Finnish M39 rebuild/experiment


June 4, 2011, 01:25 PM
Howdy boyz:
Here's some pics of my latest project. It's a standard issue Finn M39. BA barrel (belgium) It is unmodified and is as new in every way. I have completely aligned and bedded the stock to the barreled action. I'm staining the stock before I seal it up. It was a new birch stock in the raw. The bedding techniques I learned on 1903's I used here.
So here's my experiment. I have accuracy tested this at the range off the bench @100 yrds. Then I fitted and bedded the stock and accuracy tested it again. That cut the groups in half, 3"to 4" to 1.5" to 2". I'm using handloaded .311 dia., 174 gr. Sierra Match Kings bullets over 45 gr. of IMR 4064 on top CCI BR pri's in side of Norma brass @ 2550 fps.
Anyway, on these old military, turn-of-the-century rifles with full length stocks the forearm interaction to the barrel is crucial. That barrel has to rest in the barrel channel just so to be able to shoot round after round and the POI stays the same as the barrel gets hot.
Which bring me to what the ultimate goal is here. I want one of these M39's to shoot 1 MOA consistantly. My previous groups I tested with was using unmodifed iron sights. I have opened the rear half-moon apperture .020 in. It gives a much better perspective to the front sight blade.
Now here's the experiment. If you look you can see how the cleaning rod is secured into the stock by way of a threaded insert in the stock just forward of the recoil lug of the receiver. Now, I have noticed that if a person were to cut a groove in the cleaning rod at the correct spot a snap-ring could be installed on the cleaning rod. This then would allow the cleaning rod, to in essence become a tuning rod. Placing the load of torquing the tuning rod (formerly known as the cleaning rod) over the length of the forearm, and not just at the threaded insert. In theory I can't help but think that by adjusting the tension of that tuning rod it will affect accuracy .......... maybe good, maybe bad, who knows. However, I did order another cleaning rod from e-bay. IT"S TIME TO PLAY GENTLEMEN

If you enjoyed reading about "Finnish M39 rebuild/experiment" here in archive, you'll LOVE our community. Come join today for the full version!
June 4, 2011, 04:01 PM
I have a B barrel M39. All I had to do with it was install a Darrell scout mount and scope and shoot Privi 150 gr sp to get well under one inch groups at 100 meters........The Finns do build fine rifles.....chris3

June 4, 2011, 07:13 PM
Now this thread IS interesting :D

I use an M-39 to make my living , with Czeck Light ball.

My observations on this most accurate tool;

Accuracy is about 1-1/2 inches from the get go, but I find it grouping better after I better mated the handguards rear end to the metal retainer on the rear sight, as it was thick and longer on one side, and laid down much more evenly after a sliver of two was shaved off.
The bands can be used to adjust the stock tothe action as well as shims on the magizine and rear screws for better alignment of barreld action to stock fit.Shims made from pop cans are quick , easy and cheap.
You can also clamp down or loosen to freefloat the front band/wood to great effect, and dikkin with a screwdriver at the range is the most productive.

the Finns did not seal the wood, they used a mixture of oil, wax and pine tar. The nature of the Brich wood used is that it has little change with temperatures and relative humidity. Sealing the wood woulnt allow it to "Breath" and in extream temperatures the wood has more bending. The thin long Russian stocks suffer because of this, but they were not so worrried about accuracy as much as the Finns or Us here. To further the stiffining,and economize with the limited wood thaty had on hand, they built the stocks out of two often three splices of wood and thickend the stocks.

I found it prudendt to be sure to clean your tigger/sear surfaces, maby polish them a bit, make sure your trigger retaining pin is clean as well, clean it up if nessesary. Smoothness and a nice consitant let off is 1/2 of the shot.

I use my sight "as is" making a 6 o'clock hold with an even line below. I use the slide to great effect when I can figure the range and hold my sight the same every time.

I have a small house, and 11 people living in it, mostly kids, handloading isnt what it should be at the moment.
I have a friends house in Kotz that has a spare room were settiing up for such, and with my limited brass, I have been playing now and then, but first I handload small game rounds with cast bullets, 10grns of Unique, and being a handload , its VERY accurate to 100 yards.

