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Garbage Rod Accuracy

Anhur

Plastic
Joined
Nov 11, 2017
Hey all, I have an old Mosin Nagant 91/30 rifle that started life in 1943 in Izhevsk Russia. Being a midwar non-Tula round receiver with nothing special to be spared for I hacked it up some years back. The problem I had is it would never shoot right. It has always sent bullets downrange in 10-12" random patterns. I probably incorrectly assumed that the old wooden stock and full length hand-guard was to blame and I fitted it with one of those black plastic ninja tacticool stocks made by Archangel. To be fair I was a bit younger and the stock is kinda nifty. This obviously didn't fix my issues so I went further and cut the barrel down to 18" and threaded it for a muzzle brake. I also went ahead and trued the end and cut a really nice 11 degree target crown in the barrel. This also did nothing. I had installed a cheap Nikon scope originally with an ATI mount, thinking that this may be the issue I bedded the scope mount and installed a SWFA 10X40. I could now see my crap shooting better, but it did not improve my results. I then went ahead and installed a Timney drop-in trigger and while I had the stock off I milled out all the area in the stock ahead of the receiver and checked it for clearance. I also took the receiver and trued the back of the recoil lug on my mill and bedded it into the stock with Marine Tex. I then bore-scoped the barrel and slugged it to check sizing. It came back right at 0.313" I also spent some time checking the bore for straightness. It seems okay with no obvious indications of a defect. I have tried different ammo from the spam can surplus to the PPU blue box stuff and even some hand-loads with 0.311" SMKs. I am bench shooting it from a concrete table at 100 yards and literally it is difficult to keep it on paper. I would say the average group size is 10" or so and it is not centered ever. I don't pretend to be the worlds best shooter, but I think I'm better than that. My Savage 10 FCP-SR in .308 is a 1/4 minute gun at the same range on the same table using the same bipod and bag setup. I feel that this thing is starting to challenge my intelligence now. For it to be that far out it seems to me that the problem must be huge and probably obvious. I came here fishing for suggestions, so all comments are welcome even if they seek to understand why I'm wasting my time on this thing. It's all principal now I refuse to let it go until I have a valid diagnosis of the issue even if it results in "wall-hanging" this thing. Sorry for the long post and thanks in advance.
 
I would suggest trying to shoot through paper at short distances 5 yards or so to see if the bullets are going sideways when leaving the barrel. Then check to see if the forcing cone is buggered up or if the gap before the bullet hits the rifling is too great. Also, have you tried out some go and no-go gauges for checking chamber length and headspace? Oh, and check the lands where the bullet first comes in to contact with them. Make sure it's a smooth entrance and brass isn't being shaved off or buggered up.

That's all I've got. ;)

JMHO

-Ron
 
I would suggest trying to shoot through paper at short distances 5 yards or so to see if the bullets are going sideways when leaving the barrel. Then check to see if the forcing cone is buggered up or if the gap before the bullet hits the rifling is too great. Also, have you tried out some go and no-go gauges for checking chamber length and headspace? Oh, and check the lands where the bullet first comes in to contact with them. Make sure it's a smooth entrance and brass isn't being shaved off or buggered up.

That's all I've got. ;)

JMHO

-Ron

I will try some at a closer distance. My next trip to the range I am going to hand-load some different powder charges. Maybe I'm just way off the node??? I did check the headspace when I got it, and it was in spec. I also did a chamber cast at one point and inspected the throat and it seemed okay. It looked like a bit of excessive freebore, but from my understanding these old rifles had quite a lot of jump even new. I will probably measure the freebore now as you have me wondering. I highly doubt that Hornady has a modified case gauge for one of these so I will probably have to make one. I was also looking at the bolt. It seems as though one of the lugs is only contacting 1/2 way. I don't know if that would be enough to cause this big of an issue.
 
I would take it out of the stock and bench clamp it then run a clip through..If it doesn't hold a couple inches at 100 yards I would chuck it..
Sounds like you did plenty of work and I would like to see a photo. Never liked the long barrel, the safety and rimmed ctg, so never owned/shot one.

Oh! QT: [I had the stock off I milled out all the area in the stock ahead of the receiver and checked it for clearance.] looks like you covered that..so my suggested bench test covered.

Still you need a rainy day and a in the Mud hole gun.

My old 98-8mm is my Mud hole gun....No I don't want it in the mud..
 
You stated that the barrel slugged .313 and you are shooting.311 bullets!
Do you think that may be a big part of the problem?

The rifle grooves measured in at 0.313" and the lands at 0.301". From my understanding that is typical of a good bore Mosin Nagant and should fire the 0.311"-0.312" stock sized bullets without much of an issue. Hornady does sell a .312 diameter bullet. Maybe I will try a box of those and see if it helps at all.
 
I would take it out of the stock and bench clamp it then run a clip through..If it doesn't hold a couple inches at 100 yards I would chuck it..
Sounds like you did plenty of work and I would like to see a photo. Never liked the long barrel, the safety and rimmed ctg, so never owned/shot one.

Oh! QT: [I had the stock off I milled out all the area in the stock ahead of the receiver and checked it for clearance.] looks like you covered that..so my suggested bench test covered.

Still you need a rainy day and a in the Mud hole gun.

My old 98-8mm is my Mud hole gun....No I don't want it in the mud..

I haven't fired it outside of the stock, however it has been fired with the original wood stock and the plastic stock with the same results.

