I was recently gifted a 98k from someone close to me who passed away and it is in rough shape. I've completely stripped it and dealt with the cosmoline and dirty stock but apparently it was fired many years ago and never cleaned. The rifling appears to have rust throughout the entire length and I've never tackled an issue like this in the past. Wondering what your methods are for dealing with a rusty bore? I've come across numerous methods online but some seem pretty extreme. I'd love to get it back into a working rifle however I have no idea yet about headspace, crown, etc...

Plug the muzzle with a stopper. Fill from the chamber end with Kroil or other penetrating oil. Let it sit for several days. Then drain the oil and hit it with multiple passes with a bronze bore brush, wiping it out with patches in between brushing bouts. (You will likely need multiple brush heads as you wear them out.)

It'll take some elbow grease, but that should make a dent in the rust. You might need to do the Kroil>Wait>Scrub routine several times.

Then, hit it with some foaming bore cleaner, and repeat with the bronze brushes and patches.

Finally, once you get down to where the rifling is distinct and the worst of the rust is gone, take it out and shoot a few rounds through it. (Using noncorrosive ammo.) That should clean out much of what remains that's cleanable.

At that point, it'll probably be about as good as it's going to get using home remedies. Understand that you're not going to get a rusty bore back to being pristine, due to the rust pitting the metal. (But occasionally what appears to be a rusty bore is just crudded with decades of dried cosmoline and dirt, and after cleaning you're left with a sharp, shiny bore. One of my M44 Mosin-Nagants was sold to me super cheap because "the bore was toast", but it actually cleaned up to be one of my nicer milsurp bores.)

There's a further method to clean out rusty bores using a homemade electrolysis tank, but that's beyond a lot of folks' home capabilities. There are also special lapping bullets that you can use to polish out some of the pitting, if you're set up to reload 8mm Mauser ammo.

I will echo what Rougue said but I’d add another step before shooting.

Boil the barrel in a homemade trough made from a section of gutter and a turkey fryer burner. Boiling converts the rust into non-ferric oxide. (Go look up Mark Novak you tube about doing the maintenance and conversion) boil it for three hours each time until all the rust is converted.

Then shoot it and clean it regularly.

https://youtu.be/rShG_F85W1Y

Minute 34:00

And in my (very) limited experience even badly pitted bores can still shoot reasonably well for the types of guns they're encountered in. The pitting makes cleaning harder, but doesn't necessarily make them worthless.

Excellent, thank you! Looks like I've got my work cut out for me. Would be great if it was just old dirt and cosmoline... I'll report back once I make some headway.

Do you reload? If the pitting isn't too bad you can fire lap small pepper pits out.

Sounds like the name of my new band, "Rusty Bore"

We'll be opening up for The Nails and those 44 women in the crowd,

FWIW , I just cleaned up a few M1917's that were VFW rifles,

the bores were crap, from blanks, so not exactly rusty,

I bought some foaming bore cleaner (actually 3 brands) and foamed up the bores and let then sit (muzzle down in a a plastic tub) for a week or so, giving them a squirt every few days,


shot of Aerosol Kroil, 10 strokes with a brush, and a few patches later most turned out very well,

one is still a bit cruddy/rough,

I used Hoppes, Otis and Mp-7? the MP-7 was not listed as a foamer, but it did when I shot it in the bore,

the birchwood casey stuff is like snot,, nasty to clean up

After your Kroil/bronze brush routine you might want to try wrapping a few strands of Big .45 Frontier Metal Cleaner Pad to the bronze brush. P.S. DON'T let anybody tell you it's the same as a pot scrubber, It most certainly IS NOT !

I recently found a wood rasp in a corner of my basement that has seen a bit of water and the old rag it was laying on didn't help a fit. Basically it was a ball of rust with a handle on it. Boiled it for about 2 hours and now I have a wood rasp that has been black oxided and still quite sharp.

Were I in your place the last thing I would do is apply any type of oil. Because oil interferes with the conversion from red rust to black oxide. What I would do is build a pipe of the correct sise to drop that barrel into and use some burners scavenged from some old propane barbecues and build a fixture to boil that barrel. BTW bushing the barrel with a bone dry brush will clean up the dust that accumulates during each stage of boiling. I use a 40 minute cycle time and then brush the work-piece clean while wearing heavy gloves.

Final note, that rasp I converted shows no hint at all of being a ball of rust. I can almost guarantee you that if you take the time to do a conversion on this barrel you will be shocked at how well it cleans up. I will also note that Ferric Oxide is technically a Ceramic and it actually is a coating with a hardness that is notable.