Finnish Mosin M91 Question

[chooks9]

I picked up a pretty nice M91 Finnish Mosin with a Tikka barrel at the Timonium Gun Show. I just read something that many M91s were barreled for 7.62x53R not the standard 7.62x54R. I know that in the grand scheme of guns, 1mm is a huge deal. However, this story contended that the x54R ammo is safe to shoot in these guns. Is this correct?

 

[Dave91]

I would like to know the answer to this as well. I know some Finnish rifles can shoot both because there was so much Russian ammunition on hand. I'm not sure about the m91's.

 

[ken792]

I believe a "D" marking on the chamber indicates that it can use captured Russian ammo.

 

[Sirex]

My M91s all shoot regular 54r fine, but none are Tikka barrels.

 

[Dave91]

For what it's worth, Wikipedia says shooting 54 through a 53 bore can be dangerous and could mess up the rifling.

 

[jodavk]

I believe that the D stamp on a Finn'd M91 means that the chamber was very slightly reamed to allow for the D166 heavy ball (203 grains maybe); slightly longer bullet. I have fired plenty of milsurp spam can ammo in my D stamped M91s with no problems.

 

[Melnic]

My 41 VKT M39 has the D on it and I'm shooting nothing but surplus through it.

Yours did not have an import stamp with the caliber on it?

 

[chooks9]

I have no A, B, C, or D stamp on my barrel. It just has the 'T' in the upside-down triangle, SA military markings, and a 1942 barrel mfg. date. I would only be shooting 148gr x54R ammo from spam cans, so i'm not too concerned...but I still don't want a Mosin bolt permanently attached to my face...

 

[chooks9]

My 41 VKT M39 has the D on it and I'm shooting nothing but surplus through it.

Yours did not have an import stamp with the caliber on it?

It does have an extremely faint CAI stamp on the barrel that says 7.62x54R. I'm not the most trusting of CAI...I have owned some stuff they sold that I wouldn't sell to an enemy.

 

[Boom Boom]

For what it's worth, Wikipedia says shooting 54 through a 53 bore can be dangerous and could mess up the rifling.

A website on the internet shouldn't be needed to figure out that shooting a high-powered rifle bullet through a smaller-diameter bore is dangerous to one's existence.

 

[Sirex]

I think the difference is the case is 1mm shorter on the 53r, or they measured differently. The Finns used .308 bullets instead of .310-.312, so you may have higher pressure and more rifling wear and they were longer too. That said, I have never heard of an issue shooting 54r thru one. I would suggest slugging the barrel.

 

[Sirex]

What year is the barrel? May be ok, just not marked. Info;
http://www.mosinnagant.net/finland/finnfaq.asp

http://62x54r.net/MosinID/MosinM91F.htm

Since it's unmarked and a later date barrel, I would speculate it's okay to use surplus 54r. Still would slug it to be safe.

 

[monsternav]

I believe that the D stamp on a Finn'd M91 means that the chamber was very slightly reamed to allow for the D166 heavy ball (203 grains maybe); slightly longer bullet. I have fired plenty of milsurp spam can ammo in my D stamped M91s with no problems.

It's not the chamber, it's the bore diameter. If it's marked with an "A" or a "D" it can shoot 310/311 bullets (what the Russians used). "B" or "C", I would not do it. Since yours is not marked I would slug it (no matter when you think the rifle was put together).

"B" bore diameter marking should not be confused with the "B" makers mark for the barrel. How's that for you?

Collecting and shooting old rifles is always interesting.

Take some pictures and post them. There are often a lot of markings on Finn rifles. Maybe we can help sort it out.

 

[iH8DemLibz]

The 53 is .03937 (1mm) shorter in case length compared to a 54.

Has nothing to do with the bore diameter.

A lot of those old .308 bores are so worn that shooting a .310/.311 may help accuracy.

 

[monsternav]

Here, make your own decision. Downloaded from CIP. Dimensional differences are very small, but they are there. It seems to be accepted that "D" marked barrels are good to go with actual Russian ammo. Anything else, it's up to you.

 

[chooks9]

What year is the barrel? May be ok, just not marked. Info;
http://www.mosinnagant.net/finland/finnfaq.asp

http://62x54r.net/MosinID/MosinM91F.htm

Since it's unmarked and a later date barrel, I would speculate it's okay to use surplus 54r. Still would slug it to be safe.

The barrel is dated 1942. Thanks for the links!