tell me about the MAS 49/56

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whats to be complete? besides the receiver and the stock theres maybe 3 pieces to the whole bolt carrier group.. theres a couple in the united states in civilian hands.. someone could just backwards engineer one of these and start making their own.. but pretty dumb on the frenchies part by not selling them
 
justin22885 said:
i dont care how bad the rechambering job is, since my first goal will be to rebarrel it anyway to something higher quality, properly bored, properly gasses, shorter, etc

besides, isnt the 7.5x54mm cartridge a .310-.311 bore, or somewhere around there?.. id rather have a true .308 barrel if im going to have a 308 rifleds

from what i read, the MAS 49/56 barrel is 23mm at the receiver, the AR-10 barrel is 1" at the receiver, if theres enough meat on the MAS receiver, wouldnt it be cheaper and easier to rethread the MAS receiver to take an AR-10 barrel?..since the AR-10s are already direct impinged it would just be a matter of cutting and shaping a gas tube to fit the AR-10 barrel on the MAS receiver.. makes future barrel swaps a lot easier too, beats the costs of having a custom contoured barrel made up.. what do you guys think about that idea?
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It's your time, but I believe you are going to invest so much to do these things..... It might be better to go with something more standard....
 
"whats to be complete? besides the receiver and the stock theres maybe 3 pieces to the whole bolt carrier group"
I'm referring to the whole "we need duct tape and bailing wire to keep the guns from falling apart" bit; apparently small pins, parts, and the stocks have a nasty habit of working themselves loose --mostly because the guns are so badly worn out. MAS went bankrupt like a decade or so ago, and the French have literally been cannibalizing rifles to keep service guns running now that replacement parts are gone (I'm sure this has far more to do with an unwillingness to pay for them to be made than of MAS' bankruptcy, but you get my point)

Last I heard, the ARX160 was gonna get the nod. Although the French appear to be flailing wildly between designs, at least it appears they are fairly consistent about the replacement duration (every 30 years or so, it seems)

"you say standard, i hear boring, and plain"
This guy gets it. "It's not about the destination, man, it's the journey..." It's not like he doesn't have an excellent go-to rifle, already :rolleyes:

TCB
 
so, does anyone think it would actually be possible to bore out the MAS receiver a bit more and rethread it to take an AR-10 barrel (without its extension)?.. it would be interesting if it could be because that would be easier and cheaper than having a barrel blank custom contoured, makes future replacement and some aftermarket parts available too, such as gas blocks, muzzle devices, etc
 
How wide is an AR10 barrel extension, and can you thread the barrel in far enough before hitting the end of the threads? That should give you an idea of feasibility.

TCB
 
thats not something ill be able to measure without a MAS barrel in my possession.. but the threads on the AR-10 barrel (extension removed) is 1", and one source of measurement says the MAS barrel is 22mm at the threads, i have no way of telling the length of the barrel but if i had to guess the threads on the AR-10 to be too short or too long, id say the threaded portion is more likely to be too long, if this is the case, then it would probably be easier to cut the shoulder back and re-thread the AR-10 barrel for the MAS receiver

__

doing all the research i could online, i found three sources claiming the thread diameter for the MAS 49 barrels to be 22mm, and i found one source claiming the thread length was also 22mm
 
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I was referring to outside dims. So long as the MAS is fatter than the AR extension, you're strength is probably fine. I suspect another three millimeters in diameter will be fine, but you may not clean out all the MAS threads doing so.

TCB
 
i found one source for the dimensions of the AR-10 barrel extension that says the inside is tapped for 1"-16TPI threads, looking up a chart of these threads shows a major diameter of 1" and a minor diameter of .94", 22mm is the outside diameter of the MAS-49 barrel and 22mm converts to .866", this means that all the threads SHOULD be removed when rethreading the MAS-49/56 receiver to use an AR-10 barrel

however, from what i can tell the AR-10 barrel threads are longer than the MAS 49 threads by about 3/8 of an inch, so, a roughly 3/8" thick recoil lug should make up for this.. so if my numbers are in fact correct, then there should be no issues machining out the MAS-49/56 receiver, rethreading it to 1"-16TPi threads, adding a ~3/8" recoil lug as a spacer and installing an AR-10 barrel onto the MAS 49/56 and adapting the gas system.. and since its a tilting bolt design, headspacing should be doable on the locking surfaces themselves

if anyone has information contrary to the numbers ive mentioned about any of the dimensions in questions, by all means correct me

oh, and i forgot to mention the outside of the original MAS 49 barrel had a 27mm outter diameter at the shoulder, looking at photos this appears to be the same size, if not a tad smaller than the area of the receiver around the chamber, so there should be plenty of meat on it
 
