Siamese M98 in 50-110

[fsrmg1]

Is it possible to modify and build up a Siamese M98 in 50-110? They seem to work well when modified to 45-70 or 348 win, 50-110 might be a good step up.

 

[crs]

I have an old magazine article that says Siamese M98 can be chambered for 45-90, if that helps to answer your question.

 

[Hunter4752001]

I have a Siamese mauser which I originally bought with the idea of one day converting to 45-70. It still hasn't happened.

There are more than a few problems. The bolt face has to be opened up to accommodate the rim size. Not too big a hassle, but requires a good machinist. Frequently, the feed rails in the action may need to be tuned to allow the cartridge to feed but not so much as to cause misfeeds. Finding a smith experienced with the Siamese action may be an issue. Because of the way the magazine was designed, most Siamese mausers are missing one or all of the following: follower, original follower spring, floorplate. These are unavailable worldwide. The spring can be substituted with a Springfield or similar but I'm not convinced its a good match. A Japanese Type 38 floorplate can be modified to suit the Siamese Mauser, Hoosier gunworks have instructions. The follower is a big problem. A standard mauser follower is a poor match as are most of the recommendations commonly guessed at on the net.

Most of the minor parts are also no longer available. They are similar to standard mauser parts but just different enough to not fit. Likewise, some threads are standard mauser threads (Whitworth form) however others are obscure Japanese threads from a per-standardisation era, neither metric nor inch based.

Gun Parts Corp in the USA have some parts, but in 2018 they stopped international sales. I don't know if they have since resumed.

A good machinist can overcome all of these issues, but just be aware of what the project may involve.

 

[fsrmg1]

Thank you Hunter, I would only attempt this with a complete action, and preferably one that has already been correctly modified to 45-70 already.

Finding a good gunsmith is likely to be the biggest obstacle to overcome. Twenty years ago easy, but they all seemed to have vanished in the past 10 years as they are getting along into their 60s and 70s now...

I'm scared to let many of the remaining so called gunsmiths touch anything of mine, as they seem to stuff it up as often as not. The old apprentice trained system produced some really good smiths, now we only have a lot of parts changers...

 

[bruce moulds]

what cosiderations are necessary.
first is cartridge overall length. what is it and can it be made to fit.
another is thickness of barrel steel in the threaded section of the barrel.
the 50 cal will remove more metal here than a 45 cal.
if of marginal thickness, ammo might require low pressures.
then getting it to feed. remove too much metal in attempting to do so and the whole thing is finished..
is the bolt face and extractor large enough for the rim diameter.
just some thoughts.
bruce.

 

[Milehighshooter]

Why the 50-110? If its just a bolt action rimmed .50 you're after, a .50 Alaskan would probably be easier, if the S98 can be readily changed to a 348 (50A is based on the 348)

 

[fsrmg1]

I suppose the 50 Alaskan would be an option as well, but the 50-110 would offer a significant case capacity advantage, thus offering a huge ballistic advantage when loaded up to similar pressures.