) and so another cartridge, very similar to the 7,7x58 (both 92 and 99) was entered into service, the 7,9 Type 98…and to distinguish it from the very similar type 99, the Primers of the Type 98 were “Three stab crimped” as a simple distinguishing mark, readily visible.

I have samples of three stab 7,9 from an ammo dump in the Pacific(next to an airfield), and they werre sold as "7,7 cartridges (collectible)…a closer examination and measurements showed the true nature of the three staked cartridge.

As to headstamps, the Navy used HS up to 43, and then pressures of war caused abandonement of the HS on .303 cases (the Navy used Army isse, unheadstamped 6,5 and 7,7 types 92 and 99 for its marine Infantry)

The probable reason for a stab crimp on .303 is that it is not Japanese (maybe Chinese, in the immediate Post war period,) OR, very late war Japanese, when stab crimping tools were used as there was a lack of proper ring crimping machinery due to Bombing, etc…

Closer examination (even maybe dismantling) of the cartridge is necessary.

Regards, Doc AV
AV Ballistics.