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Posted: 11/16/2011 12:32:00 PM EDT
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I'm working up a MAS 49/56 and hoping to see some better accuracy downrange.
PRVI Partizan ammo shoots a bit underwhelming––I'd say 4 MOA. I'll be trying out some handloads this weekend (Hornady 150 gr BTHP). I've noticed some change in accuracy based on sliding the "gernade" launcher ring and altering the barrel harmonics, and I am going to try tightening up the slop in the collar to accomplish more consistency in the recoil impulse, other but I'm hoping someone has some tips and tricks to share. Anybody? |
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Slug the bore maybe bigger than you expect Agreed––that's possible. But I am getting curious signs that there is accuracy to be had from this barrel. Shooting quick and dirty batch of reloads I got charge which threw a horizontal dispersion 8" wide but with a vertical dispersion of only 1.5 inches. I came close to replicating the dispersion pattern––not perfectly, but close––shooting PRVI at 200 yards and by sliding the gnade launcher-ring out to half- and 3/4-way on the barrel. I'm wondering if glass bedding the wood on the front end (or shock isolating it with rubber o-rings) might be something worth trying. I'd welcome any input. |
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Slug the bore. Also check for bolt movement in battery. Turn off the gas and see if the bolt jumps on it's lock. Possibly replace parts with less worn parts. Interesting––I'm new to the MAS 1/IV, can you explain more fully what I'm looking for? Weak lock-up? |
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1) ammunition. You may be want to load your own. 7.5 French is little fat and it should not be based on .30-06/8x57 case (.473) 2) Rear sight base. The rear sight base is the receiver cover. Does it move. You won't get consistency. Definitely check these these two factors before proceeding. Some 49/56's like heavier bullet weights than 139 gr., so don't be afraid to try that. The stock shouldn't need any bedding; they're usually on there nice and snug. Mine shoots less than 2 MOA with the grenade collar in any position, so I don't think messing with that is going to yield much. The previous MAS I had shot the same. Have you tried shooting French-made surplus? It's corrosive as hell, but it shoots great. |
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1) ammunition. You may be want to load your own. 7.5 French is little fat and it should not be based on .30-06/8x57 case (.473) 2) Rear sight base. The rear sight base is the receiver cover. Does it move. You won't get consistency. Definitely check these these two factors before proceeding. Some 49/56's like heavier bullet weights than 139 gr., so don't be afraid to try that. The stock shouldn't need any bedding; they're usually on there nice and snug. Mine shoots less than 2 MOA with the grenade collar in any position, so I don't think messing with that is going to yield much. The previous MAS I had shot the same. Have you tried shooting French-made surplus? It's corrosive as hell, but it shoots great. Lew––I haven't shot any of the French surpus ammo, nobody around here has it in stock. I'll keep my eye peeled though. Had some good shop time today. I rebuilt the rear sight, installed a new ball detent (a chrome ball bearing) and cleaned out the hole/recess. The sights give much more positive clicks and there is no slop. There is some discernable side-to-side play in the sight cover. I'll have to figure out a strategy for that––maybe shims (?). I also gave the rifle the "two minute trigger job"––dropped out the trigger group, slid the safety lever out half-way and released the left-hand leg of the trigger spring. Trigger pull is much smoother, half the weight––but of course the safety only has half the tension/resistance as well. It is easy enough to go back to the old trigger-pull. I'll see. I used a rubber o-ring in behind the gernade ranging ring. Thickness of the o-ring was 3/32, and just big enough to fit over the barrel––and I compressed the rubber with some serious pressure (pushing against the ranging ring with a wooden tool I made up) and it compressed the rubber good and tight and the ranging ring clicked distinctly into the last notch under tunz o back pressure and it is now tighter than hell. Zero play. I'll see how the o-ring holds up to heat––might have to go with a viton or something. If it makes a difference one way or the other in accuracy I'll post the specs for the rubber o-ring (if anybody is interested). That's about it. If the range trip yields any good results I'll post them up. ––Eight_Ring |
