I have an old 70's Japanese Miroku O/U shotgun I love. Its a "beater" cosmetic wise and not real pretty but a great shooter. Only problem is its rusty inside the barel where you load shells. Its the "coned area" I guess you call it. Down the rest of the barrels its fairly clean and shiny but I do see some other junk in there even after running several patches with hoppes 9 through it.

So, I was going to get a long piece of rod or something that would be as long as the barrel and try and attach it to a 20 guage round wire brass brush and put this into my drill and squirt the crap out of it with WD 40 and high speed polish the cone area and barrels to remove the rust and shine everything up good. But I dont want to F up my barels. Yes/no? Whats the worse could happen? Barells are unobtainable any more.

Just go a little at a time and examine whats happening in the chamber. Don't just drill away for a minute then look... You should be okay to do that, but I wouldn't go crazy. I'm no gunsmith either....

If it shoots good, just oil it and let it alone.

>>>IMO<<< you're not gonna hurt anything with a brass brush and a drill. Like they said above try it, then check it, a little at a time.

If it was mine I'd try some, med to fine, steel wool.

GO FOR IT! IT'LL BE FINE!

If its a 'beater' - then like Schanz said - just keep it LIGHTLY oiled and use it. Miroku made some really good shotguns on their own - and then they made the Browning Citoris.

Don't mess with it yourself. Take it to McClelland's gun shop. Down near the Dallas Arboretum. They've been there 40 years. Main shop isn't much to look at, it's in a bad part of town after dark, but go to the back area (service area) and you'll see multiple dozens of guns on racks, being repaired and restored.

Just take the barrel if you want. They'll hone it out for under $40 (usually). They will take it back to factory specs.

Website: http://www.mcclellandgun.com

x2, better safe then sorry

Like a couple of others said brush it down or use steelwool and oil it down good. Just my opinion but if the rust is bad, honing won't help, visible rust is oxidized metal so the amount of rust removed relates to the amount of metal lost from the barrel. Honing it will smooth it out but honing also removes metal and that will not bring it back to factory specs, it is only increasing the diameter of the bore or chamber. Its just a cosmetic fix!

use something like a dremmel with buffing tips and some white polishing compound. It will polish up whats there and remove the rust. less abrasive the steel wool

Quite a bit of what you're seeing is probably plastic deposited from shells. It looks a lot like rust and as far as I know, none of the typical gun cleaners get it out over the years of shooting so it builds up. I had the same problem. I got some valve lapping compound (nasty black stuff), wrapped some 0000 steel wool around a 12 ga brass brush, coated it with the compound, and used my drill to hone it out. Just like honing an engine cylinder. That was the only way I got mine clean. THEN, you have to polish it because the lapping compound will leave it with a smooth but satin finish. On eBay, you can get rubber polishing bits for a Dremel tool. They will polish it to a mirror finish.

Whether it's rust or plastic, this will work.

Doc's in Carrollton may be lots closer for you. He's on the corner of Broadway & Keller Springs ( aka Sandy Lake Rd) 1 block east of I-35 just south of the Bush/I-35 exit across the street from the west side of the water plant...or 1 block west of Old Denton. Can't go wrong either way.
+1 on the plastic wad trash idea.
Ron

Instead of the brass brush, I used some Scotch-Brite pads to polish the bore of a couple of old shotguns. I bought the Scotch-Brite pads in a couple different grit sizes and cut them into strips about 1/2" wide and 3-4" long. I threaded a strip through the eye of the cleaning rod tip, and then used my power drill to spin it down the barrel. I used the coarser pads to remove rust, and then the finer one to polish it out. The rust is gone, and the barrels have a satin finish. The shells eject easily, too.