Help with an M39 please

[Austin26]

I'm somewhat versed in 91/30s and M39s as far as markings but I'm no expert. I just bought a 1944 M39 Sako of the Finnish Army and wanted to see what else y'all's experience and knowledge base could tell me about it.

https://www.gunbroker.com/item/922538253

What's the wood circle on the stock? Was it a repair job perhaps? This rifle is to be a shooter. What are considered average groups at 100m/yd with good to match ammo? I have some S&B 180 grain FMJ brass ammo and will be getting some PPU 182 gr match ammo when I can finally find some. I have pretty good eyesight and am a decent shot as I have qual'd well with irons many times. My skills have regressed as I don't shoot as often as I used to. I only mention that because obviously most firearms are more accurate than their owners and y'all guessing what groups to expect hinges on my skill level.

Here is a link to pictures. Thanks in advance. I'm excited! Boy did I get into military surplus too late. Ugh. I will have paid $940 total to get this.

Edit: the scrubbed marking looks to be the Russian eagle or bird but I could be wrong. At first I thought it could have been the tree. Here are two pictures of them on different rifles to show what I mean.

I'm not good at posting things apparently. I don't know if my pictures are working.

E0A44208-938C-4EF2-94EA-3D7723745BDD.jpeg

1EF718E8-2B48-43D4-B110-A7B0E5F1E76F.jpeg

[qz2026]

This was once, not long ago a $350 rifle before Classic got a hold of them. This was probably one of Pat Burns guns from days past. I can't imagine getting into the hobby now. The prices have just gone crazy with no end in sight. Taxes and shipping are taking their tolls anymore on GunBroker. If you're going to desire a Mosin, this is the one to get but holy cow...

The circle on the butt stock is a dowel repair. Nothing to worry about. These were quite common to fix gouges or other minor damage. And the Finns did a masterful job. This is a very nice SAKO. They don't get any better than this one. The Finns tended to scrub the Eagles off some of the receivers but that was inconsistent.

You shooting will improve after you begin shooting again.. I had the same problem. It had been 40 year since I had fired a rifle when I began the hobby. Zero it at 50 yards and then make any needed sight adjustments. This should shoot two inch groups at 100 yards if you can see the bull that far away. I can't anymore . The M-39 was arguably the most accurate rifle of WWII and certainly the most accurate Mosin ever made.

Be sure that you thoroughly clean the gun of any grease paying particular attention to the chamber.

[Mangrove]

What are considered average groups at 100m/yd with good to match ammo? I have some S&B 180 grain FMJ brass ammo and will be getting some PPU 182 gr match ammo when I can finally find some.

According to one factory acceptance test, the average result for a 1943 m/39 (n=128) with D-166 round was 2 MOA at 300 metres (8 best hits out of 10) or 0.9 MOA at 300 metres (the best 4 hits).

[qz2026]

Problem is that you will not be shooting D-166 rounds unless you load them up yourself. I believe that D-166 is a 7.62x53r cartridge too. Difficult brass to come by even during the good times. I suppose you could trim the length down to 53mm. But, the projectile is .309 for the 53r and .312 for the standard 54r. D-166 is not available for purchase unless you could score some from Finland or someone who has some D-166 surplus hanging around that would be willing to part with it.

[Austin26]

The circle on the butt stock is a dowel repair. Nothing to worry about. These were quite common to fix gouges or other minor damage. And the Finns did a masterful job. This is a very nice SAKO. They don't get any better than this one. The Finns tended to scrub the Eagles off some of the receivers but that was inconsistent.

Thanks for your helpful response.

I just watched a video by Ian of Forgotten Weapons on the Finnish Mosins and he showed a circular mark in a butt stock that was once an Army unit "medallion" of sorts, identifying that the rifle belonged to whatever Army brigade or however they categorize things over there. But that after a while, the Finns realized they were giving the Russians free intel by identifying their rifles should they be captured or killed, and they stopped doing so and removed the little circular unit IDs. Could this be that or does this just look like a dowel repair job?

