Improving Old Barrels

[TheAbe]

There might be other posts on this topic, and surely on the subtopics it will involve, but how does one go about improving the performance of old military rifle barrels?

I have an Dutch M95 KNIL carbine and an M91 Carcano long rifle that both fail to stabilize their respective bullets the majority of the time at 25 and 50 yards. Targets have bullet-shaped holes instead of round holes in them. Both barrels slug at .267” and I’ve tried nominally .263”, .265” and .268” jacketed bullets, with no noted improvement. The KNIL has dark, worn grooves with a fair bit of pitting, while the M91 has stronger rifling, but also a fair bit of pitting.

Between re-crowning, fire-lapping, and other processes, what steps would others suggest I take and in what order, to attempt to get these rifle barrels serviceable again?

[steveu]

I have found that using "J" bullets, flat base, round nose work best.

[akajun]

If they’re keyholing with jacketed bullets
Not much you can do other than rebarrel
You can try to counterbore if it’s a muzzle erosion issue but unless you have a lathe, generally not worth it

[Hannibal]

What you are describing is 'keyholing' and it indicates a bullet stability problem. Simply put, the bullet is not spinning fast enough to stabilize. In order to be stable a bullet has to spin when fired. Like a football for instance. If there is not enough spin then the bullet will wobble and turn sideways, which is why you have the bullet shaped side profile in your targets resembling the old skeleton key keyhole. You may already know that but if not it's necessary information to understand the problem.

The bad news is if the bore of your barrels is damaged enough the only viable options you have is to have the bores sleeved with rifled inserts, overbored and new rifling cut which will also require cutting a new chamber or replacement of the barrels.

Firelapping will only increase the bore dimensions and remove more rifling. It's a problem crowning won't correct as it's not just an accuracy issue, it's a stability issue.

I'd suggest finding a competent gunsmithing with a borescope and the knowledge to interpret the images to assess the condition of your bores. Only then will you know for certain what you are dealing with.

[TheAbe]

If they’re keyholing with jacketed bullets
Not much you can do other than rebarrel
You can try to counterbore if it’s a muzzle erosion issue but unless you have a lathe, generally not worth it

I’ll try everything else I can first, if for no other reason than the experience. The KNIL may have some muzzle erosion issues, so I’ll look into counterboring.
If this does become my eventual solution, where can one go to get a new barrel made to the appropriate patterns of these rifles? I’d save up and put the money in if I could get something made that would be the right profile externally and would be cut to accept standard .264” projectiles intended for modern (and old) 6.5mm cartridges.

[TheAbe]

I’ll ask around a couple of long-time shops in the area to see who would recommend a smith. Unless anyone here has recommendations for a good smith in the Twin Cities, MN area?

[schutzen-jager]

is it actually pitting or dark fouling spots ? - try plugging filling bore with white vinegar, let soak for an hour, + than give it a good scrubbing with snug fitting brush -

[TheAbe]

White vinegar. I’ll give it a shot. Fairly sure it’s pitting though, as I’ve given both a good cleaning with Hoppe’s and a wire brush cleaning bit...100 passes on the Dutch.

[Ford SD]

Never had any real bad ones but try

cleaning-with-peroxide-and-vinegar try 15 min flush / clean / repeat as required/ clean / oil
and clean it again with reg gun cleaning stuff in a couple of days as more stuff will loosen up and come out on a patch

https://www.marlinowners.com/threads...vinegar.14470/


you can also try plugin the barrel and filling the barrel with eds red (cleaning solution) muzzle down overnight

cast bullets with a gas check use a round nose or a flat nose and do not try to push it too fast try in the 1500 to 1800 fps or stop when groups open up

[schutzen-jager]

forgot to mention - keep vinegar off of any blued surfaces ! -

[Shawlerbrook]

I had some pretty ugly bores shoot pretty good. If the barrel is as clean as you possibly can get it and you are shooting proper sized bullets and they still keyhole the a replacement barrel is the only option.

