Converting a MAS 49/56 to 7.62x54r?

[essayons21]

I was wondering if it would be possible and practical to convert a French MAS 49/56 in 7.5x54 French to 7.62x54r. I am interested in picking one of these up as a C&R rifle and converting it to 7.62x54r to be a fun rifle to blast away at the range on the cheap.

The rifles themselves seem to be of a robust and reliable design, and parts and magazines seem to be pretty cheap. I also think the 7.5 magazines would accept the 7.62 round without modification.

Someone will probably tell me just to get a SVT40, but I've noticed these are much more expensive, and magazines and parts are rare and very expensive.

Opinions are appreciated.

 

[Cosmoline]

Wow, those are radically different cartridges. I would think the 7.5x54 chamber would be much easier to convert to 7.5x55 Swiss, though I'm not totally sure if the case heads are the same. The 54R is different in every possible way.

 

[MMCSRET]

Why would you want to do this conversion? The 7.5X54 is the ballistic equivalent of the 7.62X54R. the French cartridge is actually easier to load for than the Russian, with a far greater bullet selection.

 

[essayons21]

7.5x54 is a bit hard to find and pricey. 7.62x54r is one of the cheapest centerfire cartridges available.

Cosmoline-

I'm not an expert on either cartridge. To my eyes they are pretty similar in dimensions, the main difference is the russian is rimmed and the french is not. Could you explain the differences?

 

[chestnut ridge]

I don't mean to be rude. I think you need to forget this idea.

 

[finfanatic]

You need one of these:

http://ioinc.us/mm5/merchant.mvc?Sc...Product_Code=ROMA0008&Category_Code=Long+Guns

SSG-2000 Rifle, 7.62 x 54R - US MADE

 

[NCsmitty]

Quite a few French MAS 49/56 have been converted to 7.62x51 Nato (308). Some were done well and others have had some problems.
A 7.62x54R conversion may be possible, but not practical because of the large rim.


NCsmitty

 

[MMCSRET]

Reloading the 7.5X54 is on a par with 308 or 7.62X51. Both are inexpensive and easy to load. I'm thinking that loading 7.62x54R is more expensive than either of the former. I load for all three, I have never done a cost comparison because it just don't matter as long as they all go "BANG" uniformly.

 

[jpwilly]

7.5X54 French Mas ammo can be made from 6.5X55 Swedish Mauser brass. Simply put the case into the 7.5 sizing die, it will open the mouth to take a .308 dia bullet. Use a mil-spec primer just in case.

 

[R.W.Dale]

PLEASE PLEASE don't tell folks that they can safely make 7.5 MAS from 6.5 swede.

Back in the day you might could have done so but no more. Domestic brass manufqcturers have gotten lazy of late and started producing swede brass with an undrsized .473" case head vs the correct .480" for the 6.5x55swede.

This would not be a big deal in most cases except that the mas round is another .007" at the case head over proper 6.5x55, So 7.5MAS brass so formed would be a whopping .014" undersized at the critical web area.

Besides it's likely cheaper and easier to get correct 7.5x54 brass from Grafs than 6.5x55 to reform

 

[MMCSRET]

krochus is right, the correct cases are available "NOW". Two years ago even Cabelas was selling 7.5X54 loaded ammunition made from Remington and Winchester commercial 6.5X55 cases. I started forming my 7.5 cases about 10 years ago from 6.5 cases and have a supply. My suggestion is to do which ever is cheaper, as they all work in all the rifles I've tried and I do use a Mil-Spec primer.

 

[gunsmithing]

The SAAMI specs for the MAS is .482 head diameter. I have no idea what Krochus is on, but give me half. People that spout out figures like that confuse beginning shooters, and they have enough problems already.
I make my MAS ammo from 8 mm. Yes it blows out the web. Never had any let go, in 100s of rounds. Loaded some 20 times just to see what happened. Cracked the case neck finally. No seperation on the web though. I did not load them over recommended pressures, about 3 percent less than .308 but enough to get any job done. Just trimmed, resized and fired.

 

[Ian]

Converting from a rimless round to a rimmed one would be a lot of work. You'd have to make a whole new extractor to get over the rim, and open up the bolt face significantly (which may or may not be safe on a Mas49; I don't know). You'd also very likely have problems with magazines. The rim and taper on 54R cartridges would require a significantly curved magazine to feed (look at .303 Brit Bren magazines), assuming you could avoid rimlock problems.