Nagoya type 45 Siamese Mauser 1903

[billy67]

Hi,
I just acquired this nice Japanese Type 45 Mauser Siamese contract and I am not sure what is the appropriate ammo fit to it ? I read this rifle was originally chambered in 8x50r and later re chambered in 8x52r. How I can know ? The guy who sold the rifle to never fired it and told me its a 8mm.
Any inputs is welcome. Thanks

Information

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[seabot2]

A friend of mine recently showed me a cartridge he formed out of a Mosin Nagant shell for the 8mm Siamese rifle he has. I am not sure if he had an 8x50 or 8x52. He said the reloading dies are available but it would take a couple of form and trim steps to finish a shell. I could post a photo of the cartridge later.

[Patrick Chadwick]

The Japanese-made Type 66 was a short rifle. You have a Type 45 long rifle. A Siamese 1903 Mauser. The cartridge is the 8x50R Siamese. The Russian 7.54R Mosin-Nagant case would indeed be a good starting point for reforming.

The basic steps would be
First test case:
1) Reduce rim diameter
2) Trim to length (the first case will be experimental, as the neck expansion and forming will slightly alter the length
3) Anneal from about 1/4" below shoulder to neck.
4) Form in Siamese die.
5) Expand neck
6) Form again.
7) Check overall length of the test case, trim again if required, and for the succeeding cases adjust step 2) accordingly.

When you have got the dies and trim length adjusted, it should be possible to make further cases with fire-forming after Step 4) if you so wish. Personally, I prefer to get the cases close enough to avoid fire-forming, as this means a wasteful trip to the range just for that purpose - the first load in an old rifle is anyway in effect a fine-tuning by fire-forming, as many die sets seem to produce noticeably undersized cases.

As you can see, it is indeed a bit involved, and if you have never reformed cases before, I strongly advise you to get the help of an experienced reloader who can help you with the right degree of annealing, die adjustment etc.

[Bill Hollinger]

Because most of the 7.62X54R cartridges out there are steel would they make a good candidate for reforming?

[DocAV]

The Rifle shown in the Photos is a T45/66 Siamese Mauser (Originally 8x50R Siam, rechambered for the slightly larger 8x52R Siam in 1923 ( Year 2466), at the same time that the T66 Arisaka was adopted in 8x52R Siam.
BTW, all Siamese Mausers and T66 Arisakas were made by Koishikawa Arsenal, Outer Tokyo ( 4-Cannonball Logo) the T45s in 1902-1908, and the T66 in 1923-1926 ( See Frank C Allen, Siamese Mauser Rifles)..can be reached on GunBoards.com ( and NOT Nagoya).)

The T45/66 upgrade was done partly in Japan and mostly in Bungsoo Arsenal, outside Bangkok.

To differentiate the T45 (or 46) from the T45/66 Upgrade, look at the rear sight ramps...if the Siamese script is intact, and the "Hump" is rather high and curved, it is an original rifle made 1902-1908 or so; if it has the rear sight ramps "cut down," such that the Script numbers seem "cut off halfway", then you have a T45/66 Rechamber.

T45 in 8x50R are uncommon, even Rare...T45/66 are very common, for Siamese Mausers. On T45/66 the stocks may be original Japanese ( Two-piece Butt, like an Arisaka) or one-piece Siamese Replacement (Teak).

Cartridge cases:
T45 8x50R...use either 8x56R Steyr (Prvi) cases, or 7,62x54R cases, re-form in 8x50R Austrian Mannlicher die, trim and use long flat base cylindrical Bullets ( about .324" diameter).

If making T66 8x52R, one can use (undersized) the 8x56R cases again, with 8x52R dies (RCBS, CH4D) with some Head Bulging... or go the Proper way, using a .45/70 case for starters to give correct head size, BUT...either a Forming set (RCBS) is needed, or a step down series as follows :

1. Expand /size neck of .45/70 with .45/70 neck expander rod ( making sure the necks are not folded or bent, as is common in Bulk Brass like .45/70)

2. Form first neck with either 40/82 WCF, .43 Mauser, or 10,4x47R Vetterli dies, set to give correct shoulder position vis a vis chamber cast of chamber or original or fired case of 8x52R Chamber.

3. Neck with 9,5x60R Turk die, or a butchered .375 mag. die

4. Neck with .348WCF or .33 WCF die, Or Go straight to a 8mm Kropatschek or even the correct 8x52R die....Lubing at every step.

Small fold defects in early necking operations can be trimmed away ( bring case to 52mm Length...) otherwise, only trim cases when finish sized to 8x52R....

5. Turn rim from .605 (.45/70) down to .565", Thin rim slightly, and bevel back edge similar to 8x56R case. ( for ease of extractor engagement, otherwise a broken extractor may ensue.)

6. Anneal neck and shoulder.

7. Load with .324 Flat based Sptizer Bullet, or .324-329 Cast lead bullet.

Note: Siamese Mauser Rifling follows Austrian practice....315 BORE, .329-330 Groove dia. Use of a long cylindrical bullet required a .324 Bullet, so that the Base upset to obturate, but the rifling did not create excessive Friction, by not cutting deeply into the Jacket. With the 8x52R Bullet, it was a 170 grain Spitzer, but still .324 and Flat Based. ( less surface area contact, but still a flat base to obturate.)

Load: Start with Powder charge equivalent to 170 grain -.308 load ( Given the bigger volume of the T66 case c/f .308, the Pressure will be lower.)..then work up to accurate Load. The Mauser action ( Small ring, Small thread Barrel ( .980",) three lug with Arisaka Front Lugs shape, gives a strong action, and will take higher pressures in the 8x52R with ease.

Clips: the original 5 round stripper clips of the T45 and T66 cartridges are an Oversized Mauser type pressed metal and sprung clip...rare as hen's teeth outside of advanced Cartridge Collections....You will have to load individual rounds into Magazine...I have tried cutting down a Mosin Nagant clip ( same rim diameter, ) and spreading a bit the sides remaining to hold the .505" Body ( MN 7.62x54R is .485 head). Not very reliable.

IN Australia ( and for NZ) we make 8x52R cases from Winchester or Remington .45/70 Brass ( NO Cannelure in case)...info@avballistics.com.au

Doc AV
Down Under.

[Merle]

A friend of mine recently showed me a cartridge he formed out of a Mosin Nagant shell for the 8mm Siamese rifle he has. I am not sure if he had an 8x50 or 8x52. He said the reloading dies are available but it would take a couple of form and trim steps to finish a shell. I could post a photo of the cartridge later.

If it was formed from a M-N then it should be an 8x50R. You start with 45-70 for an 8x52R. The only way to be absolutely sure is do a chamber cast.

---------- Post added at 05:03 PM ---------- Previous post was at 04:55 PM ----------

Because most of the 7.62X54R cartridges out there are steel would they make a good candidate for reforming?

I used Sellior & Belloit to form 8x50R Steyer, which is very similar. Just avoid the surplus & the cheap Russian imports.