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7.5x54 bores are actually a bit tighter than most .308, but not so much that .308 bullets can not be used.

Reloadable cases can be made from European made 6.5x54 Swede which has the correct body and base diameter, US made 6.5 swede tends to be smaller.

For all the effort of rebarreling an exisiting 7.5 MAS49 one could buy forming and loading dies and crank out a good bit of 6.5 based 7.5Fr. Do use a military still primer though.

-kBob
 
id have no interest in making 7.5 ammo though, i like to stock up on larger quantities of one ammo and use them in more rifles.. im more of a consolidator when it comes to the ammo i use and theres no reason to have 7.5 if it can be had in 308.. the amount i save in ammo costs alone will pay for the conversion and modifications
 
so, does anyone think it would actually be possible to bore out the MAS receiver a bit more and rethread it to take an AR-10 barrel (without its extension)?.. it would be interesting if it could be because that would be easier and cheaper than having a barrel blank custom contoured, makes future replacement and some aftermarket parts available too, such as gas blocks, muzzle devices, etc
Click to expand...

Except that the MAS uses a threaded barrel that goes right into the receiver, and the AR10 uses a barrel extension that is essentially "sandwiched" against the receiver by the barrel nut. Two different methods of attachment=not a simple operation.
 
shotgunjoel said:
Except that the MAS uses a threaded barrel that goes right into the receiver, and the AR10 uses a barrel extension that is essentially "sandwiched" against the receiver by the barrel nut. Two different methods of attachment=not a simple operation.
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actually, we're discussing the AR-10 barrel without its attached extension, the thread patterns ive listed are for the barrel itself, what i'd be doing would be threading the receiver of the MAS to match the thread pattern of the inside of the barrel extension, then take the AR-10 barrel, remove extension, and install AR-10 barrel directly to the MAS receiver, use a recoil lug to make up for the AR-10 having a longer threaded portion, and headspace on the locking lug (since its a tilting bolt)

sounds pretty simple to me and if im not mistaken the AR-10 barrel nuts are torqued on so it shouldnt be all that hard to remove with the necessary tools
 
Justin, I don't mean to insult, but you make zero sense to me.

I get that you just want to do this for the sake of doing it, and I can respect that, but you seem to be all over the board with this. You reject the practical as "plain and boring," even though your plan will cost far more than the gun is worth, yet, you insist keeping the gun in 308 because that is the practical, common caliber. I'm shaking my head. I don't understand why you don't just buy an M1A and call it a day.

I'll never understand why people reject the "plain and boring." But hey, I'm enjoying the discussion, and wish you luck.
 
and what exactly is "value".. how much i can get out of it if i resell it?.. why would i want to do do that? the end product will be a 308 caliber battle rifle thats more reliable, more accurate, and lighter than most comparable battle rifles.. that value alone in having an accurate, reliable, durable, lightweight 308 battle rifle is what im after, not collector value, not resale value, but its value to me in what it brings to the table, what it can do for me

i have nothing personally against 7.5x54mm, i just have absolutely no use of this caliber, im not the type of person to have 10 different rifles in 10 different calibers having to supply them all with hard to find ammo, if it can be had in something more common like 308, then thats what i'm going to have it in.. again, 308 conversions from obscure and obsolete calibers tend to pay for themselves in ammo savings alone
 
Variety is the spice of life. I rely on the plain and boring AR and Glock. I relish the unusual and interesting MAS and Webley. I can understand why Justin would want to enjoy the process of customizing a MAS 49/56 but not wanting to complicate his ammunition logistics. I hate reconfiguring my Dillion so much I would rather just buy another press for a different caliber and I really don't need to be buying any more presses. Nothing wrong with the people who like to keep things authentic but some of us don't feel the need to do that with every firearm.
 
