I'm trying to clean out a +100 year old Winchester Model 1890 for a friend. The bore is best described as black and "lumpy". I'm hoping it is decades of built up copper and powder deposits and not corrosion. But it is probably rust.

Test firing with open sights gave me a 3" group at 30 yards.

I used a copper solvent on it for a while and got nothing out. So I cleaned the bore with denatured alcohol to prep it for electrolytic cleaning. Using the lead acetate solution removed nothing. I've electrolytically cleaned a lead fouled 44 magnum bore and the lead comes off very quickly, so I don't think this bore has much lead in it.

I've trying the copper solution now. After a few hours I emptied out the solution and some black fouling came out; not sure if it is corrosion or powder residue. The solution came out the original blue color and the electrode was not plated with copper.

I'm going to leave it connected to the DC voltage for several more hours to see what happens. I will be cleaning the bore with denatured alcohol between attempts at electrolytically cleaning as using a petroleum based solvent/cleaner coats the bore and resists current flow.

Any suggestions? Thanks.

I'm watching this thread. I have a Model 1906 with less-than pristine bore. It will still shoot in an inch at 25 yards, but I was hoping for better. It doesn't seem to want to come clean either.

They reach a point wherein they don't come clean, fortunately many still shoot good but some are hopeless..Ive seen this mostly in old Winchesters and double rifles..The slower velocity calibers seem to shoot better than modern hi vel calibers once they get bad..