Rebarrel a Mauser to 45-70?

[rodgervich]

Anyone done this conversion? Books indicate the 45-70 is fairly low pressure but big. I have nothing bigger that 30-06 and thought this would be a cool single shot rifle conversion. I've done bolt face/extractor work so I'm not worried about that part. Not interested in magazine mods, it's too much trouble for me, so I would just hand feed singles.
I have a 1950 Mexican Mauser with nice metal and matching numbers but the barrel bore is badly corroded. Rifling is strong but the entire bore is frosty with pitting and fouls up REAL quick, I use it for shooting rocks with the cheap surplus ammo. This is what I'm thinking of converting.
Don't know if it has any collector value, if so I'll just leave it alone.
What do you all think?

[John Traveler]

Sure it's possible, and even easy to convert a Mauser 98 action to .45-70.  However, it may not be terrifically practical.  I've done one, examined several, and found the following pitfalls:

1.  Small-ring Mausers (including your Mexican Mauser) use a smaller barrel shank in common with M93, M95, M96, most Turk and CZ Mauser actions,  That smaller barrel shank does not leave you with as much safety margin as a large-ring Mauser action.

2.  The standard .45-70 rim dimensions on the M98 bolt face leaves very little extractor purchase.  Thinning the case rims is one recourse, or using another, similar cartridge case is an improvement  A popular conversion a generation ago was the .458 x 2" American.  This gave belted magnum rim size, reliable extraction, magazine feed, and hot-loaded .45-70 ballistics.

3.  The standard .45-70 cartridge does not magazine feed without major modification of the receiver rails.  A "hand-fed" cartridge will not chamber properly with extractor pickup for the reasons stated above.  The large rim, minimum extractor grip, etc.

4.  Your good-condition Mexican Mauser probably has little collector's value with the ruined bore.  If you decide to re-barrel it to .45-70, you probably can't duplicate the military stepped barrel profile because of the large caliber.

5.  It's still an interesting project, but entails LOTS of fussing, feeding, and work.

HTH
John

[rodgervich]

JT- Wow! Thanks for your input, that's good stuff. I did some research on the .458 American and it looks pretty neat. I was hoping for the 45-70 because the "standardization factor", dies and components are cheap compared to a wildcat, on the other hand the "wow" factor is much higher with something nobody has ever seen. I just want to shoot big lead slugs at steel clanger targets and stuff I'm not planning on hunting with it, but as long as I have one...
I'll keep the .458 American in mind though. Doesn't seem to be any less sensitive to the small ring safety margin but with low pressure cast loads I would feel pretty confident with life and limb staying intact.
I appreciate your experience, I'll post the results of whatever I may do.

[John Traveler]

Glad to help make your decision.

Incidentally, the late, great P.O. Ackley (designer of the Ackley Improved wildcats) once barreled a .30-06 rifle and progressively turned the barrel diameter down and kept test firing it with military .30-06 ball ammunition.

He got the barrel down to 0.020" at the muzzle and 0.080" over the chamber.  That's EIGHTY-THOUSANDSTHS OF AN INCH chamber wall thickness!!!!!  And the barrel held up!!!  Just think of it:  a high power rifle chamber only twenty-five times as thick as a sheet of typing paper!!!

Now, that was certainly NOT a practical barrel, nor anything that a sane gunsmith would do for a customer, but you get the idea.  
Modern gun steel is ferociously strong, but it's certainly comforting for most of us to have extra steel between the chamber of a high power rifle and our faces when we touch one off.

John

[gunnut69]

I'd have to agree with John on most points but the Mauser is quite easy to single load.  Pressing in of the extractor between the extractor band and the tail will allow the claw to jump the rim with ease.  The ideal action for this conversion would be one of the Saimese actions.  Designed by Mauser Werke to function a large rimmed round they require little work to convert the 45-70..  But they've become scarce and a bit pricey.  I'd suggest converting a No.4 British Enfield.  You could just buy one as they are currently being converted to 45-70(by Century Arms I 'think') and sold on the commercial market but what fun is that.  Rebarreling is fairly straight forward and simply buying a spare mag from Century Arms would make the rifle a repeater.  Wouldn't try converting it into a rimmed 458 Winchester but with most sane 45-70 loads it would be amply strong.  If your really adventurous how about a 40-70 Sharps bottlenecked??  Actions are cheap and plentiful..  That little mauser would make a really nice donor for a lightweight mountain rifle.  If your ever inclined to sell it just PM!!

[Double D]

I have a Siamese Action and I might be talked out of it.  Drop me a PM.

[Mikey]

rogervich:  John is right on this one, that's for sure.  Also, the Mexican Mausers are known to have soft lugs or lug recesses and may not be the mauser model of choice for rebarrelling.

If you are looking for a 45-70 on a military action, I understand that Century Arms is producing 45-70s on British 303 actions, which are strong enough to handle the 45-70 caliber.  They are also smoother and quicker than most military mausers actions are.  If you definatley want to do this on a mauser, the Siamese Mauser will reduce the amount of work that must go into the project as the bolt face is already designed for a rimmed cartridge.  Beyond rebarrelling, you will need to deal with the magazine feeding issue, which is a problem for many bolt actions.  Hope this helps, and buenos luck.  Mikey.

[savageT]

Hey Guys,

Last time I checked, those Enfield .303 to 45-70 conversions were being done by Gibbs Rifle Company.  Take a look..........
http://www.gibbsrifle.com/

[Kywoodwrkr]

Interesting!
I think I saw an ad for the Enfield conversion rifles to 45-70 in the last Southern Ohio Guns paper they sent me.
Three shot magazine?
This is from memory which fails me quite often.
FWIW DaveP

[gunnut69]

I always get in trouble when I try thinking!!  Gibbs Rifle Company is of course the right answer.  They are still in production and do have spare mags available..  That last would sure make things easier, heck Maybe I even need one of those!!!