[rockrat]

I would suggest plugging the bore, filling with transmission fluid and let it sit for a week, then scrub.

[ShooterAZ]

I have had a few sewer pipe barrels "wake up" after shooting several dozen paper patched boolits through them. I've even coated some of the patches with a light coat of JB Bore beforehand. The barrel gets mighty hot afterwards, but it does a really good job of cleaning them out. Might be worth a try, I would.

[TheAbe]

Some fun suggestions coming in. Exactly what I was looking for. At this point, these barrels aren’t so much blue as brown... I’ll look at transmission fluid first, then patched and even cleaning polish embedded boolits.

[LAGS]

I had a Lee Enfield that keyholed no matter what I shot or at any distance.
I soaked the bore with Vinegar for several days.
That was to loosen up any rust.
Then I soaked the bore several times over a week with Ammonia to remove the copper fouling.
Then I soaked the bore with ATF for several days.
I lapped the bore by hand with a tool made out of epoxy and an old cleaning brush.
After all that work , it started shooting way better.
The slugs that shot the best were lead Boolits.
They were heavy weights, cast with very hard lead.
And sized to fit very snug to the bore diameter.
The powder loads were not that hot of a load and I used slower burning powder and kept the speed down under 1200 fps.
Light Boolits still keyholed as did jacketed bullets at higher speeds.

[TheAbe]

I think the KNIL will be the first project, both because it’s shorter and because it’s worse... here is a rough photo of what I’m starting with for the interior of the barrel.

[zymguy]

I’ll try everything else I can first, if for no other reason than the experience. The KNIL may have some muzzle erosion issues, so I’ll look into counterboring.
If this does become my eventual solution, where can one go to get a new barrel made to the appropriate patterns of these rifles? I’d save up and put the money in if I could get something made that would be the right profile externally and would be cut to accept standard .264” projectiles intended for modern (and old) 6.5mm cartridges.

What are your goals for the rifles , I don't know your rifles but i think the 91 is a small ring Mauser. That means that a take off savage barrel in 6.5 Creedmoor which are cheap and easy to obtain could be cut with a new tenon and chambered in your 6.5 Probably not enough there to replicate the military barrel but itd get you shooting. For more dough you can probably find a military style correct pre fit.

[M-Tecs]

I’ll ask around a couple of long-time shops in the area to see who would recommend a smith. Unless anyone here has recommendations for a good smith in the Twin Cities, MN area?

You have a couple of issues for barrel replacement. First the Dutch Mannlicher M95 KNIL carbine and an M91 Carcano long rifle are not commonly rebarreled. That limits your cost effective options. Replacement barrels sources are basically limited to eBay or a custom from a blank. From eBay condition and headspace could be an issue. From a blank the cost will exceed the value of the rifles unless they have significant sentimental value.

If they were Mauser based, you would have lots of options for lower cast short chambered or pre-fits.

[M-Tecs]

What are your goals for the rifles , I don't know your rifles but i think the 91 is a small ring Mauser. That means that a take off savage barrel in 6.5 Creedmoor which are cheap and easy to obtain could be cut with a new tenon and chambered in your 6.5 Probably not enough there to replicate the military barrel but itd get you shooting. For more dough you can probably find a military style correct pre fit.

Per the Frank de Haas book "BOLT ACTION RIFLES". the Italian Carcano M91 shank is .805 long including .050 unthreaded dia .968 at the rear, outside diameter of threads 1.065 with "approx 14 V threads per inch".

[hoodat]

I've got a few that were pretty crusty, and I used strands from a Frontier 45 scrubby, wound around a bronze brush with PB Blaster. (Kroil would prolly be better). I kept at it, because there was nothing to lose, and pretty soon I was convinced that the corrosion was gone. The rifling doesn't look great, but there is plenty of it there, and both rifles shoot pretty darned good, and no key holing. One is a K98 Mauser, the other a sporterized Enfield two groove. I've since shot plenty of cast and jacketed through both of them. jd