Siamese mauser 30/378

[ctylerclifford]

Hi,
First time posting.
Just received a siamese mauser action and was wondering if anyone would know what the maximum oal round it could handle.
I have in mind 30/378 since I'm going to have to have a barrel made.
I'm not interested in 45/70. I want a modern type round. I'm also having problems matching up parts made for mausers. No one lists the siamese as it is different in small ways. Any input would be appreciated.

 

[Kp321]

IMHO, that is an ill advised project and a waste of a good action for other purposes. The Siamese action is too short for 30-378 and the metallurgy is questionable. Plenty good for hot 45-70 loads but not for 70,000 psi Weatherby.
The Siamese action is well suited to 45-70, 348 based wildcats and other rimmed rounds.
Now, if you meant 30-348, that is another story that could work.

 

[ctylerclifford]

I meant 30/378 Sammi max pressure 63,816. I was shooting for. That caliber because from what I understand, they made 30-06 barrels for these, but I could be wrong. And saami max is 60,000 for 30-06.
I don't plan on maxing out the rounds mostly because it supposedly eats barrels fast in 30/378 if you do go to the hot end of the scale.
The 45/70 has a very low max pressure of 28000. Don't know why.

 

[ctylerclifford]

This is the chart I'm going by.http://http://www.lasc.us/SAAMIMaxPressure.htm

 

[Jim Watson]

The Siamese Mauser was designed for 8x50R, most rechambered for 8x52R, OAL 2.97"

The .30-378 Weatherby has OAL 3.648", no way will it fit the magazine and maybe not even the bolt stroke.

I never heard of a .30-06 barrel for the Siamese, the bolt face is wrong, the magazine is wrong. Why bother with all the work that would be required when you could cut up a German Mauser a lot easier?

8x50R is about like .30-40 Krag, a 40,000 psi cartridge. No doubt some of the conversions are loaded hotter, but the Mauser has more safety margin than the Krag. Not enough for 55% more pressure on a larger diameter case head, probably double the bolt thrust.

.45-70 is limited to 28,000 psi because of the many old guns and old design guns chambered for it. Even that is too much for the original Springfield.

I wouldn't do it.

 

[Edarnold]

Let's see: AFAIK, there are no inlet tend stocks for the Siamese action, so you will have to make one, or have it made from scratch. A lot of work or a lot of money. The action is no-where near long enough to accept the 30-378 round in the magazine, no matter how you modify it. It's very doubtful that the action is strong enough to withstand the thrust of full loads in this caliber very long until the locking lugs fail or the seats in the receiver set back. If you intend using reduced loads, why the Heck do you need to build a gun in this monster cartridge?
If you can find a gunsmith foolish/unethical enough to put such an abomination together, I wouldn't trust their work. If you actually complete this project, and decide it's not what you want, the resale value is going to be pretty much zero.
If you really, really have to have a 30-378, go on Gunbroker and buy one of the Weatherby Mark V rifles in that caliber: I found several new and used. Otherwise, take the cash you plan on spending on your Siamese project, make a neat pile outdoors away from dry foliage, spray well with lighter fluid, and burn it. Then find a buyer online for the Siamese action, a decent one is worth a couple hundred dollar, and sell it before you get any other ideas.
Sorry if this seems harsh, but this such a bad idea in so many ways that it needs to be taken out back and put down humanely before it can hurt somebody.

 

[ctylerclifford]

Oal was a real concern of mine. Something I was fishing for as far as the max overall actual number.
Siamese are large ring(1.410"). But the bolt is for rimmed cases. The distance between the receiver mounting bolts is a pain but not a limiting factor, except with regard to stocks. Action is 8.5" long.
I've heard of 7.62x54r and 348 winchester. http://http://www.thehighroad.org/archive/index.php/t-668030.html
348 win has a max case pressure of 40000 cup. Max pressure on the mosin round is 52000 psi. It seems the limiting factors would be 52000 max pressure and nothing over 3" long, but that isn't proven yet. Just that the round can be 3" long.
In an Unbarreled action 264 win mag brass and mosin rounds fit the magazine and cycle/ operate normally loading and ejecting.30-06 does as well. I don't have any other large rounds handy. 30-06 is roughly 3.5" long. This one is 3.317" and just a little bit longer than the round can be, as it won't stack properly n the magazine.

 

[ctylerclifford]

30/348 - when it's done I'll post pics. Thanks for the guidance.

 

[a98doc]

you could look at

450 Alaska a 348 Win based wild cat
Or I think a 50 Alaska will work but on that I'm sure I would need a case to test the fit.
I have two actions and I think a 45 70 is what I will do.
Unless the 450 Alaska will fit.
If I can help please ask

 

[ctylerclifford]

Thanks a98doc.
Isn't 450 Alaska close to 458 win mag in terms of performance? From what I've read about it, it's sort of like a 458/348AI, right?
I must say that the 7.62x54r fits snug in the stock bolt face. The 348 case has a rim diameter of 15.? I'm thinking the rim would have to be trimmed down to about 14.30 or there abouts.