New m39 b barrell

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whitey07

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This is my new to me very good too as new condition M 39B barrel . I had one about 10 to 15 years ago and was an absolute laser. I was doing my apprenticeship gotten laid off and had to pay some bills so I had to sell it . I’ve been trying to find a rifle that shoots as good ever since. I’ve gone through a couple Vkts and haven’t found one that shoots as good.
This one has a real Parts Gun Feel to it, however it cycles and ejects flawlessly. I especially like the grossly mix matched coloured hand guard.
This one has downward pressure on the muzzle and is free floated on the top of the handguard as well as full length of barrel, much like a Enfield number 4
I took it out with three different types of projectiles over 46 grains of Varget it didn’t shoot that great at 200 but it wasn’t all that bad either . and I realize this isn’t the proper load developing method .suspect it’s gotta wear in a little bit. I’m going to start at minimum and work up to maximum and .5 grain increments with one type of projectile at a time till I find one that works powders will be 4064 and 4350 IMR of course as well as varget. I’ve tried the N140 D166 route never really noticed a difference.
Target is 200 mtrs PPU 174 gr fmjbt with 46 grains varget cci lrg rifle primer Lapua brass

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There should be upward pressure at the barrel tip, not downward pressure.

Most m39’s were shimmed under the action to achieve that.

My suspicion is your rifle was tinkered on, and likely someone replaced a cracked or missing handguard with a new one. Those handguards were easy to get in NOS condition until fairly recently.

There is a good chance the original shims have been removed or installed incorrectly.

Before doing a lot more load dev, it play with action shimming until you get upward pressure and the cheap surplus rounds group 3 moa or better from a lead sled.

FWIW, from the sled, my b barrel puts Chinese surplus into about a 1.75 moa group.
 
Thank you, I worded it incorrectly. There is upward pressure at the muzzle and all the shims are in place
It actually shoots military surplus better than my hand loads as much as I hate to admit it at this point, but I’m just starting
 
Took it out with Ppu 182 FMLBT with varget IMR 40,64 and 4350 and couldn’t get better than 3 1/2 to three inches . and just for ####s and giggles. I took some card stock and put it on top of the handguard so it was completely clamped and not floated slightly at the top.so what I’m gonna do now is shim it so that I have full float on the muzzle end and try it with the hand guard off and if that works, I’m gonna relieve the front of the hand guard
That was good advice getting it to shoot with surplus before I waste my hand loads thank you
 
It’s a bit early to give up, I think. You likely just need the right load or for the stock to be set up better.

How did surplus ammo perform from a bench rest?
 
Something isn’t right with the bedding for that group size if you are aiming and shooting consistently. Are you using a fixed rest like a led sled or similar to reduce shooter inconsistency? Have you asked anyone else to print a group to compare?

No offence intended, but as people, we are also a factor.
 
Claven2 said:
Something isn’t right with the bedding for that group size if you are aiming and shooting consistently. Are you using a fixed rest like a led sled or similar to reduce shooter inconsistency? Have you asked anyone else to print a group to compare?
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Yes, my brother can take my PU Sniper, perfectly zeroed for me and capable of MOA accuracy, and shoot 4" groups with POI a foot left of my zero! Blows my mind.

Regarding this M39, my understanding is that these "B-barrels" were all M91-profile and not the heavy profile barrels of standard M39s. Perhaps they require more delicate setting up than the standard barrels? Finn-bedding (for the short, heavy barreled rifles) doesn't include contact with the wood below the "reinforce." Soviet practice (for the 91/30), on the other hand, emphasizes bedding at this point (with clearance (float) to near the forend tip. Assuming the bore is good, I would keep playing with the bedding on this rifle with surplus and commercial ammo until groups smaller than two inches are seen. In my experience, it's an unusual Mosin that can't do this with good bore and proper bedding. I have seen it commented that the Belgian barrels may not have the best steel, but my two B-barrel M91s are very accurate.

milsurpo
 
There is no appreciable difference in diameter between an m91 barrel cut down to m39 and a new made m39 barrel. The only place the diameter differs is under the rear sight base, and the Finns made 2 version of the sight base to fit both types of barrels.

Many of the VKT m39’s are also made with barrels originally intended for m91’s and you even find the odd Soviet barrel cut down to m39 spec. Despite all that, they all tend to shoot about equally well f the bedding and stock are set up correctly.
 
Claven2 said:
There is no appreciable difference in diameter between an m91 barrel cut down to m39 and a new made m39 barrel.
Click to expand...
Well, they are different and even a little bit of extra material can make a significant difference to the strength of a tube. In any case, since it's very easy to replicate Finn bedding (the shim setup was intended to make it very simple and requiring little craftsmanship), and assuming Whitey07 has made a decent effort, the explanation for poor accuracy here is most likely down to bore condition. It may not be as perfect as it appears. I have an M28-30 whose bore looks very good with a superficial exam but is actually worn enough to shoot erratically. It can put 5 in an inch and a quarter with PRVI match ammo but other commercial, surplus, and my best handloads can see groups open considerably. It also fouls much faster than a truly pristine bore.

milsurpo
 
I was shooting supported front and rear
It has eight shims by the trigger guard four in the front and then one on the left side of the recoil lug
I had an M 39B barrel that I could literally shoot sub MOA with back in the early 2000s I had to sell it and I’ve always been trying to get back to it

My research indicates all B barrel M 39 were cut down m91 barrels
I would love to find a gunsmith or somebody that really knows what they’re doing to take a look at this thing
 
I’ve never seen that many shim in an m39. Usually it’s just two or three shims at the front action screw between the receiver and stock, and maybe some at the rear tang.

Do you know the rifle’s history or if the previous owner may have adjusted things somehow?

Also, over-tightening the middle band screw can have a negative effect. It just needs to be snug enough to stay put.
 
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