Your load looks like a start when I send off for some of those MatchKings.

Im thinking:
If your going to use the rod as a Tuner, youll need a bering surface on the nose cap and on the rod. You might reinfore the rod retainers wood as well, so you dont pull it into the wood. Its the wood you'll be tuning, and just might be quite worthwhile.

I'm looking forward to your results!

June 4, 2011, 08:45 PM
Hi guys: Only iron sights on this. That's the trick, consistant 1 MOA groups, iron sights. I got plenty of stuff with scopes if I feel the need. But the purest cringes when he see's a scope on these rifles. The Finns definitely upgraded these rifles to another level. Very nice stocks. Good stocks to use to accuraize a Mosin. Mind you though these are not K31's either. But nothing else is.

Caribou I can see you're in the car with me. Yep the handguard is integral in the tuning process. What I found works very well on 1903's I think should work as well here. That is the assembly of the rifle is to allow the barrel to rest in the channel completely neutral with only a few lbs. of downforce between the barrel and the stock at the forearm when the receiver is torqued into the stock. Then the handguard's length is set so it just barely does not bottom out in the handguard retainer at the rear sight. And then shimmed between the handguard and the retainer to make the rear of the handguard sit tight on the stock. Then the front of the handguard is shimmed with felt pad to provide a slight downforce to hold the barrel in the bedding at the forearm but not so tight as to make rigid to the stock. Just dampening the harmonics.
I can see you understand what I mean about cutting a groove in the cleaning rod to provide a load bearing surface at the nose cap. My thought is that perhaps no more than say 10 lbs. of compression force applied between the threaded insert and the nose cap thrust surface will be enough to get some kind of idea if there is something there or not. Anyway it will be fun to see if I'm just crazy or what :rolleyes:
Here's a couple more pics of it just after I bedded the whole thing.

June 5, 2011, 10:09 AM
This is my other M39. I've gone through and basically blue printed this rifle also. I think I like this rifle better of the 2 however it shoots 4-5 inch high with the load listed above. When the sights are set on 4.5 it hits at 600 yrds. I may try the tuning rod thing on this rifle also to see if it can change the POI to bring the sights into spec. Both are "B" barrels. I believe that means the barrels were made by FN in Belgium. Is true Caribou or not? I picked both of these up recently

June 5, 2011, 06:51 PM
The "B' Barrels were not made bt FN, Belgiums Military works (in peace made arms for sport and export), but by civilian contracts in Leige Belgium, a steel and gun makeing center.
The barrels were always marked with the steel makers mark, "B",(Belgium) "Bohlar Stahl"(Germany), S.I.G (Switzerland), as well as the thinner M91 barrels that were fit for service were cycled into M-39 production, because the Army slimmed the fatter barrels that the M-27 and M28-30 had over the M-91 (the were thicker by a Millimeter in each side, so 2 MM thicker OAW)
"B" barrels are well known for a high nicle content that turns the "Blue" to a 'purple" on the metal, and are known to be the highest quality barrels on an M-39.
All barrels are proofed in Finland.

I dont have acess to bedding supplys, blueing or any chemicals that are unmailable, i use the shims insteda bedding compounds, but the rest is spot on with small improvements Ive made in the quest for Awsome accuracy.
Just a quick thought here;
Finn sights are held at "6'o'clock", Americans hold "on' the target....I.E. if i were useing an M-14 or 1917, I would center the front post and if I were shooting a Caribou in the middle of his head, I would hold on the center of his head, sights dialed to the range Im shooting.
If I were sighting with a Finn rifle, I would place the sights even and level at the Caribou's lower jaw line and the bullet will impact middle of the head, a difference in about 4 inches at 150yards, the lowest sight setting on an M-39. This can get American shooters to "Hit High". This hold was used so that , with practise, the target is not cover'd and a killing shot could be made from 50-250 yards, with the sights held at a Russians belt buckle, and the trigger pulled with a smile.
For precise shooting, I place the sights on the base of the bull at 150 yards and make dead center, 4 inches high. Using the same "combat setting" and 300 yards away, the sanme shooting place the bullets at point of aim,held at the base of the 8 inches of black Bullseye, on the target.