When you say "this" Sako is a nice rifle, were you meaning the one I bought on Gun Broker via the link? To be clear, the attached images of two receivers were to just show what my M39's scrubbed marking may have looked like previously. I'd very much like an opinion of yours and this board's on mine. It was $780 plus taxes and shipping and FFL transfer, so $940 total. And yes unfortunately I too remember when 91/30s were 130$ and then 200$ and the "rare" ones double that. Oh well. Glad my life is stable and I can have some fun.

If it is indeed a Russian Eagle, that sounds Imperial Russia and not Soviet Era... So this receiver was made after 1891 and before 1917-1918 when the Bolshevik revolution occurred? Then re-arsenaled in Sako in 1944 as an Model 39 for the Army? And could have been an M24, 27, 28/30 in the mean time?

Be sure that you thoroughly clean the gun of any grease paying particular attention to the chamber.

If there is some cosmoline left on the metal is there any harm to disassemble it completely and boil the metal only? I had completely disassembled a different 91/30 and boiled and cleaned to remov all traces of cosmo, then oiled With CLP gun oil and reassembled. Looked really nice without changing the patina or wear and didn't damage anything obviously. Is that okay to do to this one?

I read one can't remove cosmoline from wood without refinishing it. Is this true? If so I'll just deal with it. I would like to boil the cosmoline off though. There was so, so much crap on my last one. The goofball had fired it without removing the cosmo so it gummed up. Luckily it didn't look like he used corrosive ammo as the bore cleaned up quite nice though it took four products and hours to eat through probably 70-100 years of fouling.

According to one factory acceptance test, the average result for a 1943 m/39 (n=128) with D-166 round was 2 MOA at 300 metres (8 best hits out of 10) or 0.9 MOA at 300 metres (the best 4 hits).

I'm familiar with the fact that the D-166 was the Finnish standard load though I don't know how it differs from any other 7.62x54R.

I don't understand what you mean by 2 MOA @ 300m OR 0.9 MOA @ 300... Do you mean that of 10 hits, eight should be within 2 MOA and that four are within 0.9 MOA? If so, at 300m this is roughly six inches and 2.7 inches respectively, correct?

Unless I'm not thinking of something that's sub MOA @ 100?? That's bananas accurate. Either way, I'd love it if mine were so. I wonder what y'all's actual average groups are.

[millman]

The mark on the receiver is/was a Russian eagle.

[Mangrove]

I just watched a video by Ian of Forgotten Weapons on the Finnish Mosins and he showed a circular mark in a butt stock that was once an Army unit "medallion" of sorts, identifying that the rifle belonged to whatever Army brigade or however they categorize things over there. But that after a while, the Finns realized they were giving the Russians free intel by identifying their rifles should they be captured or killed, and they stopped doing so and removed the little circular unit IDs. Could this be that or does this just look like a dowel repair job?

Finnish Defence Forces used unit discs both pre and post-war. The m/39 you linked never had a unit disc since they would have been placed on the right side of the buttstock.

If it is indeed a Russian Eagle, that sounds Imperial Russia and not Soviet Era... So this receiver was made after 1891 and before 1917-1918 when the Bolshevik revolution occurred? Then re-arsenaled in Sako in 1944 as an Model 39 for the Army? And could have been an M24, 27, 28/30 in the mean time?

Vast majority of the m/39 were made using receivers from m/91 and m/91-30. It would have been very unsual to use a receiver from older Finnish-made rifle since most of them would have been only 10-15 years old during the WWII.

I read one can't remove cosmoline from wood without refinishing it. Is this true? If so I'll just deal with it. I would like to boil the cosmoline off though.

Finnish Defence Forces nor the Civil Guard used cosmoline. Finnish military districts and depots used Shell Ensis Oil 152 at least since the mid-1960s to preserve the rifles. Some also used "English cannon crease" (englantilainen tykkirasva) or Anti-Corrol oil. Some units immersed the whole rifle to the oil, some poured it down the barrel. Shell recommends wiping it down or using alkaline solution. There is no need to remove the oil from the inside of the rifle.

I'm familiar with the fact that the D-166 was the Finnish standard load though I don't know how it differs from any other 7.62x54R.

I don't understand what you mean by 2 MOA @ 300m OR 0.9 MOA @ 300... Do you mean that of 10 hits, eight should be within 2 MOA and that four are within 0.9 MOA? If so, at 300m this is roughly six inches and 2.7 inches respectively, correct?