so.. im curious, how well do the dust cover sights on the MAS hold zero? one problem i'm evidently going to have with replacing the barrel is the loss of the front sight, so im going to need new sights.. it looks like the axis of the bore of the rifle and the top of the dust cover would be pretty close to the same difference as on the AR rifles, so it MIGHT be possible to remove the rear sight for a short length of rail with a railed gas block for a set of rail mounted backup sights, but if the dust cover does too poor of a job of holding zero then i may just get a red dot that has its own built in backup

and how good is the rear sight?.. if its a quality, accurate rear sight then i may just find a way to add the old sight to the top of the gas block, if its similar to the AR rear sight then i may just modify an A2 sight/gas block to match the height of the rear
 
Just reinstall the front sight? I'd reinstall the gas shutoff valve too and thread it 5/8x24 tip. Would make an awesome suppressed gun!

There were two MAS 49/56 receivers for sale on gunbroker a couple days ago for like $160 or so for both.

Fantastic project! The guns are already messed up from century anyway.

Please post pictures of the conversion process.

Dan
 
i dont see much need in all that excess weight of the grenade launching components of the front sight.. i could possibly make a front sight block to house the MAS front sight without the grenade launching components, ive noticed the MAS front sight has almost an identical design to ARs, thats why i was just saying adjusting the height of an A2 sight/gas block to match should work fine, and i prefer such parts to be pinned on anyway

why would retaining the original gas shutoff be important? doesnt anyone make AR-15 gas blocks with this feature? seems useful for 300 blackout builds.. besides, it doesnt seem a subsonic cartridge with 220 grain bullets out of a 1 in 12 or even 1 in 10 twist barrel would be very stable, probably better to just get a little 300 blackout bolt action if i wanted suppression.. that actually sounds like another cool project to do afterwards, a integrally suppressed .300 blackout bolt action rifle, like a delisle carbine but with much more range and accuracy
 
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Don't mind the skeptical, impatient haters, er, skeptics. A year or two to get started on a design is nothing for the home hobbyist. I spent about that much planning my Skorparev build, and most of last year building parts (with hand tools) for it one at a time, and just this evening got it to where the op-rod sorta-kinda-reliably unlocks the bolt properly (most of the time). This stuff takes man-years for dedicated corporations with resources to develop, which is why they so rarely bother to. An individual hobbyist can eat the elephant, but it takes a while (and you may abandon one elephant to tackle another part way through as your tastes change over the years)

Extremely rare is the guy who can whip a scratch build up in a few weekends (and he is almost always retired and working approximately towards a simple, proven design). They're the ones who trick us mere mortals into thinking this won't be such a difficult/expensive hobby ;)

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Guys, the reason he wants to use AR10 barrels is because turning a barrel from a blank is a colossal chore compared to most of what else he's described. Being able to use a readily-available, inexpensive (due to less work involved), and quality item as-is or nearly so as a component or raw material in a build is just simple common sense.

No, simply buying what is available to you in stores all wrapped up in a nice, plastic wrap is not necessarily "common sense." Such solutions do not always deliver what an individual desires (in fact, I would submit they usually don't, if we're picky and honest enough)

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Justin22885, finally addressing the build;
I have one --"concern" is too strong a word-- with the AR10 barrel idea. Unless you use shims to seat the barrel precisely (an art form of its own), you will have to "clock" the threads in the receiver such that the gas port ends up fairly close to where you want it. This can be done, but is very difficult for most hobbyists, and is the primary reason why 80% FAL builds are so uncommon (threading the receiver). Very specific lathe functions are required, as well as the skill to use them. I think the shim idea is more desirable simply because you can keep throwing shims at the thing and tweaking them until it goes together right; one wrong move on the lathe and your hard-to-find receiver is trashed. It also sounds like you'll be needing some sort of shim anyway, to ground the barrel shoulder of the AR10's longer threaded area. Also a convenient place to fix your forearm to, btw (like a smaller version of the AR barrel nuts with external threads for free-float tubes)

If you do seat the barrel with shims, you will need some provision for headspacing the bolt (highly unlikely that the gas port and headspace will coincide at the same barrel position). Rather than cut on the parts you can't replace (the bolt/receiver) I'd do what Garand builders do to resolve the exact same conundrum; use a short-chambered barrel and ream it to depth. I know Green Mountain sells unchambered barrel blanks for .223 AR15s already threaded and fitted with extensions (sadly no barrel profiling), and they may do them in 300 Blackout (or 308 for AR10s) which could work for your purpose.

