Cleaning a Nasty Rifle Bore

[JSnover]

I'm no expert, but here is what I've had the best luck with on very rough & fouled bores. Use the high strength liquid bore cleaners with multiple over night soaks, etc. or whatever the directions recommend. Then for the coup de grace, JB bore paste. Scrub until you're tired & can't do more. Finally, clean any paste goo out with Hoppe's & accept that now your barrel is as good as it gets.

^^That!
My current favorite is Kroil. Plug the bore and let it stand in a bucket overnight. Brush it out the next day and repeat as often as it takes. Finish with JB.

[uscra112]

Kroil can't touch copper fouling, although it does get powder residue pretty well.

[dogrunner]

Screwed up bores and accuracy are not mutually exclusive. I once installed a ctg. conversion cylinder for a friend into a Ruger OA that had an utterly hopeless looking bbl...........shot tiny clusters with factory .45lc and just as good with my handloads...........I would have not believed it had I not seen it! Too, I recently acquired an old model 14 Remington pump in .32R........bore looked worse than that Ruger but after a LOT of scrubbing it began to look as tho it might have possibilities........course with that caliber bullets are problematic............as in unobtanium...........brass can be had for a buck a case from Graf's & is of good quality.........had to buy a mould from accurate for .321's and salvaged a buncha .323 8mm RN.........all show some promise, but that's only if you call over an inch at 50 'promise'!..........But all said, after my experience with that Ruger I'll keep on keepin' on till I reach some kinda conclusion. Frankly, if it wasn't such a damn oddball I would consider a rebore.....but then I'm into a different mould et al.....Still, I keep thinkin' of that ragged coal mine Ruger and................

[Tom in Pittsburgh]

Thanks for all the input, commiseration and suggestions. Took all of that to heart and scrubbed (and scrubbed and rescrubbed) the bore. Shooter's Choice was in there, along with brake cleaner, a phosphoric acid rust remover and JB. Finally deciding that I wasn't going to get the bore any cleaner, I headed out to the range yesterday morning (Dormont-Mt. Lebanon Sportsmen's - between Pittsburgh and Washington, PA). Settled in at a 50-yd bench (I'm 75 and have never downed a PA whitetail farther away that that) and fired a 3-shot group to start. The result was a diagonal string about 6-3/4" end-to-end. Pretty disappointing. Ran into a much more accomplished rifle shooter friend. He watched me fire another five shots - these sprayed into a group maybe 13-1/2" across. I handed the gun to him and he fired a 3-round group. His was about a 5-1/2" group.

He thinks the bore is shootable, but that it would benefit from more work. Based on a recommendation from him and from another accomplished rifleman who showed up, I ordered a set of Tubb's .323/8mm bore-lapping bullets when I got home.

My friend also suggested taking a harder look at the way the stock is bedded - so that's on the project list, too.

So more work ahead. Will post another update when I have more to report.

Thanks again for the interest and suggestions.

[wilecoyote]

I have inherited a WW2 bringback - an 8MM Mauser rifle that was originally a pre-WW2 commercial German hunting gun, but was unfortunately bubba-ed once it got into the US. A late uncle used this gun as his deer rifle for years, and I would like to take it out for deer here in PA later this year. An experienced rifle shooter has told me that, scrub and scrub as I may, the bore is still barely shootable. I think that's due to years of improperly cleaned/removed powder and copper fouling and not actual bore corrosion.
I was going to attempt to cobble together one of those low-voltage electronic bore cleaners (plenty of DIY instructions online), but another experienced shooting friend has counseled against that - he's afraid it would remove actual metal from the barrel. So - before I go off and buy an iron rod, ammonia, wires, etc. - I would like to try one of those modern "miracle" foaming bore cleaners. Supposedly an overnight application will remove all kinds of fouling/gunk. There are several brands out there (Sharp Shoot R Wipe-Out, Shooters Choice, Red Devil 0921 Foam & Fill, Allen Company Cyclean, etc.) Important to note - I don't believe this gun was ever fired with "plain" lead bullets, just jacketed ones. As a result, I don't think any of the old fouling in the bore is lead or lead alloy. Just thought I would see what kinds of experience/recommendations some of you may have?
TIA
PS Apologies if this has been covered before...