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Interested to see your results. I've been trying to find a load using WC844 and 165gr NOS SP's. Nothing good to report. 55_Grain–– My first loads were built using PRVI brass, Hornady 150 Gr. BTHP, a CCI mil-spec primer, and IMR 4895. The startign load was 37.5 grains, and it shot like a shotgun. I found that all the low-end loads in the Hornady 7th Ed. manual were chronographing 400 FPS slower than where they should have been. No idea what was up with that. I'll post chrono data for PRVI and handloads if you're interested to see it. There is a guy on the boards who was telling me not to get discouraged, that his loads shot consistently awful until he got above 41 grains of IMR 4895––then it all converged and started shooting MOA. Go figure. ––Eight_Ring |
| I also tried dropping the left spring arm. It did make my trigger pull lighter. I do like it but the trigger reset dose not always work. Sometimes i have to push trigger forward.Hopefully it will smooth itself out. I also brought down the firing pin tip. i have had some slam fires. Since i did this no more. Also i uniform all primer pockets. Some are not deep enough. My load right now H4895 41gr alittle over 2300 FPS Brass barely stretches so next load i neck size. Average groups 3 to 4 " at 100yds good enough for military matches. Using pulled 147gr seated to mid cannelure Also make sure you run the firing pin dry. |
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I also tried dropping the left spring arm. It did make my trigger pull lighter. I do like it but the trigger reset dose not always work. Sometimes i have to push trigger forward.Hopefully it will smooth itself out. I also brought down the firing pin tip. i have had some slam fires. Since i did this no more. Also i uniform all primer pockets. Some are not deep enough. My load right now H4895 41gr alittle over 2300 FPS Brass barely stretches so next load i neck size. Average groups 3 to 4 " at 100yds good enough for military matches. Using pulled 147gr seated to mid cannelure Also make sure you run the firing pin dry. Krallstar–– I'm new to the MAS (and sorry if this is totally off base) but have you ruled out adjustments to your trigger protrusion? Troubleshooting trigger problems inre protrusion 1... Trigger problems... Lots of experienced MAS hands over at gunboards (if you've never been over there), and they have a pretty good bead on where to find replacement parts. Inre: the firng pin/slamfire issues, I went with the modded firing pin offered by Murray's Guns. $25, and it seems like good insurance. Good luck. |
| Thanks for the links, from those pics what is happening is the rear sear is hanging up alittle. I have had this rifle for 10 yrs or more and it has always run fine other than the occasional slamfire. The only thing i did was drop the spring leg. Now when i squeeze the trigger and hold it back, after a second or two i release the trigger and sometimes it hangs, a little push forward and it resets. If i pull the trigger and release it quickly it resets every time. That spring must exert some pressure that allows the trigger to reset. I figure if i keep shooting it it should smooth up. |
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Interesting day at the range.
The ten second trigger job and eliminating vibration from the MAS's ranging collar with the rubber o-ring made a pretty big difference. Basically they cut my previous groups in half (shooting with iron sights). Most surprising of all was what happened when I cut off the gas to the action (flipping up the lever in front of the gas block). I had to use a cheap $25 NCSTAR scope on it because the iron sights were obscured by the valve lever PRVI PARTIZAN AMMO / MAS 49/56 / SHOT WITH NO GAS TO ACTION / ALL GROUPS @ 100 Yards 
I'd say the barrel is capable of nice accuracy. Here are two groups shot with the scope in semi. Ammo was the PRVI Partizan. 
For anybody interested in the tool I made up to seat the o-ring behind the "gernade" launcher, I'll be offering them for sale in the EE for $125 apiece. Just let me know how many you want. 