When were really goofing off I hold about 25 feet high and try 800-1,000 yard shots, which I can do with some practise, warm up and luck ~~LOL!!~~ but thats in Winter when the river is froze and we have "range"

June 5, 2011, 07:36 PM
Very interesting stuff Caribou. You are a veritable fountain of info., which is much appreciated. Good info. about the barrels. So if I understand, you are saying these "B" M39's are basically the latest and greatest incarnation of the Mosin Nagant series, yes?
I've thrashed the living dog crap out of 1903's and A3's for many, many years. I figured out how to blueprint those over time. A properly put together a 1903 or A3 is a formittable weapon and very accurate. The biggest set back on 1903's and A3's is the assembly of the rifle itself. They didn't do that real well. All very good hardware just not assembled like the precision rifle it is. Now the arsenal built national match 1903's were and still are considered to be one of, if not the most accuate military rifle of it's era. But I can't find decent 1903's any more to work with. So I thought I'd give the M39's a shot. Looks like a good platform towork with.
I've had several Russian Mosins, still got a real nice carbine which is a handfull of whipass :D, but these M39's are beasts. It's a BIG gun:eek:
Caribou, question: My understanding is that the Mosin action design is inherently very strong. Do you think it would be ok to bump the load up until it's generating 2700 fps with those .311 dia. 174 gr. Sierra Match King. Currently pushing that bullet at 2550 fps using 45 gr IMR 4064 powder, no signs of over pressure yet.
You know the mil-surplus GP11, 174 gr ammo for the Swiss K-31, they fly at 2550 fps too!! The Mosin has a longer barrel. I want to use that extra length to generate more muzzle velocity.

June 5, 2011, 09:19 PM
2550 is the normal speed , if I remember right, (near same for 7.62X51)for the light ball load the Russian developed.... bumping that 150FPS should be quite safe, but be carefull with that, as always.
I have no cronographic equipment so I plan to stick to 'Normal' and as best I can, duplicate the origiinal trajectory for predictable hits at ranges I am used to shooting.
I know the heavier bullets fly true'r Furth'r, but does Sierra make 150grn Matchkings in .310?
Belgium has sold Finnland barrels and steel since the inception of 'Finnland' proper. During arments revamping and organizing, "B" barrels went on Finn Army '91's and later rifles in Finnland, evidently on through WWII.
"B" barrels that were assembled into rifles after the war were from parts in stock. The year on the barrel denotes the year of assembly, under the tang you will find a date , usually the last two digits that it was manufactured.

You cant go wrong with an M-39.
Being rather beefy and heavy helps VERY much in help stedy the rifle for the shot. I feel it weight worth carrying as well, as long as I can do the job with a shot (or two) I'm very happy.

Theres a few vids I have of useing my M-39 to great effect in the archives here.

June 5, 2011, 10:15 PM
does Sierra make 150grn Matchkings in .310?

Not that I know of. I'd love to get .310/.311 dia. in 150 gr FMJ. We could make those quite speedy.
I'm going to snoop around and see.

June 6, 2011, 07:49 AM
First of all, this is a GREAT thread, lencac. Thanks to both you and caribou for taking the time to share your knowledge and experience with these rifles! I have a Romanian M44 that I absolutely love. Out of all the rifles I currently have/have had over the years, I've never felt a higher overall appreciation of any of them than I have of my M44. Caribou, I can tell you know what I mean. Unfortunately, now y'all have me "needing" a Finn M39!! I'm sure my bank account is gonna LOVE that!! :)

June 6, 2011, 11:02 AM
HI Luke:
I think if you can lay hands on a good M39, do it. They are still available but the prices are going up and the supply of good ones is dwindling. I think they are going to go the way of the Swedes and K98's, becoming harder to find nice ones and the cost is increasing. I recommend if you do decide to get one pay the extra $100 and get one that's like new, one of the late arsenal builds with the new post war birch stocks and new barrels. Remember any of these that were actually used, were used with corrosive ammo. Stay away from pitted or "dark" bore rifles.
Anyway, that's my 2 cents ;)

June 6, 2011, 11:11 AM
Finn sights are held at "6'o'clock", Americans hold "on' the target
Caribou, so what you are saying is need to start thinking like a Finn and not American.
I have heard before and understand about the different sighting techniques used, European vs. American.
In short you are saying my rifle is shooting exactly as intended, yes?

