View Full Version : How do I clean minor pitting out of a rifle barrel

July 14, 2011, 08:39 AM
First off, let say I'm a clean freak when it comes to my rifle barrels and guns.

Just purchased an Arisaka 6.5X257 Roberts. $150.00 for a 50's or 60's well sportized rifle, with scope and sling. I believe these Arisakas had polygon rifling. Overall, the gun looks very good on the outside. Very nice Bishop walnut stock and good blueing, a little piting around the muzzel. The barrel looked good when I got it. I've had some old military rifles with pitted barrels that wouldn't shoot a 10" group at a 100 yards. This dosen't look like it is one of them. I haven't shot it yet, as I'm waiting for a 6.5X57 reamer and go gauge to rechamber it. I already have a 6.5X57 Mauser and dies. Rechambering was actaully cheaper than buying custom 6.5X257 Roberts dies. Plus I would still have the reamer and go gauge should I need to replace the barrel.

Anyways, the bore has some minor pitting in the lands. The rifling or groves looked good and shinny. First thing I did was clean the barrel well. First with a copper and then lead/carbon cleaner. As I ran the patches down the barrel I could feel the roughness. To make sure I had the barrel clean, I then put my Otters Foul Out cleaner on the gun. First with the copper and then lead removal solutions. With both, the clean light came on with in 10 minutes.

The barrel is clean, but I can see the pitting in the lands at the muzzel end, not on the groves. I swabed the barrel with a jag and #0000 steel wool and bore oil making about ten to fifteen passes. Barrel got smoother but could still feel some roughness when passing a jag and patch though it. So I tried lapping the barrel with a jag, patch and polishing compound. The polishing compound is in an oil base and is what I use to sharpen clipper heads on flat steel plate for trimming my dogs. With some elbow grease and time it will polish the clipper heads to a miror finish. But in a barrel I was hesitant to doing it too much, so I limited to 15 passes and a cotton patch.

The bore is shinny clean now and the patched jag passes smoothly through it. But I can still see minor pitting in the lands. Is there anything else I can do to restore this barrel?

July 14, 2011, 10:06 AM
But I can still see minor pitting in the lands. Is there anything else I can do to restore this barrel?

Generally no.

See how well it shoots before ding anything more.

4V50 Gary
July 14, 2011, 10:23 AM
No more steel wool down the barrel. You're wearing out the lands and this ruins accuracy.

You can no more un-pit a barrel than you can make fire cold. You can re-barrel a rifle to a fresher barrel or you can have the barrel relined, but pits will always be there.

A pitted barrel can still shoot accurately. You just have to shoot it to find out.

Don P
July 14, 2011, 10:46 AM
Ye old kitchen table gunsmiths at it again. What ever happened to patina?

Old Grump
July 14, 2011, 11:55 AM
Throat and crown are more important, if the barrel is clean your bullet won't notice the pitting. It just needs a good start, a clean barrel and a clean exit.

If it shoots well be happy, if it doesn't try another bullet weight or type and try again.

Good luck

July 14, 2011, 12:37 PM
Some pitting on the lands may not be a real issue, the rifle may shoot fine. Remember that you are shooting a 70+ year old rifle, it is not new and will not be like new. Stop trying to lap it out, you will ruin the bore. If the roughness in the bore concerns you, fire lap the barrel, that is the best option for smooting it out. And keep the steel wool out of the bore.

Also, when you rechamber the barrel you will likely have to set it back a turn, the 6.5-257 has a steeper shoulder than the 6.5X57mm.

James K
July 14, 2011, 04:53 PM
You can be a cleanliness freak until there are snowdrifts in he**, but no amount of cleaning will put back steel that has been rusted or eroded away. It's gone, leaving a hole where it was, and there is no practical way you can ever fill that hole. All steel wool and polishing will do is remove more metal from the barrel and quite possibly ruin it.

If you can't live with minor pitting, then replace the barrel or trade the gun in on a new one.