Unless I'm not thinking of something that's sub MOA @ 100?? That's bananas accurate. Either way, I'd love it if mine were so. I wonder what y'all's actual average groups are.

Here's link to 1937 D-166 technical drawing. The modern one produced by Lapua is slighly different. Here's link to 1936 Finnish Defence Forces ballistics charts for D-166 (2.8 grams / 43 grain of VRT, Vihtavuori, powder).

That's correct. Out of 10 rounds, eight were within 2 MOA and 4 were within 0.9 MOA. This roughly translates to that half of the rounds were within 1 MOA. 0.9 MOA @ 300 metres is roughly 3.1 inches and 2 MOA @ 300 metres is 6.9 inches.

The accuracy requirements for the first batch of Civil Guard m/39 rifles ordered in July 1940 were circa 1.2 and 2.3 MOA at 300 meters (see translation below). However, the accuracy of most rifles was much greater than the requirement. During the WWII, the number of rounds shot during testing was reduced from 20 to 10 (the two worst rounds were always disqualified).

c) Precision test.
The same rifle barrels used in the high pressure test fire, shall also be used for precision test firing from a distance of 300 meters (20 cartridges). Either hand or machine loaded Civil Guard cartridges shall be used in the test firing.

To be accepted, each barrel must achieve the following result when fired from a machine rest or by a good shooter from a rest:
- The radius of the best 18 shots = 100 mm
- The radius of the best 9 shots = 50 mm
The circles formed by the radii have the same centre.

The test firing results for M/28-30 produced in 1940 (n=62) were 2.3 MOA (8 rounds out of 10) and 1.1 MOA (4 rounds out of 10) at 300 metres. The post-war tests with S-283/4 ammunition resulted in a bit better accuracy over the D-166.

7.62 TKIV 85, which is based on m/39, is expected to have groups less than 1 MOA at 0-300 metres and less than 1.5 MOA at 300-600 metres. D-166 loses a lot of momentum after 500-600 metres and its accuracy is at best around 3 MOA at 750 metres.

[Austin26]

Finnish Defence Forces used unit discs both pre and post-war. The m/39 you linked never had a unit disc since they would have been placed on the right side of the buttstock.

Got it. Good to know.

Vast majority of the m/39 were made using receivers from m/91 and m/91-30. It would have been very unsual to use a receiver from older Finnish-made rifle since most of them would have been only 10-15 years old during the WWII.

That's interesting. I was under the impression that as they upgraded their rifles from the M24 up to the M39, they'd upgrade the specs when a rifle came in to be fixed for something. As in, say an M27 came in with a cracked stock in 1942, it may be brought up to M39 specs before being returned to service.

Finnish Defence Forces nor the Civil Guard used cosmoline. Finnish military districts and depots used Shell Ensis Oil 152 at least since the mid-1960s to preserve the rifles. Some also used "English cannon crease" (englantilainen tykkirasva) or Anti-Corrol oil. Some units immersed the whole rifle to the oil, some poured it down the barrel. Shell recommends wiping it down or using alkaline solution. There is no need to remove the oil from the inside of the rifle.

When you mean inside the rifle do you mean the bore or disassembling all metal parts to clean thoroughly? Is there anything wrong with doing so? I don't wish to alter it's look or function in any way but I do wish to clean it without doing harm. What's the best way to accomplish this?

Here's link to 1937 D-166 technical drawing. The modern one produced by Lapua is slighly different. Here's link to 1936 Finnish Defence Forces ballistics charts for D-166 (2.8 grams / 43 grain of VRT, Vihtavuori, powder).

That's correct. Out of 10 rounds, eight were within 2 MOA and 4 were within 0.9 MOA. This roughly translates to that half of the rounds were within 1 MOA. 0.9 MOA @ 300 metres is roughly 3.1 inches and 2 MOA @ 300 metres is 6.9 inches.

The accuracy requirements for the first batch of Civil Guard m/39 rifles ordered in July 1940 were circa 1.2 and 2.3 MOA at 300 meters (see translation below). However, the accuracy of most rifles was much greater than the requirement. During the WWII, the number of rounds shot during testing was reduced from 20 to 10 (the two worst rounds were always disqualified).

c) Precision test.
The same rifle barrels used in the high pressure test fire, shall also be used for precision test firing from a distance of 300 meters (20 cartridges). Either hand or machine loaded Civil Guard cartridges shall be used in the test firing.