I'm not even listing my experiments on Mausers, but in my experience Forrest Foam, when used according to the instructions, works efficiently, with less operator fatigue and less risk to the inside of the barrel, obtaining the result where the most disparate products have failed.

[GregLaROCHE]

Depending on how bad the fouling is, you may want to try some fire lapping with fine grit. Checking each time how much is being removed.

[Hannibal]

5" @100 yds is probably realistic with an abused military bore. Sorry to say but there it is.

[elmacgyver0]

Not in that time period , or really at all
It only reacts with rust.

I built a couple semi-auto pistols and parkerized the barrels, active ingredient is phosphoric acid.
I failed to plug the barrels before parkerizing, low and behold it etched the bores and they leaded something fierce when shot.
It took a lot of work and time using a wire bore brush wrapped with stainless steel pot scrubber material sprinkled with Comet scouring powder to smooth the bores up enough to be usable.

It only reacts with rust. Myth Busted!

[Milky Duck]

I took a budies tired old 6.5x55m mauser and plugged muzzle end of barrel filled barrel with CRC 5.56 overnight then scrubbed it with a .270 bronze brush as didnt have a 6.5mm one.... gave it a heap of passes from chamber to muzzle then gave it a regular cleaning...it came up a lot better than before....
many bores look terrible but still shoot OK.
bottom line if it shoots to say a 3" group and you normally only hunt deer sized animals and shoot at ranges of 100-150 yards,you can still reliably put your projectile into the vital area of deer with 100% certainty if you do your bit...the average deers vital area is considered 8" give of take..elk are bigger and fallow smaller but not by a huge extent.
heck litterally thousands of deer were shot here with SMLEs and fmj ammunition..the SMLE was only ever a 4 moa rifle FROM NEW... that was its specs as a battle rifle... for sure some were better but a lot were worse. some careful considered reloading will help...speer Jword projectiles have good reputation in tired bores due to being soft and flat based....hmm that sounds like a soft casts MO.... good luck and dont give up till you have given it a plurry good try.

[Milky Duck]

definately look at bedding etc..action screws too.... and if as you say 50 yards is your normal shooting range...you only need to get group size down to below the magic 4" at 50 yards...which should get you your venison ethically out to hundy yards....

[Hannibal]

definately look at bedding etc..action screws too.... and if as you say 50 yards is your normal shooting range...you only need to get group size down to below the magic 4" at 50 yards...which should get you your venison ethically out to hundy yards....

I'd not shoot at a deer if my rifle will only group 10" @100 yds and with a 4" group @ 100 yds that's probably being generous. But that's me.

The action/barrel would have to be practically flopping around in the stock to shoot 4" @100 yds.

[Milky Duck]

so you wouldnt go and use a smooth bore shotgun either????
or a muzzle loader????

see its all relative.
get in as close as you can,then 5 yards closer.

[indian joe]

I'd not shoot at a deer if my rifle will only group 10" @100 yds and with a 4" group @ 100 yds that's probably being generous. But that's me.

The action/barrel would have to be practically flopping around in the stock to shoot 4" @100 yds.

more to the point can you hold a 4" group from your field hunting position with a dose of buck fever thrown in ??
Tell me you can shoot MOA in the field, first thing you'll hear is show me ! followed soon after (in most cases) by whoops dunno what went wrong there !
talkin about hunting here not stand shooting or varmint sniping from a rest...............

[nueces5]

I have had a Mauser like this, in my case what worked was to use different methods and different cleaning liquids
a couple of liters of boiling water at first
hoppes 9, was the one that worked best
then a couple of household cleaners
and repeat

[Texas by God]

Recently I bought a 1916 Oviedo 7x57mm Mauser. After soaking all night with Sweets 7.62 solvent and scrubbing with a .30 caliber brush, the bore looked fairly good.
Yesterday I shot it at 40 yards with Federal 175gr RN ammunition. Against a one foot diameter ShootnC target, only one bullet hit the target. I'll slug it to confirm that the bore is oversize- the last one I had was - SO I rebarreled it. This will probably go that route too.
Best of luck with your 8mm, OP.