July 14, 2011, 05:31 PM
Dealing with pitting involves either removing metal until the pits disappear-not a wise move as others have pointed out-or somehow filling them in. Not an option in this case.
I have a 1943 P-38 with a pitted barrel-shoots fine. Also with an old military rifle with a pitted bore and poor accuracy, I would check action to stock fit, screw tension, etc. Remember a lot of old milsurps were hastily assembled by less than skilled labor, probably never fired for accuracy and have not been properly stored for 60-70 years.

July 14, 2011, 06:48 PM
Pitting is a hole, or many of them.
You can't fill the holes.
Just clean and use. I'll bet your accuracy will be just fine.

July 14, 2011, 07:07 PM
How close to the muzzle is it?

If the pitting is at the very end, say just 1" or 0.5" of pitting, just shorten the barrel and re-crown it (or have it done for you). Another option (albeit a stranger one) is to turn the end of the gun into a "false muzzle" (i.e. remove the rifling in that area and enlarge that area so the bullet won't contact it). This was typically done to black powder rifles at one point in time, but I can't see why it wouldn't work for a modern gun. Just depends on your tools, your skill, and if you want to keep it in original or semi-original condition.

July 14, 2011, 07:22 PM
@bapfreak, its called counterboring. It is also common on WWII era rifles, Mosins and Mausers especially.


Depending on where the pitting is, if its near the throat you can set the barrel back and rechamber it, or if near the muzzle cut it down or counterbore. If its in the middle, a custom barrel or a donor is your only option.

Please, for the rifles sake, shoot it first and put away the lapping compound. You should ALWAYS seek gunsmith advice before trying something like that.

July 15, 2011, 08:15 AM
It's true that the rifle can and will still shoot fine, because the 3006 that I passed down to my eldest has a pitted barrel. An old "smith" told me NOT to try to get rid of 'em because it would do more harm to the throat and the muzzle than good.;) Lyman Brooks was his name by the way, down in Poplar-Bluff Mo..... Oh and by the way the old gent I bought it from, and his brother shot some corrsive primered Gov issue through it and never washed it out!!:( This rifle however, still shot 1/4 MOA with handloads at one hundred yds! and still does!!:)

July 17, 2011, 06:46 PM
Let the pits alone. Years back I picked up a 6.5 Arisaka and wanted to cut it to 6.5x55. The bore was so bad I could not push a patch through. I put a stainless brush on a drill and ran it through until I could get a patch through it with out tearing the patch. It was one dark bore when you looked through it. As it was only an experiment, I took it to the range after re-cutting the chamber. It is now one of my favorite deer rifles. At 100 yards it will keep up with any new deer rifle out there. I don't clean it very hard now, I figure the copper fills up the pits. If you want a shiny barrel, I have a .300 Savage take -off that is very nice inside and out. You could not hit a pig pen, let alone a pig in the butt with that barrel. Once the barrel was off, I could see a definite "step" in the barrel. Shiny is not always better.
The barrel is off an "R" model 99 Savage. Make offer.

*If you get the idea to go 6.5x55 with an Arisaka, they made two different twist rates, early and war production.

James K
July 18, 2011, 06:01 PM
"If you get the idea to go 6.5x55 with an Arisaka, they made two different twist rates, early and war production. "

Hi, Gunplummer,

Do you have the approximate date of the change?


July 19, 2011, 07:26 PM
Wow, great response! I'll wait and shoot it. Action has been re-bedded and trigger replaced with Timney adjustable. I have the reamer and I'm just waiting for the Go guage. Barrel will be recrowned when the chamber is recut. Don't believe the barrel has to be set back as the 6.5X57 Mauser shoulder is .0243" longer and .0016" wider than the .257 Roberts. The neck is also .011" larger. The Roberts shoulder to neck is .184" VS the 6.5X57 Mauser shoulder to neck being .189". If it doesn't shoot good, then it will be rebarreled.

James K
July 19, 2011, 09:22 PM
FWIW, those Japanese rifles don't have polygonal rifling, they have Metford rifling. At the time the Type 29 and 30 were adopted, British influence on the Japanese military was very strong, and the British were mostly still using the Lee-Metford.