To be accepted, each barrel must achieve the following result when fired from a machine rest or by a good shooter from a rest:
- The radius of the best 18 shots = 100 mm
- The radius of the best 9 shots = 50 mm
The circles formed by the radii have the same centre.

The test firing results for M/28-30 produced in 1940 (n=62) were 2.3 MOA (8 rounds out of 10) and 1.1 MOA (4 rounds out of 10) at 300 metres. The post-war tests with S-283/4 ammunition resulted in a bit better accuracy over the D-166.

7.62 TKIV 85, which is based on m/39, is expected to have groups less than 1 MOA at 0-300 metres and less than 1.5 MOA at 300-600 metres. D-166 loses a lot of momentum after 500-600 metres and its accuracy is at best around 3 MOA at 750 metres.
[/quote]

I will have to read this more when I have time. Thank you!

[qz2026]

Good response. Saved me a ton of time Bottom line is that this rifle will shoot far better than you can or most any other WWII Milsurp can. This is the reason they are so sought after. It doesn't hurt that they are flat out beautiful rifles either.

Removing grease from the stock. Just wipe it off, You can use a heat gun to help or just leave it out in the sun and wipe it down occasionally. If it bleeds at the range, take a rag with you and wipe it off with. But, really, if you wipe it down well inside and out and remove the grease from the barrel and internals, you shouldn't have much of a problem. I'll just continue to wipe it down until no grease comes off on the rag (or paper towel) any longer. Some say to use mineral spirts. This works ok and will not harm the finish. Anymore, I think the armstrong method is the best. If the inside of the stock or rifle for that matter has heavy build up, remove that first with something like a nylon pic to get as much grease off as possible before you start wiping. You really don't want to risk doing anything that would damage the finishes on these guns. And really, your rifle doesn't look to have a bunch of or any grease on the stock. Looks like the previous owner did all the work.

And in anticipation... Once the grease (if any) is gone, there is no need to apply anything on the stock. It will be fine as is. Leave it as it is.

[Mangrove]

That's interesting. I was under the impression that as they upgraded their rifles from the M24 up to the M39, they'd upgrade the specs when a rifle came in to be fixed for something. As in, say an M27 came in with a cracked stock in 1942, it may be brought up to M39 specs before being returned to service.

First of all, it is good to distinguish Finnish Defence Forces property from that of the CIvil Guard. Both were under the Ministry of Defence of Finland and received funds from the State of Finland. However, until November 1944, Finnish Defence Forces did not have the right to do more than basic repairs to the Civil Guard rifles (namely m/24, m/28 and m/28-30).

Secondly, although there had been Finnish Defence Forces and Civil Guard upgrade programs going on since the early 1920s, vast majority of operational rifles in both organisations were pre-WWII m/91 rifles. Instead of upgrading good enough 1920s and 1930s rifles, it was decided such rifles were only repaired when necessary and m/91 were upgraded to m/39 when enough factory and depot resources were available.

When you mean inside the rifle do you mean the bore or disassembling all metal parts to clean thoroughly? Is there anything wrong with doing so? I don't wish to alter it's look or function in any way but I do wish to clean it without doing harm. What's the best way to accomplish this?

The Shell Ensis Oil instructional leaflet I have seen only mentions briefly that "there is no need to remove the protective film". However, I would think the Finnish Defence Forces would have at least cleaned the bore if they would have issued the m/39 rifle in the 1960s or 1970s. The only Finnish Defence Forces instruction I have seen telling to clean every single moving part is when the rifle is issued during very cold temperatures (down to -40 degrees centigrade or fahrenheit).

[qz2026]

Your stock repair was done when the stock was made I suspect.

I referred to cleaning the inside of the stock, i.e., removing the grease. Something tells me that we are discussing two different things in this thread.

Austin was referring to the internals of the rifle. I don't know anything about what the Shell Ensis Oils Instructional leaflet says, Likely a process/procedure done back in the day. Regardless, if your internals and/or the rifle itself has a grease coating, it should and IMHO must be removed. Very hot water and dawn dish soap or other mild grease cutter. Remove the rifle from the stock to protect the stock. Afterwards thoroughly dry and lightly oil with the preservative of your choice. Reassemble the rifle and place it back in the stock.

