8x50 Siamese


How hard is it to find 8x50 Siamese Cartridges theses days. For collecting, not shooting.



I usually see at least two or three examples of 8x50R and 8x52R Siamese at most ammo shows. Price is usually in the ballpark of $2-5, and condition is sometimes pretty poor.


The 8x52s have survived much better than the 8x50s. You can still find the 8x50s which have not gone bad but most have.


Were the 8x52’s a replacement/upgrade to the 8x50 round?



Yes, the 8x52R (TYpe 66–1923) Cartridge was a Velocity and Performance upgrade–Spitzer, heavier charge, slightly larger case) on the original TYpe 45 ( 1902) Round nosed, cylindrical, slow cartridge…identical in performance to the Austro Hungarian 8x50R ( 1888-1893 designs).

The Upgrade was a result of Royal Siamese (Thai) Army observers on the Western Front in 1914-18, and the perceived efficiency of a spitzer bullet over round nosed ones. As well for Aircraft MG use.

The Japanese, the builders of the original T45 Mauser rifles in 8x50R, designed the new cartridge (Type 66) for use in a new built Arisaka Design Rifle, to be made at Tokyo Arsenal (Koisihikawa), and these were delivered 1925-29 (delay due to the great Earthquake of '23, which partially destroyed Koishikawa, and caused the setting up of Kokura arsenal and the production of rifles at Nagoya as well.)

SO the RTA Arsenal at Bungsoo converted their Vickers guns to 8x52R, and a slow process of converting the Mauser T45s to 8x52R as well… simply reaming out the old chamber ( case dimensions of the 8x52R were slightly bigger and longer than the 8x50R, by a small amount. This allowed for, worn or scored chambers to be “Cleaned up” ( 5-10 thou.). The rear sight ramp was also 'ground down" for the flatter shooting bullet, and as a result, T45/66 rifles have only partial graduations on the sides of the rear sights, whilst the original T45 ( 8x50R) rifles have a complete and more curved rear sight ramps.

Doc AV
AV Ballistics.
PS, the reason for the “8x50R Siamese”, was that in 1897, Siam bought a batch of M88/90 Steyr Mannlicher rifles from OEWG Steyr ( part of a defaulted Bulgarian delivery) and adopted the A-H 8x50R cartridge.

They were about to adopt a G98 type Mauser in 7x57, when it was decided to adopt a Mauser, alright, but in 8x50R…commonality of ammo with the earlier Mannlichers…and Japan got the Licence from Mauser to build them…as the Oberndorf Factory was fully engaged with the Turkish M1903 contract ( Receiver design also the basis for the Siamese rifle, with variations.).

Despite the disagreement of some cartridge “experts” that the 8x50R AH Mannlicher cartridge and the 8x50R T45 Siamese are “Different”… they are actually interchangeable, and the Siamese is derived from the Austrian cartridge.
BTW, a T45 cartridge will fire safely in a T66 chamber for 8x52R, but NOT vice-versa (the 8x52R will not fit or chamber into an 8x50R chamber.)

Doc AV
AV Ballistics.


Thank you Doc! Another question well answered.



A good summary by Doc of this often confused subject.

The only consistent difference between my specimens of the Austrian M.88 and Siamese Type 45 (M.1902) cartridges is that the Type 45’s shoulder is set slightly lower than the M.88’s (its neck being about 2mm longer), and its case diameter just below the shoulder is 0.5mm less (11.5mm compared with 12mm).

Although the two rounds are technically “different” (both had distinct DWM case numbers), the Type 45 Siamese cartridge would clearly operate satisfactorily in the M.88 Mannlicher rifle, and the Japanese-made Type 45 rifle may have had sufficient chamber clearance to safely load the M.88 Mannlicher round. However it might now be difficult to prove this for certain, as Type 45 rifles in the original 8x50R calibre are very scarce because, as Doc says, the majority were later converted by the Siamese to use the improved Type 66 (1923) 8x52R cartridge.

John E


My lone Type 45