Pic of the rifle and one of the bolt head.
5454455.jpg
516516151.jpg
 
I've worked on over 200 of them, from scope mounts and cut/recrowns to re-barrels...

Bullet diameter is most likely contributory to lack of accuracy.

Particularly on wartime rifles (though, those from the Tula factory are almost always better than those from Izhevsk), concentricity is horrible.

When threading for a brake, it's not uncommon for me to take a .010-.015 depth of cut and have one side of the barrel completely untouched. Impossible to know whether it's "straight", but off-center- or if it's wandering all over the place down the length of the barrel. Obviously, if the bore is not parallel to the line of sight lots of issues can manifest from lousy harmonics to inconsistent accuracy.

When you cut/threaded the muzzle, how concentric was the bore, to the OD of the barrel?

Cutting (length) as you did is usually the correct path (I generally go 20"-22") as the long, skinny military contour heats quickly and strings shots; shortening stiffens the barrel and usually improves harmonics.

I doubt it will make much difference because of the oversize bore, but my "go to", generic load for these that seems to hit the node for most is the 174 SMK over 43.5 of Varget, seated to the lands.

Problem with these rifles is the lack of .311, match grade bullets. If you want to build a real shooter off the MN action, re-barrel it (true the receiver face, lap the lugs, and square-up the recoil block on the mill) using a match-grade .308 barrel.
Huge array of boolits are then available, and most die sets include a .308 expander ball for this purpose. Becomes a 'whole different animal when you can load .308 VLD's instead of relying on the .311 SMK solely.

The floating bolthead allows these crude actions to be capable of sub-minute accuracy easily, when a quality barrel is used and it's correctly bedded into an aftermarket stock. The Russians won the Olympic Biathlon in '76 with a MN action in a custom rifle chambered in 6.5 Vostok (54r necked down to 6.5 mm).
 
Qt; [I haven't fired it outside of the stock, however it has been fired with the original wood stock and the plastic stock with the same results.]

But you cleared the stock so much as good.
Surprised it shoot poorly, nice looking gun, auction material perhaps?
My guns mostly .002/.003 clear any touching

I used to think they (Mosin Nagant) were Ok/good guns but never liked/owned one/them.



QT[to take a .010-.015 depth of cut and have one side of the barrel completely untouched.] I was surprised to find some name brand barrels are not very true for center.

Always thought that(.010-.015)would cause heat gain wondering...Interesting to take such a gun and target with one shot then cool for a good tome , then another one shot.If I was still doing a lot of shooting I would test that..
 
Re oversized bores, I've got a couple No4 Enfields that slug .314+, that will group 1/5th the size he's getting with .311 bullets, and iron sights.

And a Winchester 1917 I had, with a 5 groove left hand twist 303 spec barrel that slugged .314, shot .308 bullets far better than what he's getting as well.
 
I've worked on over 200 of them, from scope mounts and cut/recrowns to re-barrels...

Bullet diameter is most likely contributory to lack of accuracy.

Particularly on wartime rifles (though, those from the Tula factory are almost always better than those from Izhevsk), concentricity is horrible.

When threading for a brake, it's not uncommon for me to take a .010-.015 depth of cut and have one side of the barrel completely untouched. Impossible to know whether it's "straight", but off-center- or if it's wandering all over the place down the length of the barrel. Obviously, if the bore is not parallel to the line of sight lots of issues can manifest from lousy harmonics to inconsistent accuracy.

When you cut/threaded the muzzle, how concentric was the bore, to the OD of the barrel?

Cutting (length) as you did is usually the correct path (I generally go 20"-22") as the long, skinny military contour heats quickly and strings shots; shortening stiffens the barrel and usually improves harmonics.

I doubt it will make much difference because of the oversize bore, but my "go to", generic load for these that seems to hit the node for most is the 174 SMK over 43.5 of Varget, seated to the lands.

Problem with these rifles is the lack of .311, match grade bullets. If you want to build a real shooter off the MN action, re-barrel it (true the receiver face, lap the lugs, and square-up the recoil block on the mill) using a match-grade .308 barrel.
Huge array of boolits are then available, and most die sets include a .308 expander ball for this purpose. Becomes a 'whole different animal when you can load .308 VLD's instead of relying on the .311 SMK solely.

The floating bolthead allows these crude actions to be capable of sub-minute accuracy easily, when a quality barrel is used and it's correctly bedded into an aftermarket stock. The Russians won the Olympic Biathlon in '76 with a MN action in a custom rifle chambered in 6.5 Vostok (54r necked down to 6.5 mm).

What's interesting is I have a couple of other Mosin Nagant Rifles and they all slug right at 0.313" and those shoot way better with the .311's despite being in old wood stocks with iron sights. Right now the only hand-loads I have done are the 174gr SMK over 42gr of Varget in PPU brass. If something is wrong with the barrel I will likely sell it or hang it. It's not worth it to re-barrel it.
 
"I was also looking at the bolt. It seems as though one of the lugs is only contacting 1/2 way. I don't know if that would be enough to cause this big of an issue."

Maybe this is the root of the problem? If the locking lugs aren't interfacing with the bolt properly, the rifle might be firing out of battery, which can go unnoticed if only one lug is failing to lock. I recommend that you compare the dimensions of the bolt lugs and the recesses within the receiver; examine both the functioning lug and respective recess, and the non-functioning pair. They might have been improperly milled or damaged at some point during the rifle's life.
 








 
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