July 20, 2011, 12:27 PM
It is hard to pin down a date. The information I can find says some could be 9 as early as 1910-1920. The early twist rate was 7.88 but the change over to 9 was different depending on date and where it was manufactured. Some had 6 groove rifling, some 4 groove. I just recently sold a type 30 at auction and I know that was 7.88 twist and they quit them around 1900.

July 20, 2011, 06:26 PM
A simple rechamber for you 6.5 ariska is the 260 rem. (6.5x308). I did one a few years ago. It was less that a year before they came out with the 260 rem. Simple chamber reamer is all that was needed (plus go and no go of course).

July 21, 2011, 10:43 AM
sc928, This Arisaka has already been rechambered to 6.5X257 Roberts. The current chamber is too long for the .260 Rem. Had it been a normal 6.5X50mm chamber then I would have gone with a .260AI, which I have access to the reamer and Go guage.

July 22, 2011, 07:36 AM
I am too lazy to look it up, but isn't a 6.5x57 Mauser an odd twist rate as far as 6.5's go? Same with the .260. I did a .260 with a 1-9 blank a couple years ago and @ 100 yards it is O.K., but not great with factory 140 Grain bullets. The Arisaka I re-cut to 6.5x55 is very good @ 100 yards, but only with 160 grain bullets, which I hunt with any way.

August 26, 2011, 09:43 PM
Hi, A little update on my 6.5 Jap T38 conversion to 6.5X57 Mauser. Been kind of busy and haven't had time to post. Hand reaming went smooth. I added a Timny trigger. Since T38 barrel were 1:9 twist, I worked up loads with two bullets, 100 gn BTs and 120 gr A-Maxs and IMR 4350 and went to the range once. The 100 gn BTs shot well just under 1.5" to 2" groups. The A-Maxs shot 2" to 2.5" groups. This was with a 4X fixed scope. Only did one shooting as I've been busy. But my F class league well be finishing this weekend and other summer projects are finished, so I'll have more time working up loads. Gun shoots well enough to buy some 7X57 brass and fire form. I think I'll use this gun this deer season.

Harry Bonar
September 3, 2011, 12:30 PM
You cannot "clean-up" pitting!
All you can do is to clean out the rust as good as possible - once rust eats its way into the steel this deep as to cause pitting it will still, if not too bad, still shoot pretty good!
Harry B.

November 9, 2011, 10:46 PM
Another update on my T38 Arisaka.

I had some time to work up loads. 100 gr BTs shot pretty good, but I couldn't get anything heavier to group to my expectations - 1.5-2.0". Plus I had a lot of flyiers. I wanted this for a shooter and hunting and didn't want to put a hole lot of money into it. So I re-barreled this T 38 with a Midway Adams & Bennett .264, chrommoly barrel. Had my gunsmith thread and chamber the barrel again to 6.5 X 57mm Mauser, cut and crown to 22". I cold blued the barrel temporaily.

I purchased an older Hornady reloading book with 6.5 x 57mm load data at a gun show. So I went back to 120 gr, A-Max bullets. The Hornady data for their 120 gr started at 43 grains of IMR 4350 and maxed out at 47.5 grains for a velocity of 2,900 fps. I used Nosler 7 x 57mm brass to form the 6.5 X 57mm case. I loaded in half grain increments from 44 to 47.5 grain. The Adams & Bennett barrel fowled easily and was cleaned after each 5 to 10 shot firing. But the barrel shot better as more rounds were fired. Break was done with previously loaded ammo. Group size reduced as the load charge increased. Best load was 47.5 grains, but bolt was hard to open and velocity was 3,040 fps. According to the Hornady book the 47.5 charge should have had a MV of 2,900 fps. Other than the bolt being hard to open the cases showed no signs of high pressurer. I assume the Nosler 7 X 57mm brass was a little thicker brass. In the end I went back to 44.0 of IMR 4350. this last week, I fired eight shots into a .8" group, MV 2,744 fps. I will used this load for this coming deer season.

Old Grump
November 10, 2011, 02:23 PM
In the end I went back to 44.0 of IMR 4350. this last week, I fired eight shots into a .8" group, MV 2,744 fps. I will used this load for this coming deer season. Looks like you found a perfect solution, congratulations.