Problems with new (to me) Mosin Nagant

G

GermanShep

New member
I picked up a 1935 vintage hex receiver m91/30 recently and tonight was my first trip to the range with it. When I got it, I completely disassembled and cleaned the bolt, scrubbed the inside of the receiver and chamber and cleaned the barrel well. I checked firing pin protrusion and headspacing with the appropriate gauges to make sure the rifle was safe to shoot. Once I got the bore cleaned up, looking down the barrel showed what appeared to be reasonably strong rifling with no pitting or damage that I could see (I am not gunsmith but it looked pretty "normal" to me).

Took it to the local indoor range since it is closest and shot the following "group" (I use the term very loosely in the case) with Brass cased, boxer primed Privi Partisan 168 gr FMJ BT.








*All shots taken at a distance of 35 yards (Longest available at this indoor range)
Point of aim was center of Target #4 for all shots except for #6 and 7 which were fired by a range officer that I called over to see if I was crazy. RO took shots #6 and 7 with a point of aim at the center of Target #5

To me it appears that the bullet is tumbling as there is "keyholing" and the holes are all over the place. A couple of things that the RO thought could be going on were:

1) inconsistently loaded ammo
2) warped barrel
3) gun doesn't like that particular bullet weight
4) fouling in barrel (none could be seen and bore was cleaned thoroughly prior to this trip)

My next step is to have a gunsmith look it over, its kinda disappointing to have these results my first time out with a mosin. I know they are not necessarily known for being MOA shooters, but I was hoping for a rifle that I could get some pie plate sized groups out to a couple hundred yards. Throwing this out to TFL experts for some ideas/guidance.

One additional note: the bolt was very sticky after firing each round. I feel like maybe I didnt get all of the cosmoline out of the receiver and as the temps increased with firing it kind of spread out onto the bolt gumming things up. A more thorough scrubbing of the receiver is in order.

Thanks for taking the time to read!
 
The bullets are not being stabilized by the rifling because the rifling is too worn to properly engage the bullet, the bore is oversize, the bullet is undersize, and/or a combination of these factors. They are tumbling and making the key hole impacts on the target. A lighter/shorter bullet in the 150g range MAY shoot better. As for the sticky bolt the ammo could be too hot or the chamber is rough or eccentric. I would get some 150g ammo and maybe the rifle will be salvageable as a shooter. Ahh the tribulations of an old MN.
 
Obviously the keyholeing is the primary issue here, but the triggers on MN's are generally poor. After a few trips to the range I found that I got used to mine and it now shoots 2-3 MOA at 100 yards with surplus ammo. Perhaps getting your hands on some surplus ammo may assist as it is ammo that was designed to be utilized in the rifle.

Don't be too concerned about the corrosive aspect, once you're finished shooting and get home just boil the kettle put a small funnel in the chamber and pour the contents of the kettle down the barrel, then clean as per usual taking care the thoroughly clean the bolt and oil properly. I've fired thousands of corrosive rounds with in my MN and it looks as good (probably better) as it did when i first got it about 4 years ago, no corrosion what so ever.
 
Loks like the muzzle is worn...

can you insert a bullet into the muzzle easily???

From the action insert a cleaning rod with bore-filling patch and slowing push towards muzzle, note where rod pushes easily.

You may have to counter bore the muzzle to remove worn section to get better accuracy.
 
I would try some surplus ammo as was already suggested. I have run into that with other surplus arms. Or: Check to see if it was rebored to 8MM by the Finns. According to their load book, this was a common practice. I did it once (8x54R).
 
Many Mosins seem to like lighter bullets better. Mine is no exception.

Make sure your muzzle crown isn't worn out by putty a loaded round in the muzzle end of the bore bullet end down. If it stops at the bullet you're good to go. If it goes to touch the brass it might be worn or counterbored. Counterbored rifles are fine, rifles with worn crowns are not. Make sure you also got any fouling out of the barrel before you shoot. I follow the practice the Swiss did by putting a coat of RIG(they didn't use RIG) on the bore and chamber if I'm not gonna shoot if for a while. Other than that I don't know. Try to sight it in using a black bullseye that you can see but isn't too big. Drift the front sight glove with a brass or aluminum punch to adjust for windage. Elevation can be fixed by adjusting the rear sight slider or putting wire coating on the front sight post and adjusting and cutting it for length. Or you can order a Smith sight. I digress.

Sorry if this was old news to you, just making sure you know!
 
Slug the bore to find out its exact size. Anything else is only better than guessing.

Theoretically the bore size for mosin is .310". The best you can do, if you hand load with commercially available bullets, is .312".

Damaged crown affects accuracy, but I don't think it would cause keyholing.

-TL
 
Theoretically the bore size for mosin is .310". The best you can do, if you hand load with commercially available bullets, is .312".
Click to expand...
"Factory fresh" groove diameters were generally a hair over 0.311". Most of the rifles being sold in the states right now have groove diameters well over .313". It is not uncommon to see them worn/corroded to .316" or even .318" (8mm!).

