Rechambered 1912 Chilean Mauser

[Sky Dog]

20 or so years ago I bought a 1912 Chilean Mauser chambered in a .308.
I've done all the research on it's origin and rebarreling. I'm having some
cycling problems though. It was a 7mm in a previous life. I know the 7mm
case diameter smaller than a .308, but I'm not sure if that's the issue. The
Styer action is like glass, so I want to do it justice. Thinking about rechambering it.
When I ask my late father what to do, he said buy a Model 70 and forget about it.
Any thoughts?

 

[Edarnold]

I've got one of those sitting in the closet, bought during about the same time period. The conversion to 7.62 NATO was done by setting the original 7x57 barrel back and Reboring it to .30 caliber. Pretty crude job, just enough care to be workable. The one good thing in my rifle was installing a filler block in the front of the magazine, also shortening the follower, to fit the shorter NATO cartridge. This did improve the reliability of feeding, if your rifle lacks this change it may explain your feeding problems. It's a standard 98 Mauser action, there are plenty of new barrels from sources like ER Shaw or Midway that will give you your choice of calibers. As far as the barrel on the rifle now, I wouldn't waste any effort trying to improve it, it's the proverbial lipstick on a pig.

 

[HankC]

7mm case diameter smaller than a .308

Same case base diameter as 308.

The conversion to 7.62 NATO was done by setting the original 7x57 barrel back and Reboring it to .30 caliber.

That maybe incorrect. Most of the 1912 Chilean in 7.62NATO were converted by using US 1903 barrels (2 grooves), rechambered to 7.62NATO. There are also 4 grooves 1912s in 7.62 out there, don't know if they are the rebored 7mms. Many small ring (1895?) Chilian 7.62NATO out there too, those are rebored with chamber inserts which may not be safe. 1912s are large ring mausers.

a filler block in the front of the magazine,

My 1912s do not have filler blocks and feed well. I had 2 at one time. On the other hand, my 93 small ring 7.62 mausers have the blocks at the front.

Describe the cycling problems, maybe simple fix.

 

[Vern Humphrey]

I know the 7mm case diameter smaller than a .308,

They have the same head diameter (.473) but the .308 is wider at the shoulder.

Your problem, however, may be that the .308 is shorter (by 1/4 inches.) Try loading your rifle so the cartridges are farther forward in the magazine, and see if that helps. If it does, have a gunsmith shorten the follower and put in a spacer.

 

[Jim Watson]

The difference between 7mm Mauser and .308 Win (other than bullet/bore diameter) is not in the head, but in the shoulder. The Mauser round is longer and more tapered and the shoulder is smaller but farther forward. That can affect feeding, as you see.
I know there are many 7mm or 8mm conversions to .308 that work well, but not all.
A GOOD gunsmith could grind on the frame rails to get .308s to feed.

I would be more likely to have it rebarrelled (Shaw is about the most economical.) back to 7mm or maybe .257 Roberts or 6mm Remington, which are close in cartridge body shape to 7mm.

 

[Sky Dog]

Think I'll buy a Win Model 70 and forget about it....LOL

 

[Edarnold]

Actually, the filler block on my 1912 is at the front of the magazine well, shaped to extend the feed ramp farther down. So the cartridges are held at the back of the magazine, where there is the least difference in dimensions between the 7mm and the NATO round. As soon as the bolt starts to feed they encounter the feed ramp and cam up, which does seem to solve the feeding problems. As to the identity of the conversion barrels, what's on my rifle has two groove rifling, but has the stepped contour typical of a Mauser military. So depending on what was available the Chilean arsenal apparently used several methods. Nice action, but it's no Model 70.

 

[tahoe2]

Sky Dog

Midway has a few Green Mountain Series 3 barrels (formerly Adams & Bennett) under $100 bucks; these are not drop in's and need to be finished reamed once installed, since your 1912 is a standard 98 action, it will handle full length standard rounds such as 270 win, 30-06, 35 Whelen etc... which also have the same size case head (.473") as the original 7mm mauser/ 7.62 Nato. Other options are out there as well, Numrich, Libertytreecollectors, etc... just depends on how much you're willing to spend (this could end up being quite costly). If you find the conversion is not cost effective and would like to off the 1912, I might be interested in the 1912 action depending on condition, thanks and Good Luck !!