I understand a bit of experience is needed to do it reliably, but it's a pretty basic gunsmithing procedure for custom guys. He torques on the barrel to within 1/4 turn of gas-port alignment, and measures how far he needs to ream the chamber for proper depth. The barrel is then (usually) removed and popped in the lathe, where the reamer is run in the aforementioned depth plus that extra quarter thread pitch (plus some extra to account for "fudge factor" from the second torqueing of the barrel, receiver/thread deformation under full torque load, etc. --this is where experience is needed). At least if you go too deep with the reamer here, you can easily cut the AR10 barrel back a full thread and try again (and with the extra thread length over the MAS, you'd get at least a few bites at the apple per barrel before more threading would be required)

TCB
 
well my idea was to use something like a recoil lug to act as a shim to make up the extra space between the AR-10 shoulders and the receiver as the AR-10 threads if my information is correct are longer, my idea was to adjust the thickness of this shim until the barrel can be properly toqued with the gas port facing upwards, then the headspacing would come from the bolt itself, since its a tilting bolt this wouldnt be all that difficult.. ive already figured getting headspacing AND the gas port aligned would be impossible any other way
 
justin22885 said:
that could be a long, off topic paragraph, PM me if youre GENUINELY curious about the progress
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I only ask the question, because as others have pointed out, you seem to be going about this the "long" way

Which.... is entirely up to you.....

I would start this with (Unless you are a pure collector) ...... What clear role does the weapon you are choosing have?

Knowing this may help you to be happier with your purchase 2 years after you made the decision

I had a 24/47 Mauser that was in good shape, but decided I wanted to "smith it"

I did a great amount of work, bedding the action, cutting and milling to do a proper scope mount, getting a bolt handle cut and welded at a different angle for scope clearance, installed a new lighter trigger, plus many other things.........

The rifle shoots at less than 1.5 (best group at 1.1) with my reloads

But, after doing the project....... I have a rifle that is worth $350 that I put $500
plus into, before my hours of work.

If I had it to do over again....... I would have just bought a 308 Bolt action.
(Boring, but functional)

I had a SKS that I did numerous smithing activities on I bought it for $300 and put another $200 into it (I HAD to have the Tapco stock :) )...... and sold it for $375

I have a high-end incredibly accurate AR15 (in 6.8) that I assembled and have much more in it than I could sell it for

It does less than 1 inch groups at 100 yards with a 4 power scope. (I think I could probably do 1/2 inch with a higher power scope)
The Texas pigs that I hunt would probably be "just as dead" with a rifle that shoots 2 inch groups.

I did trigger work on my M&Ps and would take a loss if sold

I enjoyed the process on all, I learned much, but......... would probably approach the detailed smithing work differently

I would probably have started with more of the fully functioning "boring" purchases and just trained for CCW and hunted

You have mentioned in your threads that you are counting the costs. (reloading vs store bought, Bersa vs SIG, $1000 "Limit" on this rifle)

IF..... IF, you have the time AND the skills. go for it......

BUT.......

If you are going to a smith to have the barrels replaced and some of the other work
done.... your costs will be MUCH higher than you may have calculated

I speak from experience

I also was looking into a 308 "Battle rifle" I did the AR thing, but want something a little different.
(The PTR91, seems to fit my goal)

There are people that are trying to give you advise here, that is all.

Good luck with your decision
 
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"the headspacing would come from the bolt itself, since its a tilting bolt this wouldnt be all that difficult"
Please describe how this will work, if you don't mind. Is there a replaceable locking block in the MAS (like the BREN)? If so, is it easy to find replacements or fabricate? Any other shaping of the actual lug surfaces will be hard to do as good as the factory.

TCB
 
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