Generally, if .311 and .312 jacketed bullets won't shoot in a barrel, then going bigger won't make a difference.
However... there are a few companies that offer jacketed bullets in 0.313" diameter, if someone desires to test them.
Woodleigh is one of them - pretty much any of their '.32' caliber rifle bullets can be had as a .313.
 
Thanks everyone for the thoughtful replies. I thought it was a little interesting that my first shot was the only one that didn't tumble and impacted maybe an inch or so right of POI, everything else after that was all over the place. Anyway, I have a couple other follow up points and questions:

1) I really had hopes that this would be a decent shooter. I ordered the rifle from AIM Surplus and in the description it said many of the hex receiver rifles they received recently had "excellent bores" and I paid the extra $10 for the "handpick best of 5" in hopes to improve my odds of having a decent shooter. I understand that with these guns its always kind of a craps shoot though.

2) As for it being just a rough trigger, I really don't think that is the root of the problem due to the obvious tumbling that is happening. Also I don't think even I can muster up a big enough flinch to throw me off 2-3 ft at 30 yards (thats what I am going to choose to believe anyway, haha ;)

3) Im going to be trying some surplus ammo in the 147gr range soon hopefully. If that turns out to be the problem that will be an easy fix because I planned on shooting mostly surplus ammo along with some handloads if I feel like I can get worthwhile gains in accuracy doing so. I had just purchase this PPU brass cased ammo to get a small supply of brass to start loading.

4) Several people mentioned a damaged crown being a possible cause. Looking at the crown, there is not obvious damage to it or to the bore that can be seen looking down the muzzle (unloaded/no ammo in the room/bolt pulled from the action).

5) As far as slugging the bore or having the barrel recrowned, about how much should I expect to pay to have this done by a gunsmith. I really want to get this rifle shooting well, but I have to wonder how much I want to put into a gun that may not have the potential for accuracy that I hoped for.

No matter whether I can figure it out or not, I will be keeping the rifle if only for the historical value of it. I know its one of approx 17 million, but it IS a hex receiver and I really appreciate the history that it represents. Thanks everyone, keep the suggestions coming and I will be sure to report back with any progress updates! :)
 
all you need to slug your bore is take a lead bullet and using a dowel(just something hard enough but not metal)hammer the bullet through your barrel from reciever to end of barrel

then using calipers measure the diameter of the slug and thatll tell you your barrel diameter, very easy

you could prob just do it with a pulled bullet of the ammo you have now, unless your barrel is too big
 
When Mosins were even less expensive than they are now I bought a rifle & a carbine. I think they were $79 bucks just about 5 yrs ago.
I bought two 440 round tins if milsurp ammo.
Never had two rifles that awful, got shed of them pretty quickly.
Won't own a rifle at any price that won't shoot straight. Some guys have Mosins that group 2 or 3 " at 100 but that is pretty rare.
Keyholing bullets is common with the MN as bores vary wildly.
Ammo is junk if milsurp. I pulled 10 bullets that were .308 for the .311 bore.
Bullets varied 7 grains; powder varied 5 grains. Lousy WWII ammo & corrosive.
The MN is supposed to be shot WITH the bayo on it, not off it.
Why??? I don't know but it matters.
 
Slugging the bore

Would a LRN bullet from a box of factory 38 Special that i have be too large to use for slugging the bore? If I recall 38 specials are usually .355-.357 range...I reload and shoot mainly plated and jacketed bullets so I don't have many options laying around for lead bullets.

I'm still very curious as to why the first round was the only accurate one and the only one that did not tumble...or maybe I just got lucky and it passed through the paper as it was tumbling but lined up straight with the bore axis for a fraction of a second...Is there damage to that the first shot could have caused that would affect subsequent shots?
 
a 38 will be 358 diameter, you could do it with effort, lead is pretty soft

maybe hammer it down to 320 size, i dunno
 
My suggestion...as I suspect everyone else except TnTnTn may be on the wrong track...

This ain't an issue of bullet "weight" causing that much dispersion at spitting distance.

I can tell you this...
I once had some Prvi ammo that had .308 bullets instead of .311- and it looks like you've got the same problem. An undersize bullet- or an oversize bore- will exhibit the same "can't hit the broad side of a barn".

Straight from their website- you can see they do not make a .311 bullet in the 168 FMJ BT..
But they do make a .308 in that weight, the B-363.

http://www.prvipartizan.com/rifle_bullets.php

Click on .30 cal, then .303 using the "search" function.

Don't ask me why Prvi loads .308 bullets into 54R ammo. There are precious few Finns like the M28-76 with .308 bores.

Grab yourself a few rounds of cheap surplus. My bet is that you'll see a huge difference.
 
if the above poster is correct on this, that would definetly cause a huge problem, i say follow his advice

do you own a pair of calipers? they cost about 6$
 
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