On to handload data. Cool fall day, 10 shot string, Competition Electronics Prochrono Digital. The PRVI clocked at 2378 FPS on average––2402 High 2351 Low, ES 51, SD 17. In short, my handloads shot like dogshit for accuracy (chrono data below) basically they were shooting a 4 inch tall group as wide as the eight ring with two or three alarming flyers which eroded all confidence in my marksmanship. I think i'm going to try loading some flat-base bullets rather than the (Hornady) 150 grain BTHP. Data: Once-fired PRVI Brass, CCI 7.62 milspec primer, IMR 4895 powder, all brass trimmed to within .001, bullet seated to specified OAL in Hornady 7th for 150 Grain BTHP (2.940) and given a semi-incompetent crimp. 44 Grains IMR 4895: 2294 FPS average. 2326 H, 2263 L, ES 63, SD 15 45 Grains IMR 4895: 2397 average, 2437 H, 2365 L, ES 73, SD 20 Light was fading, and chrono was acting flaky and dropping shots in the flattening light, so I don't actually trust this next set of data: 45.5 Grains IMR 4895: 2404 average, 2424H, 2368 L, ES 56, SD 19 *** Final thoughts: Cutting off the gas showed what barrel could do without the harmonic chaos/irregular vibrations caused by the action cycling. It should also be noted that the rifle kicked like a mule without the semi-auto reciprocation––and I almost got nailed by the scope, and I may well have pulled one of the five shots in the first group. What I am going to try next is to install an adjustable gas valve, to try to tune the action so that it gets just enough energy to cycle reliably, and then see what lessening that vibration does for smoothing out the groups. I'll post more if anything dramatic happens. I'd welcome any input on bullet or powder selection. I just used IMR 4895 bcause I happened to have it on hand. ––Eight_Ring |
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I'd welcome any input on bullet or powder selection. I just used IMR 4895 bcause I happened to have it on hand. It may not be helpful, but the MAS-36 runs best with Varget and 168gn SMK BTHP. I don't know what twist rate the MAS 49/56 featured, so that may not be a good choice of bullet. Unless there is a specific reason not use it, Varget will typically get good results (for me) from many calibres. I was given load data for the MAS on this site, so hopefully someone will have a more specific idea of what to use for these particular rifles. |
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lew––
A fellow with the internet handle "Kelt" (former French Para, I think, and he knows the MAS rifles forwards and backwards) gave the metrics in THIS thread which I beleive ciphered out to 1 in 11. ETA: Anaxes I have load data from Hornady 7th Ed. and the Lee reloading book––but I think part of the problem is that they are presupposing many divergent elements––bolt-action Mas 36 vs MAS 49/56, reformed swiss brass by Lapua etc. I'd be happy to scan it for you & email it if you want to take a look. ––Eight_Ring |
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lew–– A fellow with the internet handle "Kelt" (former French Para, I think, and he knows the MAS rifles forwards and backwards) gave the metrics in THIS thread which I beleive ciphered out to 1 in 11. ETA: Anaxes I have load data from Hornady 7th Ed. and the Lee reloading book––but I think part of the problem is that they are presupposing many divergent elements––bolt-action Mas 36 vs MAS 49/56, reformed swiss brass by Lapua etc. I'd be happy to scan it for you & email it if you want to take a look. ––Eight_Ring I've talked to Kelt on Surplus Rifle a few times. Helped me out a bit with my Algerian War kit. I'm not a member at Gunboards, but I drop in once in a wile. I would definitely appreciate the load information. I have a Lee and Sierra manual, but I can't remember for certain if the 7.5 is in there. Probably is, and I'll pick them up later this week as I transfer all my reloading crap out of my mom's basement. |
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ETA: Anaxes I have load data from Hornady 7th Ed. and the Lee reloading book––but I think part of the problem is that they are presupposing many divergent elements––bolt-action Mas 36 vs MAS 49/56, reformed swiss brass by Lapua etc. I'd be happy to scan it for you & email it if you want to take a look. I have the Hornady and Lee data, but thanks for the offer. The Hornady data is indeed for a '36 with reformed brass (as far as I remember). It has been reasonably helpful, but with 1lb of most powders at roughly the equivalent of $62 here, it's too expensive for much experimentation. |
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I have only shot my 49\56 a few times using surplus belted ammo.