M-91 "upgraded to M-39? Both and all Finn Mosins shared Russian parts, the receiver, bolt, butt plate, magazine and many if not all internals, although the Finns did manufacture some triggers. Perhaps "upgraded" is the incorrect word to use. More aptly, production of the M-91 ceased as did all interim rifles (M24, M27, M28, M28/30) and the M-39 (an entirely new rifle) was instituted as the primary Finnish small arm to be manufactured. That doesn't mean that refurbishments did not continue.

[Austin26]

@Mangrove and @qz2026. Thank you for your reply. Yes, I was talking about just the metal parts really as QZ said.

That's interesting that they just you using old M91s to create new and better rifles instead of taking good enough predecessors to the M39 and rebuilding them and it makes sense. I knew they had around 190,000 M91s to start once Finland became independent and acquired more along the way but I didn't realize they had such a surplus.

I'd write more but I'm at work. Will reread your responses later. Thank you.

[SA1911a1]

Holy Moly! Is that what M-39s go for now days?

[Austin26]

Holy Moly! Is that what M-39s go for now days?

Unfortunately a typical 91/30 goes for $400 and the last few M39s I've bid on on Gun Broker went for $1,250, $1,050ish, $1,000. Mine was $780 before FFL and taxes and shipping. I've picked a poor time to get back into Mosins. If you have any you don't really want anymore, from now on they'll only increase in value and one could tell their wife "see, I've made a great investment!" and it be true ha.

[Austin26]

Good response. Saved me a ton of time Bottom line is that this rifle will shoot far better than you can or most any other WWII Milsurp can. This is the reason they are so sought after. It doesn't hurt that they are flat out beautiful rifles either.

Removing grease from the stock. Just wipe it off, You can use a heat gun to help or just leave it out in the sun and wipe it down occasionally. If it bleeds at the range, take a rag with you and wipe it off with. But, really, if you wipe it down well inside and out and remove the grease from the barrel and internals, you shouldn't have much of a problem. I'll just continue to wipe it down until no grease comes off on the rag (or paper towel) any longer. Some say to use mineral spirts. This works ok and will not harm the finish. Anymore, I think the armstrong method is the best. If the inside of the stock or rifle for that matter has heavy build up, remove that first with something like a nylon pic to get as much grease off as possible before you start wiping. You really don't want to risk doing anything that would damage the finishes on these guns. And really, your rifle doesn't look to have a bunch of or any grease on the stock. Looks like the previous owner did all the work.

And in anticipation... Once the grease (if any) is gone, there is no need to apply anything on the stock. It will be fine as is. Leave it as it is.

Thank you. I do wonder why mine is bright / shiny and kind of orangey brown versus how many are a more muted dirt brown color. In fact I thought that could be the reason I was able to buy it for less than others I've been bidding on and losing on. I thought the stock had been refinished someone in the last 50 years. I admit I like the dull light brown look for most M39s better than mine.

So just leave it in the sun this summer and gentle wipe any excess off. Interesting. I can't screw that up.

Edit: ah, I think I have my answer. It has a squared spliced stock indicating a refurbished post WWII. Oh well. I guess it doesn't matter though older would have been nice.

[Austin26]

According to one factory acceptance test, the average result for a 1943 m/39 (n=128) with D-166 round was 2 MOA at 300 metres (8 best hits out of 10) or 0.9 MOA at 300 metres (the best 4 hits).

I took my '43 and '44 Sako M39s to the range today. I'm having issues with my '44 but the '43 shoots in line with their testing tolerances. I had seven of 10 within 4" at 300 yds (274 m). S&B 174 gr match ammo. There were three others that were vertically strung but with a gusting near full value wind and mirage, I'm content with how it performed.

Oh, and was Finnish doctrine to line the front sight on the bottom of the target? I used a couple different types of ammo today and all were way high. I ended up aiming what was about 8" low on the target at 300 yards to hit seven inches high with the sights at 150 m! They didn't build the M39 to be zeroed with a bayonet did they? Other than that I'm out of ideas on why it's so high. Perhaps I need a taller front sight post. My '44 has a 78 on the barrel next to it which I read was 7.8mm. EDIT #2. The front sight is marked needing 7.8mm and the front sight post is also marked 7.8mm , it was just hard to read. Still looking for a solution please!

