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View Full Version : Russian 7.62 (.311 Bullets ) in Finnish M39(. 308 ) barrels ????



signut
02-08-2012, 09:33 PM
Have several M39's and a 91/30. Pulled bullets from a box of 78 production Russian 7.62x 54R ( from AIM )to reload with 175grain SMK's. The pulled bullets measure .311/.312. The Finnish M39's show a " 1 " or less on a set of Badger Ordanance M1 Garand erosion gauge, so barrel is right at .308.
Question: Did Finland or another country produce ammo that used the .308 projectile, or did they use ( and is it safe ) the Russian ammo in their rifles? I don't want to ruin a good barrel by using the wrong ammo. What are thoughts on this ? Thankls for your time !

El Laton Caliente
02-08-2012, 09:50 PM
NOT the expert.

A .311 bullet in a real .308 barrel is going to raise pressure. I would not do this as a "home" experiment.

l921428x
02-08-2012, 10:16 PM
I am not sure and welcome to the forum. Try also posting this in the reload forum.

Dr. Gonzo GED
02-09-2012, 01:16 AM
Slug the barrels. Seriously. Do that, man.

IIRC the M39 was the first of the Finn production rifles made for .310 - .311, but that's from memory so don't qoute me. They did up the diameter of the barrel ever so slightly from the M28 so that their troops could safely use Soviet ammo picked up on the battle field. (It's not safe to shoot Russian 7.62x54r in some of the older model Finnish Nagants)

Anyways, just slug the barrel and put any doubts to rest.

l921428x
02-09-2012, 01:52 AM
Question, what is slugging the bbl?

Schuetzenman
02-09-2012, 04:19 AM
If your Finnish M39 rifles have a captial D on the barrel they are .311" bullet compatible and are safe to shoot. I have never seen an M39 that did not have the D chamber stamp on it.

What is slugging you ask l921428x. This is a way to measure the groove depth of a rifle barrel. You take a soft lead bullet or round ball and drive it into the barrel then take a cleaning rod and tap it back out. Mic the diameter of the slug will tell you the groove diameter of the barrel. Sometimes you can also use a vernier caliper to get the bore diameter which is the diameter from rifling land top to rifling land top. In as much as a bullet is best to match the widest diameter, the groove to groove diameter is what you want to check out.

A .311 bullet in a .308 groove to groove barrel could cause dangerously high pressures unless the throating in the chamber that leads the bullet into the rifling is very long and tapered. This allows the bullet to be swagged down in diameter to fit a tighter barrel than the bullet would otherwise be suitiable for. Ruger did this with their mini-30's for a long time. They put .308 barrels on but throated them really long so the 7.62x39 bullets could get squeezed down and not pressure spike the barrel / chamber / blow the gun up.

Bluntforce
02-09-2012, 04:29 AM
Question, what is slugging the bbl?


http://www.youtube.com/watch?v=ErFaJlUVs1Y

It's even a M39 that it's being done to.

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02-09-2012, 06:20 AM
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signut
02-09-2012, 07:47 AM
If your Finnish M39 rifles have a captial D on the barrel they are .311" bullet compatible and are safe to shoot. I have never seen an M39 that did not have the D chamber stamp on it.

What is slugging you ask l921428x. This is a way to measure the groove depth of a rifle barrel. You take a soft lead bullet or round ball and drive it into the barrel then take a cleaning rod and tap it back out. Mic the diameter of the slug will tell you the groove diameter of the barrel. Sometimes you can also use a vernier caliper to get the bore diameter which is the diameter from rifling land top to rifling land top. In as much as a bullet is best to match the widest diameter, the groove to groove diameter is what you want to check out.

