.308 Mas

[roberts]

Mas in 308

I am playing with a Mas 57/49 in .308 and like a lot of others I am having problems with dwell. I have found that the So.African battle pack ammo will shoot 10 shots faultlessly. A real joy. I am guessing that it is loaded with a fast powder based on it's performance. So far anything else fails to extract , often with damage to case rims.

Am wondering what my options are relative to faster powder for the .308. Anyone seen any data for Lil Gum or Varget, H-110? Or is that entirely out of the box.

On the other hand maybe a stiffer spring is the answer, adjustable gas block? Suggestions? By the way this rifle has an amazing muzzle brake, 10 rounds South African ammo as fast as you can pump the trigger and all straight back, No muzzle climb.

[TacBlade]

Got any pics?

[Cabinetman]

I've owned all of the French semi-auto rifles including a couple of MAS 49/56 that CAI converted to 7.62 x 51.  Of course the French, themselves, were investigating that conversion and actually made some of their rifles in that caliber before they decided to abandon it.  CAI decided to mimic them and converted quite a few of the surplus they bought.  They also left a number of them in the original 7.5 French.  Obviously 7.62 x 51 is a lot easier to find and it has ballistics that are very close to the 7.5 original cartridge.

A number of the early conversions were done poorly and became "clubs" after a few rounds. Later efforts were more successful and it would appear that you have one.  A long while back there was a lot of discussion about adding a gas valve.  Frankly, if the rifle works then why make any alterations? 

Regarding your ammo for it, I would hesitate to use anything but surplus in that rifle.  That SA you've got is excellent stuff.  I shoot a lot of it myself.  The reasons are that the pressures and burn rates in the surplus are different than commercial ammo. Cases in surplus are heavier, too, and work well in the loose tolerance military chambers.  In addition, the primers are much harder in the surplus ammo.  Softer, commercial primers are subject to slam fires, espeically in the MAS family of rifles.  These rifles are beasts; military firearms and designed to run a certain way in all kinds of environments.  Unless you could find heavy brass cases, hard military-style primers and a ball powder that burned with the same pressures as surplus 7.62 x 51, I would be careful.  Commercial ammo has also been known to break extractors. 

Just my 2 cents.

Rome

Left to right MAS 36 MAS 44 MAS 49 MAS 49/56

[roberts]

I bought 3 of the rifles as on the rt. with the slip- on butt plate and short fore-end 10 or more years ago. Two are still in the boxes. The recent discovery that they, or at least one, will shoot SA ammo has obviously

changed the equation completely. I also think they are incredible rifles when they work. This Am I loaded some ammo using 150 grain boattail match FMJ ammo with 35.3 grains of IMR 3031, which was the fastest powder I had on hand that I had any data on. The load is supposed to be at about 2400 fps. per the Hornaday manual I got 10 /10 perfect function. The brass is R-P once fired.  I also have two of the military bolt rifles as you do on the lt. In addition I have a commercial sporting rifle in 7.5 x54. It is the same rifle pictured in Frank DeHaas' book on bolt action rifles. He was favorably impressed by the extreme simplicity and strength of the design of this bolt system.

I intend to continue with the SA ammo as long as it is available. I had not considered the relative strength of brass or hardness factor relative to military primers. I will be interested in the possibilities as one never knows when availability of certain materials will dry up. I am just interested in options. Would also be interested in acuracy potential.

I very much appreciate your response in this thread as there is so much to know. 'So many things to take into consideration.

[Cabinetman]

I still remember when the MAS 49/56 hit our shores.  They were sooooo inexpensive.  A lot of places were selling the on a "two-for" basis and they came with a heavy plastic package with night sights, cleaning kits, and other accessories.  Quite a bargain.  If you have two still in the box, you've got yourself quite a deal as their prices have double or even tripled over the years. 

The CAI conversions were pretty agressive and some times poorly done.  At the time they were introduced, the internet was ramping up and a lot of mis-information about these rifles was being posted up on bulletin boards and new forums.  I'd estimate that a healthy percentage of the 49/56 had issues...probably in the 5-8% range but no more than 10%.  Bad news travels fast.  The rest worked fine or just had rough chambers.  I loved them very much with the exception of the limited 10 round mags and the relatively rough rear sights.  They're similar to the M1 Garand with the peep but they just didn't have that sophistication of the Garand being a shorter rifle, too.  But I ran mine all the time and I fell in love with the NATO caliber.  It's a rugged, attractive ( I think so), reliable rifle and quite accurate. 

If you're going to build ammo for it, just be careful of the primers.  That bolt slams home with some authority and the firing pin could surprise you with a slam fire. They have been reported over the years although weren't that prevelant. Tear down an SA round and see if you can duplicate the powder with modern stuff.

Rome 

[roberts]

Below are the pics of the commercial mas.  Of note, it is an odd caliber 7 x 54.  Note the safety in the trigger guard.

mas2 by jenjscott, on Flickr

mas by jenjscott, on Flickr