Was very surprised at the accuracy, +\- 2.5 inch or so at 100 yards, off of sand bags. Careful, believe the ammo is corrosive, Can't recall where I bought it, came linked in 200 rounds. I surprised, AND, pleased. |
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I had some very interesting results at the range this weekend.
I installed an adjustable gas valve, and dialed back the gas pressure so that the action only had enough energy to cycle reliably. The brass was ejecting about as vigorously as a bolt-action, and landing atop the shooting bench. It did (as theorized) smooth out the groups considerably. The groups no longer look like a collection of ragged flyers––now there is a semblance of order there, suggesting circles of probability rather than randomized chaos. Accuracy is still a bit underwhelming––but it is WAY better than it was. I'll post pics tomorrow, if anybody is interested. To summarize: The rifle's baseline was throwing a rectangular box of flyers eight inches wide and four inches tall. The trigger work made the ragged pattern half the size––and quieting down the vibrations made the wildest flyers disappear. I'd say the "twenty second trigger job" was responsible for 40% of the accuracy gains––then quieting down the vibration of the grenade ranging ring (.25 cents for a rubber o-ring) added 40%, then the adjustable gas valve groomed the group patterns nicely and smoothed out the action (call that 20%). The adjustable gas valve has it's pros and cons––but overall I'd say it is worth the $25. YMMV. Anyhow. Thanks for reading. If anybody reloads for the MAS 49/56 I'd be interested in hearing your experiences with various bullets and/or powders. ––Eight_Ring |
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Where does one get this adjustable gas valve? A guy on the French Firearms section of the GunBoards makes them––his handle is "Starmetal". The cost is $25. I don't think he realized that they could be used for accurizing––it was sort of a hunch I was following after my experience with the Schuster nut on the Garand. LINK. If you are interested I'll rustle up his email address. |
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Where does one get this adjustable gas valve? A guy on the French Firearms section of the GunBoards makes them––his handle is "Starmetal". The cost is $25. I don't think he realized that they could be used for accurizing––it was sort of a hunch I was following after my experience with the Schuster nut on the Garand. LINK. If you are interested I'll rustle up his email address. I would appreciate the address. I figure since I now have two- one refurbed, the other not- the first (refurbed), which already performs admirable, can be tweaked a bit to wring the most out of it. |
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Berzerker––
Starmetal says he is no longer making the gas valves because he sold his MAS and no longer has the parts to reference, but if you want some pics of the actual device I could maybe post some (though it may take awhile). The original French gas valve was fairly simple, just a hollow milled in the round plug, and when you rotated it 45 degrees the round section closed off the gas port. Ought to be simple enough to build one our of a proper sized bolt body and a dremel tool. ETA: I'll try to throw a Mic on the gas valve so you have some specs to work from. Quoted:
I'd like starmetal's email as well. Someone removed the gas cut off on the one I got for a song and right now it's a single shot! |
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Berzerker–– Starmetal says he is no longer making the gas valves because he sold his MAS and no longer has the parts to reference, but if you want some pics of the actual device I could maybe post some (though it may take awhile). The original French gas valve was fairly simple, just a hollow milled in the round plug, and when you rotated it 45 degrees the round section closed off the gas port. Ought to be simple enough to build one our of a proper sized bolt body and a dremel tool. ETA: I'll try to throw a Mic on the gas valve so you have some specs to work from. Quoted:
I'd like starmetal's email as well. Someone removed the gas cut off on the one I got for a song and right now it's a single shot! I have seen a picture of one and as I will never need to use the cut off I should be able to fab one up pretty easily. Too bad the lathe is not set up yet or I would have this done already. OD of the pin would be great. I figure I can add a few thou and make it a press fit to get it up and running. |
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