Need Help Cleaning Rust from Bore.

F

Farmalljon

New member
I just did a little horse trading and ended up with a sporterized 8mm Mauser K98. The finish on the outside is a nice rich blue. The bore is a different story. It was pretty rusty in there. Enough so that when looking inside, all I could see was the lens of my LED bore light. The rest was completely black. I spent a good hour last night with a copper bore brush and some Birchwood-Casey Bore Scrubber. I made so many strokes my arm feels like it's going to fall off this morning. It really helped because now the bore is much brighter...not shiney, but at least brighter. There are a lot of stubborn little "specks" of rust still visible..VERY small ones, but they are there. it basically looks like a dirty barrel that has been shot a lot and not cleaned. Except I can not seem to get anymore rust to come out by brushing the bore. Any suggestions? I thought about chucking up one of my old cleaning rods and a brush into my cordless drill and spinning the brush while stroking it back and forth. Any thoughts on this. I know this will never be a "match" gun. I'm just hoping to get 5" groups at 100yds or so....that would be fine for shooting a deer this fall. Let me know if you have any ideas how to get the barrel on this thing in as good of shape as can be at this point. Thanks....
 
Plug the muzzle with a rubber plug. You can trim a wine bottle cork for this, works pretty well.

Hang it up, muzzle-down, from a peg on the wall. Put a plastic bowl/bucket/etc on the floor under it to catch any drips.

Pour automatic transmission fluid (I prefer Royal Purple) in the barrel until it's full.

Let it soak for a couple days.

Scrub scrub scrub with a bore brush.
 
NO BRUSHES AND DRILL ON RIFLED BARRELS. That's ONLY for smooth bore shotguns. Spinning a brush in a rifled bore will absolutely ruin it.

As above, order some JB Bore Paste and Kroil from Brownell's. Some gun stores stock it.
Liberally soak the bore with Kroil and let soak for 24 hours. Kroil is a SUPER penetrating fluid that can penetrate a crack 1 millionth of an inch wide. It'll penetrate the rust and will soften and loosen it.

Then use several patches with JB Bore Paste and Kroil to polish out the barrel.
This will remove any last traces of actual rust and will smooth the bore as well as can be done.
After the JB treatment, what you have is the best you're going to get.
Any other method will actually remove metal, leaving you with an over-sized bore.
Just because a bore is pitted and frosty is no indication of how well it'll shoot.
Many bad looking bores shoot nicely.
 
Okay, thanks for the advise. No spinning the brush. I'm sjust hoping for 5" groups at 100 yards. I'll check out Brownells.
 
If you can't get it smooth with JB Paste, the last resort is to use a bronze brush with 0000 steel wool wound on it, soaked with Kroil. I did it on a Win 1894 that was terribly rusty and it came out much brighter...not new looking, but it shot great!!!
 
I'd try the auto transmission fluid. You might be pleasantly surprised. I used to rebuild auto transmissions and the fluid is some amazing stuff. And cheap.
 
I had a sporterized No.4 Enfield with a dark bore like you describe. I did the plug the muzzle and soak thing, but used Hoppe’s No.9. A few worn out brushes later, and the rifling showed real well. Still a little dark, but cleaned up okay. It went from 6 inch 100 yard groups to just over 2 inch. Acceptable.
 
After you soak the barrel and clean it, be sure to fire a few rounds through it, and just clean it again, with solvant, and patch it out again, that will help to smooth it out a bit. I bet someone shot corrosive ammo through that barrel without cleaning it. Shame. I have one rifle, with really worn rifleing, its kind of rough, and just after the chamber, the rifleing is worn down pretty bad, that gun is still very accurate, it just takes alot more patches after cleaning than a good barrel. Good luck, the Mauser action is one of the best ever made. Also, if you wanted you can have the action re barreled.
 
I have an old K98, 8MM, VERY rough shape, dark bore (after 2 days of scrubbing and LOTS of Hoppes #9. Its my camp gun, a spare. For $40.00 2 decades ago, I couldn't pass it up. Even with a rough bore, it will stay on a paper plate at 100 yards. No 5" group like you are hoping for, but good enough for a cheap spare.
 
If you can't get it smooth with JB Paste, the last resort is to use a bronze brush with 0000 steel wool wound on it,
Click to expand...

I have done this on muzzle-loaders that were put away for years without cleaning, and it works well...
 
Here's what I did when I
bought a 444 with a rusty bore.
I bought a 3/16 steel rod;
Plumbers' teflon tape ;
2 "d" cell batteries;
3 or 4 neoprene stoppers;
2 lengths of 18 ga strand wire
1 bottle of ammonia.

I found the right size stopper
and put a hole in the middle
with a nail,I then wrapped layers
of teflon tape in different spots on the steel rod.
This prevents contact to the bore.
I fashioned some wood pieces
to hold the batteries in series and squeezed
the 2 wires -one on each end with a plastic clamp.
I then placed the stopper in the chamber and inserted
the rod thru the muzzle to stick it in the stopper.
Pushing the stopper/rod firmed in place to prevent
leaks,I then filled up the bore form the muzzle
with ammonia and attached each wire.
one to the rod and one to the barrel.-I used the front site.
you might have to switch wires to get a reaction.
In a bucket I had some paper towels so that I could really
see the gunk.
The liquid starts smokeing and then boiling
and I waited a bit and poured it into the bucket.
holy crap , the crud that comes out of the bore-amazing.
I did this a couple more time and then followed up with
a simple cleaning.you have to neutralize the ammonia with oil.
this was sort of fun and totaly amazing.I had made an outers
electronic cleaning kit for about 4 bucks.
Only work is ,you have you have to keep cleaning off the rod
with a towel to to the reverse electrolysis.
Ron
 
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