Ok guys you've got me squared away on box dimensions... so help again.

I am trying to figure out whether or not I want to make a 45-70 on a Siamese Mauder, or a P14 Enfield. Iam also thinking that a 450 Marlin on an old M98 would be just as good.

I always think of the 450 Marlin as a long-belted 458x2.1 without the case trimming and neck reaming. It is what the 458x2 should have been.

I do my own work, so this is just a project gun to play with. I do not have the reamer yet. I think that Charlie Sisk was offering 450 Marlins on bolt action Model 70's, and Ruger 77 in adds in the "Rifle" magazine.

The idea is to make a short compact rifle with a 20 or 22 inch barrel. No matter what i do I'll throat out to use the extra magazine space to allow a max OAL of about 2.8 inches. I'd like to shoot nothing less than 400 grain cast bullets.

Give me your thoughts on my project. What have I not thought of?

There is no reason for the .450 Marlin.
The .458X2 is not that difficult to make.

BTW what is wrong with a good strong single shot?
The 45-70 is not a particularly good choice for a bolt gun if you do not like the 458X2.

Build a .458 win mag on the P-14 or on a 1917 using a P-14 bolt. Everything about the project will be easier, and the bullet won't know which case it started from.

dave

I have three Siamese Mausers in 45-70, a pre 64 Win Mod 70 Custom in 450M and a Ruger M77 in 450M.

I love all of them. I didn't build them (don't know who built them) bought them already converted. I have two of the Mausers in the smith's shop having the stocks refinished, a front cross-bolts added, receivers bedded, the barrels free floated and Gentry 3-position safetys installed.

Just tossing out a few things to think about and consider.

1. The 45-70 cases capacity average about 8% bigger than the 450M. The smaller capacity of the 450M is due to the webbing/belt. I can push them nearly as hard as the 45-70s but the pressures can peak a bit faster. I can still very safely push 350gr TSX's to 2400fps with no signs of pressure issues.

2. Parts for the Siamese Mausers are a bit difficult to find and getting harder everyday.

3. If you use the 450M in the Mausers you won't have to open up the bolt faces nearly as much if at all compared to the 45-70's.

4. It is claimed the metallurgy of the Japanese at the turn of the 19th century exceeded that of the Europeans and the Siamese Mausers actions are legendary in there strength.

5. The belted 450M cases seem to feed better in both bolt actions and the Marlin levers than the 45-70 rimmed cases. Since it is the same way with both style of actions it leave to believe it the rim and not just the actions.

6. One of the Mausers is able to hold "four down" 45-70s and the other two can only take "three down". The Win and the Ruger also only take "three down".

I love them all and each has positives and....less positives (LOL)

Good luck!

Stay the heck AWAY from the 45-70...the big rim causes feeding problems even after you get it to feed.

I have two 458 Americans, a Marlin switchbarrel levergun and a SMLE 2A I built and a BLR 450 Marlin I bought...

It was so much easier to get the 458 belted mag case to feed in both the tube and box mag and NOT hang up at the wrong time than that HUGE 45-70 rim.

I used a 458 WM reamer so I could pick the case length that fit the application to get the max COAL and case volume with whatever bullet I wanted to use...AND get a bit of "freethroat" at the same time...I use Lee and Lyman reloading dies. The Marlin COAL is limited to 2.62", but the SMLE will go to 3.03"...and a mauser will get ~3.26-.29" with a full length 458 WM case.

I did a VZ-24 in 9.3x62 and the SMLE for the experience and quickly learned there are easier and cheaper ways to get there in todays world.

The Siamese and P14 you mentioned are old, as m3taco stated, and the mauser offerings are limited and the good ones are costly. You can pickup a modern receiver for chumpchange compared to what you will spend for a custom mauser...but it's your toy and your choice.

There are also better cases such as the WSM/RUM/RUGER that can be turned into excellent 45 and 50 cal's which will give you better ballistics.

There are just a WHOLE lot of variables you need consider before you decide...and there are many answers to your question already on this and other forums...so start your searching....I spent several months researching online before I decided which way to jump with the Mauser. I still harbor thoughts of adding another barrel or two for it as Lothar Walther has many "screw-in" prefits available clear up to the Jeffery.

It was also a bit easier for me as I did all the work and made my own tools so I didn't have to pay the piper, and only bought the grinding cup to do the mauser bridge...Brownells had one cheaper than my there tooling catalogs.

You might also keep watch on the auction sites as conversions are always emerging.

Luck

I build my 450mar on a Savage Lh long action. The reamer was cut to min spec and throated fr cast boolits. Will shoot in3" or less with good cast at 200yds Clint

I would just go with the .458 Winchester in whatever bolt action rifle I preferred, and load it to whatever level I liked for the occasion(s) at hand...whether reduced a lot, only slightly, or full "balls to the wall".

I did have a Siamese Mauser in .45-70 by Sterling Davenport, and it never gave me any kind of feeding problem, ever.

I am in the process of building a 458 Lott on a P14 action.
The receiver must have been cast from ball bearings because it is harder than woodpecker lips to shape. Carbide bits did the trick.
I chose the 458 Lott because I can fire 458 Win mag in the same chamber. I got a 3# coffee can full of 500gr 458 bullets, so I decided to build something to shoot them in.

One other thing to think about - if all the above is not enough already.

If you have thoughts of, or any possibility of, traveling with it via either domestic or international airlines, you may want to consider the availability of factory ammo verses a wildcat or custom cases. If your ammo gets separated/lost en-route it might be very difficult to find some over the counter factory replacements to shoot and could REALLY ruin a trip.

If you look in the "Sporterized Military" forum, I posted a link to a guy who has rechambered a Moisin Nagant to 450 Marlin and seems to be happy with it. (I have no affiliation to the author, just found the article on the web and linked it). I do know that if I had a P14 action I'd be chambering it for a real cartridge, no offense intended to the 450 marlin.