Sent from my SM-A716U using Tapatalk

[bigdog454]

Ive used diamond dust, if the guns is shootable, I would take a cast bullet that is lubed and rub a little diamond dust in the lube. After firing I cleaned the bore with #9, checked to see if it was clean, if not repeated. Neve needed to use more then 2 cast bullets after using diamond dust.
BD

[akajun]

I built a couple semi-auto pistols and parkerized the barrels, active ingredient is phosphoric acid.
I failed to plug the barrels before parkerizing, low and behold it etched the bores and they leaded something fierce when shot.
It took a lot of work and time using a wire bore brush wrapped with stainless steel pot scrubber material sprinkled with Comet scouring powder to smooth the bores up enough to be usable.

It only reacts with rust. Myth Busted!

your confusing parkerizing solution being heated with cold phosphoric acid solution. SImilar but not the same. But what do I know, I just have done both. Try sticking your blasted parts in cold parkerizing solution for a while and see what happens

[akajun]

Thanks for all the input, commiseration and suggestions. Took all of that to heart and scrubbed (and scrubbed and rescrubbed) the bore. Shooter's Choice was in there, along with brake cleaner, a phosphoric acid rust remover and JB. Finally deciding that I wasn't going to get the bore any cleaner, I headed out to the range yesterday morning (Dormont-Mt. Lebanon Sportsmen's - between Pittsburgh and Washington, PA). Settled in at a 50-yd bench (I'm 75 and have never downed a PA whitetail farther away that that) and fired a 3-shot group to start. The result was a diagonal string about 6-3/4" end-to-end. Pretty disappointing. Ran into a much more accomplished rifle shooter friend. He watched me fire another five shots - these sprayed into a group maybe 13-1/2" across. I handed the gun to him and he fired a 3-round group. His was about a 5-1/2" group.

He thinks the bore is shootable, but that it would benefit from more work. Based on a recommendation from him and from another accomplished rifleman who showed up, I ordered a set of Tubb's .323/8mm bore-lapping bullets when I got home.

My friend also suggested taking a harder look at the way the stock is bedded - so that's on the project list, too.

So more work ahead. Will post another update when I have more to report.

Thanks again for the interest and suggestions.

It seems like it wants to group, no keyholed bullets? Take an unfired round and drop the bullet in the muzzle and see how close to the case neck it will go, ie an unoffical "muzzle gauge" . Many of the these old guns have fishmouthed out muzzles from cleaning rods and improper cleaning over decades. This allowing gas to escape and affect the sides of the bullets. If the muzzle swallows the bullet and it gets anywhere near the case mouth its bad.
The Russians would counterbore the barrels on mosins to fix this in order to keep the original barrel length but you can also just cut back and crown the barrel to good rifling and get the same result. I fixed a 30-30 Model 94 that had this issue by making it a 16" carbine. The old 20" barrel would swallow a bit of the case mouth too. Went from pie plate groups to 2-3" groups at 100.

[Hannibal]

If the OP wants to potentially save some time slugging the bore might be prudent. No point in taking the time to cut and re-crown the barrel if the entire bore is full of loose/tight spots.

[john.k]

Even if the bore is wrecked,Ive found that counterboring until the muzzle shows a proper rifling form will generally make bullets stable ,and at least a 4" group at 50 yds.........Im generally against 'fire lapping' as a lazy mans cure .....but if the throat is greatly oversize that shooting jacketed bullets is a waste of components,then IMHO,whats needed is a smooth surface in which the diameter reduces toward the muzzle..........old gunsmiting books describe methods of lapping barrels so as to preserve the form of the rifling,while enlarging the bore generally to use a larger diameter bullet.