MAS 49/56 slam fire issue.

[geofry666]

I had my hammer spring on my MAS 49/56 snap while at the range a while ago. Since I had no luck finding a replacement spring I had to buy the whole trigger/hammer assembly from Apex. I replaced the entire original assembly with the "new" one. Well, upon my test fire at the range I got slam fire/2 shot bursts, using non-surplus ammo which worked well in the rifle before. So, now I swapped the new spring onto the original trigger group. I'm hoping this is the fix. Anyone else have this happen? Is this just because the spring had more tension than the old one?

[Richard Erichsen]

I had my hammer spring on my MAS 49/56 snap while at the range a while ago. Since I had no luck finding a replacement spring I had to buy the whole trigger/hammer assembly from Apex. I replaced the entire original assembly with the "new" one. Well, upon my test fire at the range I got slam fire/2 shot bursts, using non-surplus ammo which worked well in the rifle before. So, now I swapped the new spring onto the original trigger group. I'm hoping this is the fix. Anyone else have this happen? Is this just because the spring had more tension than the old one?

Were you not able to find a spring shop, hand them the spring and leave with a dozen brand new springs for a few dollars? I have three in my area alone and do this all the time. It's saved me untold $$ (I do the same with automotive hoses on my old cars, though the two shops are not co-located, which would be swell).

A new spring will take time to settle in to the correct length. They always start out a little long. The real culprit is the spring rate of the spring is designed for hard milsurp ammo and you used commercial ammo which generally has a much softer primer. You should use milsurp and introduce the commercial ammo AFTER breaking in a new firing pin spring and only cautiously. How do you test new ammo? One round in the magazine so that burst fire can't happen. Then two rounds and then four, but no more. If you get any temperament out of the rifle, back off and go back to milsurp. This method of trying a single round at a time at first, after you've put several hundred rounds of milsurp through the rifle, will keep you out of trouble with the RSO and any LEOs nearby.

R

[Rekrab]

Looking up this rifle, since I'm not familiar with it I found this at Wikipedia:

Commercial 7.5x54mm "French" ammunition made in countries other than France for current distribution have been known to produce burst fire (2 or 3 rounds at a time) because of more sensitive primers.[3] The original heavy steel firing pins on the MAS-49 and 49/56 can be replaced by commercial ( McCann Industries) titanium firing pins which are much lighter and generally cure the problem of burst fire on these weapons. It is also possible to prevent these slamfires by shortening the firing pin by approximately 0.5 mm, or by modifying the bolt to accommodate a firing pin return spring. Coincidentally, the Simonov SKS semi-auto rifle also features a freely floating firing pin which is prone to generate slamfires if not kept meticulously dry cleaned with a solvent. It is imperative that the firing pin channel should always be kept entirely free of sticky grease or oily residues. In other words: the cleaner and freer the firing pin is on the Simonov SKS, the less prone it will be to slam fire. Experience with the MAS-1949 and 1949-56 rifle series has shown that identical precautions can also help alleviate the burst fire problem.

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

[Richard Erichsen]

Looking up this rifle, since I'm not familiar with it I found this at Wikipedia:



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

Many of these rifles were rechambered in 7.62 NATO due to the lack of access to 7.5 mm French ammunition. Milsurp can be found in this caliber, but it's rough. Like many military rifles, it was intended to be used with ammunition having a very hard primer compared to what is common on commercial ammunition intended for hunting and target use.

Shortening the firing pin creates new problems. The solution is either a steady diet of only the milsurp ammo (depending on whether converted to 7.62 NATO or not, this might be the best option), or buying a titanium firing pin with a somewhat stiffer firing pin spring (fractionally thicker spring wire diameter).

R

[geofry666]

This rifle is in original 7.5 French. Before this recent issue I had the problem where surplus primers were too hard, had the pin adjusted, but it wouldn't fire the primer, just dimpled it. Tried a few types of surplus with no success. I've been shooting non-surplus successfully for a while with this rifle. I have some surplus I can try next trip to shoot in the desert, since all the surplus I've found is magnetic. Thanks all.

[Seesm]

Mines works fine.... If you were local I would try to help.

[geofry666]

Mine was working like a champ. I couldn't miss with it.