Finn M39 and Surplus ammo

[kBob]

OK the search function gave me a headache and as much as I hate folks that ask questions that have already been asked and answered 47 times in the lat month (M-1 Carbine for HD, Best bargin on AR15, SHTF rifles, and pistol caliber carbines spring immediatly to mind) I am about to join the annoying question club.

I understand that many of the Finn M39 rifles actually have a .308 caliber bore while "normal" Mosin Nagants can run from .310 to .312 bore diameter.

Does firing surplus ammo with .310 to .312 bullets in a .308 Finn case any damage to the Finn?

Does it cause pressure issues?

Does it allow the Finn to shoot accuratly?

If I do get a Soumi speaking rifle to go next to the Commie marshmellow cooker-44 in the safe my plan is to buy a couple of hundred boxer cases and handload for "serious shooting" if I end up with a .308 barrel, but to plink with whatever "cheap" surplus I can lay hands on if the answers to those questions ar all good.

on a related note: has anyone tried making "Mexican Match" for M39s by pulling the bullets on brass cased berdan surplus and replacing the FMJ .310+ bullet with a .308 match or hunting bullet for use in the .308 barreled Finns?

-Bob Hollingsworth

 

[Ash]

The 39 uses a 310 bore. The 28/30 uses 308 bores. Most Finns also had their chambers modified to use heavy ball, denoted "D" both in Russian and Finnish nomenclature.

The only Finns to be careful of would be the 28/30's, and of those, only those without the "D" marked chambers.

Yours will be fine. They were actually produced to be able to make full use of captured Soviet ammo, as well as domestic ammo.

Ash

 

[kBob]

Ash,

Just the guy I was looking for. Thanks.

So how well do the M39s deal with
.308 bulleted hand loads?

-Bob Hollingsworth

 

[Ash]

I don't know, but Doug Bowser who wrote "Rifles of the White Death" has several good loads he recommends, and he has several 308 loads that have worked for him, including the 168 grain Sierra HPBT Match bullets in .308 iwth IMR 4895 and 4064 powders. He has some M39 only loads in the 310-312 range. The twist is 9.5".

Ash

 

[kBob]

Ash,

Thanks again.

Senchronisity.....five y/o is out of school to day and "Ash" is currently on the living room TV babbling about Pokeman skills.

Thanks again and I am off to fix lunch.

Bob Hollingsworth

 

[Halo]

Not to hijack your thread, as this is a related tangent, but why do the Finns designate the ammo as 7.62x53R, rather than x54R? They are in fact the exact same round, aren't they?

 

[cracked butt]

Bores and grooves.

Be careful of the terminology used in order to avoid confusion.

Bore- insde barrel diameter before the grooves are cut (distance between opposing lands.

Groove- distance between 2 opposing grooves.


A rifle with a bore of .310 would have a groove diameter of about .320" after the grooves are cut .005" deep

 

[Ash]

Actually, I think it is from which side of the rim you measure from, 7.62x53R measuring from the top of the rim whereas 7.62x54R measures from the bottom. In any case, they are the same round.

Ash

 

[cracked butt]

Might hust be scandinavian curmugeons. The Finns might just want to be different from the russians. Sort of like the Norwegians and Swedes both claiming to have developed the 6.5x55

 

[kBob]

Don't have my metric SEA conversion table handy but I thought it was that the OAL is actually about 53.5mm and the Ruski round up and the Finns round down at .5

OTOH Ash's explaination would make sense

-Bob Hollingsworth

 

[kBob]

cracked butt,

thanks for the explaination. I guess I should have said barrel slug diameter, but figured Ash and you guys would know what I meant.

As to your .310 to .320 example, suppose the barrel has an odd number of grooves and the lands and grooves are of different widths.......

I am of corse just teasing and hate emoticons.

-Bob Hollingsworth

 

[_N4Z_]

To answer the question about .308dia ammo in M39's --

In my experience accuracy is just so-so. I have both well used and unissued versions, and neither shoots .308 diameter rounds well.

.311 on the other hand do far better.

If you reload look at Sierra's .303 Brit rounds. They be .311 and are quite nice.


Look to this site--> www.7.62x54r.net To find stats on various surplus rounds in that caliber.