Japanese 13.2 Hotchkiss rounds


#1

Japanese 13.2mm Hotchkiss ball rounds in my collection.

Steve


#2

Nice ones, Steve.

Some further information for those new to this subject: the Japanese actually referred to the 13.2mm Hotchkiss round as being of 13mm calibre. It was used in two guns, both naval: the 13mm Type 93 (Hotchkiss AA gun) and the 13mm Type 3 (Browning aircraft gun). Just to confuse matters further, there was also a 13mm Type 2 aircraft gun which was the German MG 131 (13x64B) in a percussion-primed version.


#3

The 13,2 Hotchkiss Japanese Ammo, along with the guns, were initially acquired from France in the early 1930s. And supplies continued after 1940 fall of France, both of ammo and Gun parts (magazines, especially).
In fact a lot of the ammo had to be “Remediated” in Japan, as it had function defects. Hotchkiss-marked magazines are still being found in the Pacific Islands, with Japanese-made Guns.
Italy also supplied Japan with 13,2 Ammo, both Italian-made and also “captured” French made ammo. ( also after June 1940).

Anybody find any Italian or French-made Hotchkiss ammo in a Japanese context ?(ie, pick-up in a Pacific Island, or in mixed belts from Relic Japanese Aircraft? ( I have BPD 12,7 from a Japanese Plane, with Japanese made 12,7 mixed in)…Pacific Island scrap metal source.)

PS, the same 13,2 Browning gun was used by the Airforce/ Navy in 12,7mm
(Type 1)…just as FN offered the M1921 Browning in 12,7 ( Vickews design) .50 BMG, and 13,2mm all for Aircraft use.
Strange that no one in Europe or Asia adopted .50 BMG, and rather took the lower power 12,7 or 13,2 cartridges, Probably because the BMG energy and ROF would have shaken a 1930s-era Plane to pieces…

Regards,
Doc AV
AV Ballistics.


#4

[quote=“DocAV”]PS, the same 13,2 Browning gun was used by the Airforce/ Navy in 12,7mm
(Type 1)…just as FN offered the M1921 Browning in 12,7 ( Vickews design) .50 BMG, and 13,2mm all for Aircraft use.
Strange that no one in Europe or Asia adopted .50 BMG, and rather took the lower power 12,7 or 13,2 cartridges, Probably because the BMG energy and ROF would have shaken a 1930s-era Plane to pieces…[/quote]

A few observations:

The Japanese Army Air Force’s 12.7mm Browning (Type 1 or Ho-103) was actually chambered for the 12.7x80SR Vickers export round, and the gun was smaller, lighter and faster-firing than the .50 BMG M2.

As far as I know, FN never offered a gun in 12.7x80SR Vickers; their 12.7mm gun was chambered in .50 BMG (12.7x99).

Before WW2, the .50 BMG was pretty well US-only. The 13.2x99 Hotchkiss round (which was the same cartridge as the .50 BMG except for the fractionally larger calibre, and was equally powerful) sold very widely in the original Hotchkiss AA gun, as well as being adopted by the Italians for the Breda M31 AFV gun and offered by FN in the Browning. AFAIK, only Sweden and Romania actually used the 13.2mm FN-Browning aircraft gun; the British and the French were interested in it (the FN version was lighter and faster-firing than the US M2), but Belgium was overrun before they could arrange to adopt it.

The .5"/12.7mm Vickers ammo had an interesting history. There’s an article about it here: quarry.nildram.co.uk/Vickers.html


#5

Was ammunition for this gun manufactured in Japan? I have never heard of them using that calibre before, it would be an interesting round to find.

I remember someone saying a while ago on this forum that a Japanese quartermaster must have been tempted to start the day by committing seppuku with the problems that must have arisen from four different calibres of rifle ammo. I didn’t realise there were also 3 different similar kinds of HMG ammo to cause yet more confusion.


#6

Falcon, yes Japan made 13x64B. I believe it is amongst the scarcest cartridges today.


#7

Its rare because the US troops successsfully destroy everything they get hands on. These later war ammo was used in the Peggy and carrier based bombers. Most of these planes where drawn back to fought in the motherland at a planned invasion. After surrender tons of these ammo was burried, dumped or blown off.


#8

What is the headstamp on that round?

I would have thought a few more of those rounds would be around that had been brought back as souvenirs, as they are small enough to fit in a soldier’s pocket.


#9

That looks just like the German version 13x64

Steve


#10

I believe that the Smithsonian Institution’s Aichi Seiran floatplane has a type 2 in the rear seat. The Japanese naval air force also used the 13 m/m Hotchkiss round in its version of the .50 M2 Browning, but that gun was altogether too bulky to work as a flexible gun in a narrow cockpit. JG


#11

It was, except for the primer. The IJN ammo had a conventional plain percussion primer instead of the German ringed electric one.


#12
  • Tony Williams posted above that Romania had also used the 13.2mm round which it is very true. => During WW2 the 13.2X99 Hotchkiss Long rimless cartridge [0.52-inch] was used by the Romanian anti-aircraft 13.2mm Hotchkiss heavy machine-guns. Romanian-built fighter aircraft (IAR-80B, IAR-81A and some IAR-81 models) from WW2, were armed with Browning FN 13.2mm heavy machine-guns firing the 13.2X99 round. => Romanian made 13.2X99 AP rounds with brass shell cases manufactured before 1940 have these headstamp markings: “13.2H” [at 12 o’clock position]; the four-digit date of manufacture [at 6 o’clock]; the maker’s mark “PA” for “Pirotechnia Armatei” [at 9 and 3 o’clock]. The Romanian made 13.2X99 AP rounds manufactured in 1940 and after that have similar headstamps with the exception of the mark stamped at 12 o’clock which was "13.2-“D” [not “13.2H” like before 1940]. The “D” mark shows that the Romanian 13.2X99 rimless shell cases were made from recycled brass [in 1940 and after that]. Liviu 03/14/09

#13

Hi Steve (and others),

I didn’t see this explicitely being asked, but in case anyone is interested in how to read the headstamps on these 13.2mm rounds, it is as follows:

Firstly the easiest part: the “13” simply reflects the calibre (which the Japanese “handily” state as 13mm, rather than as 13.2mm).

Secondly, the inverted ‘E’, reads as “yo”, indicating the “Yokosuka” Navy arsenal.

Finally, the date: as opposed to many contemporary headstamps, the dates are not given in Showa year notation, but rather in short Koki (empire) year notation. Hence, their base year is not set at 1925, but at 1940. Koki 0 (or more correct in full Koki notation “2600”) then becomes 1940, and Koki 2 becomes 1942. This is the part indicated in Arabic numerals before the dash. The second part (i.e. after the dash) is written in Roman numerals, and always seems to be either ‘I’, ‘II’ or ‘III’. It is believed that this notation was used to (respectively) indicate the following month intervals: “January - April”, “May - August”, “September - December”. It should also be noted that this type of ammunition has not been seen with post-1943 headstamps. It appears that all rounds manufactured in the later years of the war were headstampless.

Source: Ken Elks’ excellent new part 1 on Japanese Ammunition.

Cheers!
Olafo