This trigger is the worst trigger that I've ever used. Even my 91/30 is borderline good. Does anyone here have someone they'd trust with a Mosin trigger job? I'd prefer not to have to buy a belt sander and experiment but I will if I need to. There's one mile of travel that is compressing Spongebob SquarePants inside the receiver I'm assuming, then a modest wall, and then a break that comes at some point after that though it changes every once in a while. The trigger and sear don't visually look f'd, but something is causing this. I think I'll start by boiling the bolt pieces like I do on Russian stuff to remove cosmoline, though this rifle is fairly clean in the trigger and bolt.

[Mangrove]

Oh, and was Finnish doctrine to line the front sight on the bottom of the target? I used a couple different types of ammo today and all were way high. I ended up aiming what was about 8" low on the target at 300 yards to hit seven inches high with the sights at 150 m! They didn't build the M39 to be zeroed with a bayonet did they?

M/39 rifles were zeroed without a bayonet usually at 150 metres (c. 165 yards) with 200 gr D-166 ammunition flying at 690-710 meters per second (c. 2200-2300 feet per second). In fact, Finnish Defence Forces stopped issuing bayonets to rifles during the autumn of 1943. If you're using lighter ammunition, you should compensate this by having a taller front sight.

[Austin26]

Oh, and was Finnish doctrine to line the front sight on the bottom of the target? I used a couple different types of ammo today and all were way high. I ended up aiming what was about 8" low on the target at 300 yards to hit seven inches high with the sights at 150 m! They didn't build the M39 to be zeroed with a bayonet did they?

M/39 rifles were zeroed without a bayonet usually at 150 metres (c. 165 yards) with 200 gr D-166 ammunition flying at 690-710 meters per second (c. 2200-2300 feet per second). In fact, Finnish Defence Forces stopped issuing bayonets to rifles during the autumn of 1943. If you're using lighter ammunition, you should compensate this by having a taller front sight.

Thank you. How would one acquire a (much) taller front sight post? I don't see a difference of 28 grains being enough to drop an additional approximate 20" at 300 yards. But regardless if I had a taller front sight post it would fix this problem.

[Mangrove]

How would one acquire a (much) taller front sight post? I don't see a difference of 28 grains being enough to drop an additional approximate 20" at 300 yards. But regardless if I had a taller front sight post it would fix this problem.

For precise calculations, I think you should first try shooting a few shots at 50, 100, 150 or 150 metres using the corresponding sight. You may then use the table below to estimate how taller the front sight should be.

From Finnish Defence Forces booklet "Ohjeita ampumakouluttajille kivääriperusammuntakoulutusta varten" (1949), pages 12, 13 and 14. Translation from Finnish to English by me:

"The distance between the notch and the post in the m/39 rifle is such that if the notch is elevated by 0.1 mm, the mean point of impact will rise by 50 mm or one circle in the [international] target (not quite but effectively). The following table shows the elevations in the sight notch as the slide moves notch by notch from the basic position up to 600 metres.
[...]
The table contains calculated mean point of impacts corresponding to each elevation at the target located at a distance of 50, 100, 150 and 300 metres. The table also shows the tolerances allowed in the manufacture of the sight. This will give an idea of how carefully and accurately the sights are made.

Let's assume that the shooter has fired 3 test shots [...] to a target at a distance of 150 metres. The sight has been set to position 2.6 (i.e. in the 6th notch ahove the 200 metres position). Once the mean point of impact has been determined, it is found to be 1½ circles (75 mm) too high. From the table, we see that the sight must be set to position 2.2 (i.e. the second notch ahove the 2) in order for the mean point of impact to descend to the correct height. [...]"

Tähtäimen asento = Sight position
Hahlon nousu = Sight notch rise
Sallittu valmistustoleranssi mm = Allowed manufacturing tolerance in mm
Tähtäimen siirron aiheuttama iskemäkeskipisteen nousu mm = Rise in mean point of impact (in mm) caused by moving the sight

[millman]

Good info Mangrove . Thanks.