A .311 bullet in a .308 groove to groove barrel could cause dangerously high pressures unless the throating in the chamber that leads the bullet into the rifling is very long and tapered. This allows the bullet to be swagged down in diameter to fit a tighter barrel than the bullet would otherwise be suitiable for. Ruger did this with their mini-30's for a long time. They put .308 barrels on but throated them really long so the 7.62x39 bullets could get squeezed down and not pressure spike the barrel / chamber / blow the gun up.
The barrel is marked with a capital " D ", above the year and below the " SA ". The rifle shoots very well with the russian surplus ammo; I'm going to try the 175 SMK's and maybe some 155 Lapua Scenar bullets to see if it will group even tighter.
It just seems strange that the Finns would fit that tight a barrel on a rifle knowing that there was millions of rounds of russian ammo available. May do a Cerrosafe casting of chamber and throat to see what the leade angle and throat looks like.
Never had any Mosin's before these . Interesting history behind rifle.

Dr. Gonzo GED
02-09-2012, 08:05 AM
[B]The barrel is marked with a capital " D ", above the year and below the " SA ".Never had any Mosin's before these . Interesting history behind rifle.
M39 is the best of them IMHO. What color is the Barrel? Can you post pics of the Arsenal stamping on the receiver?

Schuetzenman
02-09-2012, 06:41 PM
The barrel is marked with a capital " D ", above the year and below the " SA ". The rifle shoots very well with the russian surplus ammo; I'm going to try the 175 SMK's and maybe some 155 Lapua Scenar bullets to see if it will group even tighter.
It just seems strange that the Finns would fit that tight a barrel on a rifle knowing that there was millions of rounds of russian ammo available. May do a Cerrosafe casting of chamber and throat to see what the leade angle and throat looks like.
Never had any Mosin's before these . Interesting history behind rifle.

You have to understand that the Finns hated the Russians. Russia was an occupier of Finland and when the Russian Revolution broke out the Czar pulled most of his troops out of the Finnish bases leaving behind token levels of manning. The Finns figured this out, attacked and kicked the Russians out. Tens of thousands of weapons were left behind and captured. The Finns then went about restocking, rebarreling and otherwise trying to change up and improve the Mosin 91's left behind. The 25, 26, 27 models if i recall were based on the .308 barrel dimensions. But as mentioned they figured out it was preventing them from using battle field pickup ammo. I thin the 28 and finally the 39 were fielded with barrels set up for the .311 bullet.

I have heard of M39 weapons called Sneaks that had .308 dimensioned barrels on them, these are quite rare. Your typical M39 with the D is norm and you can shoot .311 ammo in it all day long. A photo of your rifles would be nice. Always good to see another Finnish m39.

signut
02-09-2012, 09:55 PM
You have to understand that the Finns hated the Russians. Russia was an occupier of Finland and when the Russian Revolution broke out the Czar pulled most of his troops out of the Finnish bases leaving behind token levels of manning. The Finns figured this out, attacked and kicked the Russians out. Tens of thousands of weapons were left behind and captured. The Finns then went about restocking, rebarreling and otherwise trying to change up and improve the Mosin 91's left behind. The 25, 26, 27 models if i recall were based on the .308 barrel dimensions. But as mentioned they figured out it was preventing them from using battle field pickup ammo. I thin the 28 and finally the 39 were fielded with barrels set up for the .311 bullet.

I have heard of M39 weapons called Sneaks that had .308 dimensioned barrels on them, these are quite rare. Your typical M39 with the D is norm and you can shoot .311 ammo in it all day long. A photo of your rifles would be nice. Always good to see another Finnish m39.
I will take some pics of the 3 Finnish M39's tomorrow; if I email them to someone here can they post them as I am not familiar with this feature. I did notice that one of the 39's has the " D " and the other two ( both Sako ) have no marking
other than " SA " and year. I am going to slug all three barrels just to check and be safe. Later!

Rainman
02-10-2012, 10:36 PM
Both of mine have D barrels and shoot the Russki and Bulgy light ball fine. They really shine with the Bulgy heavy ball. It's getting hard to find now, so I bought a case of PRVI 182gr FMj and am keeping the brass, and marking it for the specific rifles it was fireformed in. Hoping to develop a cast load that'll both shoot well and dispatch the TexPigs we have running around the farm