June 6, 2011, 12:22 PM
Interesting idea.

Have you definitely established that handload as the best with that rifle? If you haven't run various D166 loads through you should compare those as well. Plus some of these M39's seem to prefer light ball and equivalent handloads.

June 6, 2011, 01:19 PM
The load is a load I worked up sometime ago to provide consistent results in Mosin Nagants. It may not be the absolute most accurate for this particular rifle but it will be darn close and will provide what I need to complete my experiment.

June 6, 2011, 10:09 PM
Lencac and Caribou, excellent thread. I'm on the other end of the learning curve having bought my M39 about six months ago at I got a new unissued with a new bore (VKT) and new post war stock. I haven't reloaded for it yet, but it is amazingly accurate with 70s vintage Polish milsurp light ball. Every now and then, when the planets are in alignment, I can get 5 shots in a 2-3 inch or so group at 100 yards. I hope this thread continues...lots more to learn.

June 7, 2011, 04:18 AM
Maby not think like a Finn, but certainly to use the sights like a Finn would. _o_ rather than -o-

These were for precision shooting by a class of men who were still well versed inthe use of the Mosin.
They aimed for the beltbuckle, and , in the end kept their Liberty, so I guess if it were a war, Id shoot like a Finn ~~LOL!!~~

Im not one to speak much on reloads, my endevors are fairly new and I dont even have a basic standard velocity load, just stuff for small game, and limited use of that , yet.

However, I am willing to go th extra step of starting my cleaning with boiling water down the barrel to dissolve and flush the salts out with, and I do it at the end of each day, so my barrel is as new as it was when I recived it.
I use Czech Light ball "Silver tip" as I have found it s consisitancy and accuracy fall in great with its terminal effects on game I hunt, most noticably the effects of tumbling when it meets meat. :D
I was lucky and piled up Chzeck wjhen it was 62$ a case, but it wont last forever, so Im stocking up on components and such for the future, most likely alotta primers soon.
As well, Polish , Bulgarian and Albainian light ball all does well accuracy wise, but not quite what I get outta Czeck LPS.......hopefully I can duplicate the Czeck consistant velocitys with a better bullet, which aint bad at all......

Seriously, the only step up I can thisnk of is an M-28/76 biathlon rifle.......... someday ......wish the sold those on Gunsnammo :D

As well, the barrel is important, but the crown more so, as well as a nice even trigger.

A pistol grip on the M-39 Mosin is quite an improvement in handling as well as the side mounted sling making carrying it quite a bit more comfortable.......maby the only thing missing is a cleaning kit inna buttrap......

June 7, 2011, 09:33 AM
M1 Garand, M 39 , Lee No 4 and K 31 are all hard to beat. The M 39 shines, the ammo is still very affordable. Shoots like a house on fire.

June 7, 2011, 12:16 PM
it is amazingly accurate with 70s vintage Polish milsurp light ball.

I have also had excellent results with this ammo. The kind I found has a hollow base that seems to permit it to be used with a variety of Mosin diameters.

June 7, 2011, 02:42 PM
As well, the barrel is important, but the crown more so, as well as a nice even trigger.

I agree. I've noticed even on the Russian Mosins that the barrels look like little more than a piece of pipe but they put nice crowns on them.
The Finns apparently changed the triggers a little bit on their redos which are a bunch better than the Russian triggers. These 2 I have are pretty good triggers even before fiddling with them.

June 7, 2011, 03:43 PM
The M28 has the best of the triggers IMHO. They incorporated a simple little coil moustrap spring that works wonders.

