MAS 49\56 project...

[m1a1driver]

Just thought i'd share this. I picked up a Century converted .308 MAS49\56 a few weeks ago. I know there are some inherent problems associated with these converted rifles, but was willing to undertake this as a project. Upon initial test firing, the first 40 rounds functioned flawlessly. Ammunition was a mixture of Winchester 150gr SP's, German surplus, and American eagle .308 ammunition. All fed, fired, extracted, and ejected fine. After the first 40 rounds problems began developing, the brass would get stuck halfway out of the chamber during extraction, with the extractor exerting excessive force on the rim which bent it back, but did not rip it off. The extractor did slip off the rim of the case though. It didnt happen every round, but after 20 more rounds they became much more frequent, then it got to the point where I just put the rifle away. After much researching I found out there are a number of problems, the cut-down recoil spring, excessive gas from the hotter .308 round, and a rough chamber due to century's crappy finishing reamer job. I had my gunsmith polish the chamber, and I found a guy on gunboards that makes a custom adjustable gas valve. I installed the valve today, and took some material off the backside of the extractor which should allow for a better "grip" on the case, and I am going to test fire the rifle on sunday if time permits me. I'll post updates as they happen. Here are some photos of adjustable gas valve, and the polished chamber, and the modified extractor with some spent brass.

[billybob_jcv]

For some reason, I thought these types of conversions were intended for 7.62 NATO ammo, not commercial .308 Win?

[m1a1driver]

I wasnt sure at first, but the receiver is marked for .308. The 7.5 is overstamped to 7.62 and underneath is stamped .308 the magazines are also stamped with .308 CAL. (the converted magazines)

[billybob_jcv]

I think this is what I was remembering - it is from the wikipedia article on the MAS 49:

http://en.wikipedia.org/wiki/MAS-49_rifle

[m1a1driver]

Interesting. I dunno why century would mark it both .308 and 7.62..but then again, it is century arms we are talking about. The gas valve should do its job by only allowing a limited amount of gas to enter the action.

[smle-man]

Hope you get it to work. Where did you get the replacement gas valve and recoil spring?

[Rogerbutthead]

I see that you have that May 2005 American Gunsmith article on fixing those Century Conversions. Did you have any comments regarding what they said to check on the rifle?

[m1a1driver]

you know what, perhaps you are right. Maybe i'm using the wrong ammo after all, i've been shooting .308 win, I'll try some 7.62 nato ammo next time and see if it has any extraction failures like the .308 does. I got the adjustable gas valve from a guy on the french forums on gunboards. Hes a good guy, my valve didnt work so he is going to fix it. Test fired it today with 100 rounds of federal .308 win using the original stock gas switch. I did have some extraction failures but not as many as the first time, seems like they started happening when the gun gets hot. I will try 7.62 nato ammo and some steel case ammo next time. ( I was told the steel case doesnt expand as much as brass and wont get stuck in the chamber) so we shall see...

[billybob_jcv]

FWIW, here's another reference:

http://jpfo.org/filegen-a-m/masrifle.htm

And please - I'm just trying to help by doing some googling - I have no first hand knowledge - so please be careful!

[billybob_jcv]

So, just to confuse things more, here's another web site:

http://www.thetruthaboutguns.com/2011/08/joe-grine/gun-review-mas-4956-fusil-semi-automatique-modele-1949-1956/

The vast majority of the problems associated with MAS 49/56 arise from bubba’ed .308 conversions. Century Arms converted a bunch of imported MAS 49/56s to .308. Win. in the 1990s and the results were pathetic. Some work, some don’t. Bottom line: stay away from CAI conversions unless you can verify that they are “shooters.”

I'm not sure that's a reliable source - he seems to own an *unconverted* MAS 49/56, so he may not have good info.

[Milspec714]

Who's your gunsmith? LOL... so what happened? stuck rounds still? after how many shots? was it better than before? lost my phone so im in the dark... your buddy can pick up his FAL tomorrow had to order the parts..

[dfletcher]

I have an original chambering MAS 49/56. As I understand it using 308 or 7.62X51 causes an issue not because of higher pressure but because that pressure is reached faster - faster pressure curve. In the 7.5 French chambering the pressure moves the bolt to extract just after chamber pressure has dropped a bit, allowing the case to be extracted. In a 308/7.62 version the bolt moves back while chamber pressure is peaking and the case is pushed against the chamber walls making extraction difficult.

I'd bet, so long as the chamber is properly smooth, that reloading would help the problem. I know that mitigates one of the reasons for having the conversion, no cheap surplus ammo. But reloading 308 down a bit is easier and cheaper than reloading 7.5 French. I hate losing the 7.5 brass, 308 brass - heck, who cares, there's always plenty about.

[aghauler]

Interesting. I dunno why century would mark it both .308 and 7.62.but then again, it is century arms we are talking about. The gas valve should do its job by only allowing a limited amount of gas to enter the action.

Because Century was using the perceived "interchangability" of .308 Win and 7.62 Nato as a way to unload these rifles on the uninformed. As an 01FFL back in the early 1990's I bought one from Century Arms, basically had the same issues you describe plus an out of battery discharge when I hit the op handle to load the next round. Scary and it also turned the palm of my hand black and blue for almost 2 weeks. The rifle went back to Century for a refund.