Siamese Mauser Action/ 500 Alaskan.....input appreciated

[beechbum444]

Evening, just won a Siamese Mauser action on GB...the plan is a 500 Alaskan.....I have no need for this thumper, but there is something about that round that draws me to it like a mosquito to a bug zapper.....Someone on here has got to have either done this before or thought seriously about it or may have spare parts lying around.....any input appreciated ........regards

[smithnframe]

The norm is to convert these to 45/70. I have one I re-barreled to 348 Winchester! I have another I’m planning on doing up in 45/70. Good luck! I’m not familiar with the 500 Alaskan?

[Texas by God]

The .50 Alaskan is a .348 case necked up to .50 caliber. There will be action rail and bolt head/ extractor modifications required for the larger case head, I would imagine. I don't know about a .500 Alaskan.

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[Rapier]

The last S. Mauser action I bought was from a guy that planned on building the Alaskan out of it. The action is the last variation of the 98, not the first, built by Arasaka of Japan prior to WWII for the now Thai government, under contract.

The 50 or 500 Alaskan is based on the rimmed 348 Winchester case necked up to 50 cal., The reloading data is quite old and one of the old methods of making bullets was to reverse a 50 BMB bullet that had been cut off in a lathe to form a 400 to 500g bullet, using the BT base as the nose. Now with the likes of the 500 S&W, 500 ***, etc., there are more bullets available. The powders used for the 45-70 would be quite acceptable, plus the 50 cal bullet moulds. You could use a load program, like Quick Load to give you pretty good indications of starting loads, then work up from there. It is not a huge conversion project as some might think. I have a couple of 45-70s I built on the action and the 348 is not all that different, but the bullet selection is narrow and barrels are at the top of ATF rules, so not that many made or available, as discount or sale items, for sure.

There was an old article in Guns and Ammo or Shooting Times, as I recall, about a build and reloading for the rifle. Must be 40 years ago.

It is a thumper of the first order for a fact and most I have read about were built specifically for Brown Bears, and for use at close range by guides. Penetration figures were in the vicinity of “you must be kidding.”

[beechbum444]

As far as the 500 s and w boolits go....someone tweaked this round a little and I think its called the 500 B and M, basically bringing the diameter down to where you can use the 500 smith and wesson boolits.....i think this is the route im going. at first glance, this round looks like a long 500 s&W...only with less pressure....hopefully theres a muzzle break somewhere that can tame this beast

[John Taylor]

Bullets designed for the 50 BMG have the core slightly off center, so you get the "cone of fire" out of a machine gun. Found this out about 40 years back when I was helping build 50 BMG single shot target rifles. Barns was the only one making 50 cal. bullets at the time and they were round nose. We ended up make bullets out of solid brass with an automatic screw machine. We were getting 3,400 FPS with a 615 grain brass bullet out of a 45" barrel. I'm sure the sniper rounds used today were not for the machine gun.
The 500 Alaskan, 50 EX and 45-70 have the same rim size. The S&W uses a .500 bullet and the 50 Alaskan uses a .510. The 50-70 usually uses a .512. I have chamber reamers for all four plus the 500 NE.

[GOPHER SLAYER]

I owned a Siamese Mauser that was converted to 45/70 and it was very well done. It had a Lyman 48 rear sight. It was tolerable with reloads but with Winchester 250 grain soft point rounds it was mean. I had one box of twenty and I wanted to shoot all the rounds to get the brass. I tried to pull the bullets with the Foster Collet puller. Never could get that thing to work. I asked friends and all to shoot the gun . Only got three takers. I pulled the bullets with Lineman's pliers. I sold the rifle to a man on this sight. I would not pull the trigger on such a rifle chambered for the 500 Alaskan for any price.

[beechbum444]

if it gets built...guess ill just save it for when my nieces start bringing boys around that want to shoot cans in the back yard.......

[skeettx]

One of my 45-70s is built on a P-14 action
The 348 case would just be too big for the bolt, in my opinion
Mike

[rockrat]

Isn't there a 50 AK that has a 45-70 rim and case length. Body is just a bit larger to handle the .510 boolits