KOISHIKAWA ARSENAL Siamese Type 46/66 Mauser

Seller Description For This Firearm

For sale is a very cool and historical Siamese (Thai) Type 46/66 Mauser rifle manufactured by Koishikawa Arsenal (Tokyo Arsenal) in Japan.

These were produced under contract for Thailand around 1903-1908 as the Type 46 (R.S. 121) with the classic Chakram (wheel) crest still intact on the receiver, along with the Koishikawa four cannonball arsenal stamp. It also shows the later Type 66 markings, which typically indicate an upgrade/rechambering to the improved spitzer loading in the 1920s.

Caliber note: It appears to be in the original/upgraded 8×52mmR Siamese (rimmed) caliber based on the markings and history of these rifles, but I have not had it chamber-cast or gauged. Please verify yourself or have a gunsmith confirm before attempting to shoot any ammo. Do not assume it will safely take standard 8mm Mauser (8x57) rounds.

Condition notes from my personal inspection: The bore looks bright and shiny with good, strong rifling (see muzzle photo). The bolt cycles smoothly and the action functions well mechanically on this strong Mauser 98-style design — it has the sliding dust cover typical of these Japanese-made versions. Metal finish is a honest gray patina with some light wear and scattered marks from honest service use, but no major pitting or abuse. Wood is solid original with nice grain, some normal dings, scratches, and character you’d expect on a 100+ year old military rifle. The buttstock has a nice crisp Thai inspection cartouche. All the right markings are present and clear. Overall a very presentable collector piece with a strong, smooth action that should make a good shooter once properly inspected and confirmed by a gunsmith.

Barrel measures right at 30 inches.

Serial and other details: Importer-marked 2700 on the receiver (original Thai serial is in Siamese numerals on the rear bridge). Strong Mauser controlled-feed action.

This is a neat, lesser-known variant with great Japanese build quality on a Mauser action. These don’t come around every day and make a fantastic addition to any milsurp or Asian military collection.

UPC	ECOM00586144
Action	BOLT ACTION
Barrel Length	30" BARREL
Caliber	8X52MMR SIAMESE
Capacity	5 ROUNDS