June 7, 2011, 11:41 PM
I wonder about that Cosmo. I figure they just didnt have the time to work the triggers like they had in peacetime with the Civil Guards wringing as much accuracy as they could outta them.

Seems my Finn 91 ('09 Tula, all mathing with moustrap trigger spring, the only Finn mod and imported from there, no SA) my M-24 "Lotta" and M-28/30's have the sweetest of all triggers, as all were civil guards, and their ridgid accuracy standards.They had the time, and SAKO really tuned up M28's 28/30 to some seriouly awsome shooting platforms. My only preference of the 39 ove rthe 28/30 is the heavier front end being more stable in hold on targets. My one preference over the M-39 is the M-28's (and M-24)Triggers, for the "Feel", but with some attention My M-39 is near as good in take up and same same in break.
M-27, M-39's a couple 91/30's in Finn wood, no springs and noticably stiff trigger, but still with a clean break, so someone did pay them some attention at the factory (Thank God :D)

I gotta try an M28/76, Cosmo, I simply must.......:banghead:

June 8, 2011, 12:26 PM
I think the M39 stock is probably a bit better and gives it that stability. I'm pretty sure the barrel on the M28 is actually a notch heavier than the M39's. Mine seems to be anyway.

That got me thinking about lencac's project. I'll wager you would see more dramatic results with an M91 and that long thin barrel than with the heavier barreled models. I've noticed that changing the stock/barrel pressure on the Finn M91's I've had has had a pretty marked impact on accuracy.

June 8, 2011, 09:22 PM
The M-39's barrels are the thinner '91 type, not the extra 2mm on the beefy civil Guard rifles.
One thing I forgot to mention here, in our quest to wring our rifles for More, is that a comsistant pressure on the action screws is pretty important. I know a guy who actually has a tourqe screwdriver and sets his according to his 'secret poundage' ~~LOL!~~
I actually pay the tightening prety close attention, as I have tryed to 'train' myself to repateable tourque.
We were taught this in Biathalon, but never actually practiced it, as someone had shimmed our rifles long before and set the screws to bottom out for an exacting Over all length, no matter the tourque. Not so with the Mosin, it will crush wood with too much tightening.

June 9, 2011, 11:47 AM
I would agree about it having more effect on the Russian rifles. Except I haven't figured out a way to do it to a Russian stock. I'm not impressed with the type of wood the ruskies used though. The M39's lend themselves very well to trying this though with how the end cap is designed.
I use a in/lb. torque wrench to tighten the receiver screws. The front one is set to a predetermined amount and the rear screw is used to adjust how much down force is applied to the stock at muzzle end of the barrel. So the front screw is like the fulcrum. With both being held to a certain range of torque. If I can't get enough down pressure at the barrel with adjusting the rear screw without going over a predetermined torque I will add a couple of in/lbs. to the front screw and then redo the rear.

June 11, 2011, 11:02 AM
Howdy :)
Ok, I got my extra cleaning rod. Here in the la'boritory we do what we need to do. I need a mechanizm. Here's my 10 minute solution. I'm ready to rock & roll. Just need to wait to goto the hardware store to see what my choices are on snap-ring type stuff. Here's a couple pics of the jerri-rig.
"Bridgeport?:cool: We don't need no stinkin Bridgeports mang:what:"
Complete with variable speed "lathe"

June 11, 2011, 11:37 AM
here, the reason I installed a scout mounted scope is because my 67 year old eyes, after cataract surgery, won't allow me to shoot iron sighted rifles. When I still could see the sights, I could shoot my '43 Tikka 91/30 to the tune of one inch groups. It is hell getting old......It only will take about 5 minutes to reinstall the original rear sight on my M39.....chris3

June 11, 2011, 08:37 PM
So I go to the hardware store ............. just looking at "ways" :scrutiny:
This is what I came up with. It requires absolutely no modifications to the rifle and is 100% foolproof and will fit any M-39 and probably some other models of the Finnish Mosins. I don't see a particularly attractive way to do this on Russian Mosins.
Anyway, with like 1/2 turn past bring everything shug it would feeeeeeeel like it's reducing the downforce the barrel is exerting on the stock. It seems that would indicate the stock wants to pull down, away from the barrel. If, and I say if that is true I would think with the bedded forearm the POI can be brought down a bit for sight-in. Sorry, I shoot American, what's on top of the post .................... DIES;)
So now I need to put one of these back together so I can try it out. I got 'em both all torn apart again :rolleyes:

June 11, 2011, 09:48 PM
Rock On, Dude!!

Keep us posted :D

June 26, 2011, 07:36 PM
Well howdy folks: I finally got one of those M39's put back together and got it, bullets, range and targets all in the same place at he same time.
To briefly recap: I have completely gone through 2 "like new" M39"s. Basically blueprinting the barreled action to the stock including epoxy bedding in 3 places.
My experiement was to make the cleaning rod a tuning rod for the stock allowing the stock to be drawn up between the end cap and the threaded cleaning rod insert in the stock.
My thought was that if tension it applied to the stock between those 2 points how would affect POI.
Well, long story made really short, at 100 yrds the rod was a perfect bullseye:eek:

Ok, the rod didn't go anywhere, just mucking with you.
The result is that it didn't seem to make one tiny little bit of difference:rolleyes:
Oh, well that's cool, how ever the rifle shot spectacularly:what:
So I could be sure of shot placement I was shooting at only 50 yrds. off the bench. My 57 year old eyes don't agree with those old military iron sights.:( I did use handloaded ammo.
It was putting rounds on top of rounds. You know how, when you're shooting for groups, and how it feels when you break the trigger and you just know you threw the round high or right or whatever? And you look in the spotting scope and it's right where you thought you threw it? That's a good rifle. No headscratching:uhoh: No WUT-DA:banghead:
So the experiment was a bust but the rifle is awesome.

June 28, 2011, 02:47 PM
It was an interesting experiment though.

I've recently picked up a replacement stock for my M28 and I'm going to steal your bedding method at any rate. Are the pics in Post No. 1 showing all of the bedding spots?

June 28, 2011, 05:29 PM
Hi Cos: Yes, those 3 spots are the places that the barrel and receiver load the stock. Before you do any bedding you need to make sure the barreled action will sit in the stock completely neutral when tightened. I find the spots that need relieving using a .0015 in. feeler gauge between the stock and the receiver. To find the tight spots. I will relieve the stock where needed by the rear tang, the recoil lug and at the forearm. It just takes some patience to get a feel for what needs to be done. The recoil lug is the fulcrum. All said and done you want that barreled action, when tightened into the stock to sit in the stock without applying any left or right tension to the barrel and with only slight down pressure on the forearm. Like 2 lbs. Too much down pressure you need to shim just behind the recoil lug and not enough down pressure you need to shim under the rear tang. Then the handguard needs to be fitted so it fits tight under the retainer at the rear sight and then put just enough pad under it at the forearm to hold the barrel in the channel you just bedded.
Do that and you should see a rifle that will put the rd. where you point it. No surprises.:what:

June 28, 2011, 07:31 PM
What about using black to find the high spots? That's what I do when fitting flintlocks barrels.

June 29, 2011, 01:57 PM
Yep, I've used that as well as modeling clay. I found the feeler gauge is quick and easy. It pretty much can get where you need to go. Not always though.

June 29, 2011, 07:06 PM
Still a viable experiment, even if the results were not an improvement, it diidnt hurt it.

However, we should always strive to improve, and try try try :D I keep my eyes and mind open all the time, and such ideas and thoughts should always be shared, discussed and carried through with, 'cause Accuracy is 'where its at!!'

Keep up the good work!!

June 29, 2011, 09:44 PM
Thanks Caribou. I highly regard your encouragement:)
It was worth a try. I am kinda surprised that it didn't seem to make a difference. I did not put a lot of tension on it, but enough to see if it would do something. I got nothing :scrutiny: jeez, I've affected POI on rifles by just loosening or tightening receiver screws. I thought this would do something :rolleyes:

If you enjoyed reading about "Finnish M39 rebuild/experiment" here in archive, you'll LOVE our community. Come join today for the full version!