"I wound up using 0000 steel wool on a brush driven by a variable speed drill and eventually got the rust out and the bore actually had a little shine to it, but the rifling looked kind of ragged."

Never spin anything in a rifle bore!!!

So, my dad found this somewhere, made one, and liked it, so I'm making one tonight.
Real easy:
3' 1/4" steel rod, 30 AMP battery clips, heat-shrink tubing, a tapered rubber plug that will fit in your bore, a funnel that will do the same, a D-cell battery and some wire.
The whole thing cost me less than $10.
Heat shrink one end of the rod, and crimp while hot (lighter works), then measure to length of your barrel and heat shrink a 3" piece right there. These are the insulators. Tape the wires to the battery, noting positive and negative.
Tap the rubber stopper into the chamber, set upright securely, fill with equal parts white vinegar, ammonia and distilled water, drop in the rod, insulated end down, make sure your crown is insulated from the rod touching it, clip your negative to the end of the rod and the positive to any part of the rifle that's handy. I flattened the clip out, and squeezed it onto the stem of the bolt handle.
Leave for 20 minutes, empty and run a patch or two, repeat till clean.
If your rod gets full of copper and lead, just borrow a buddy's rifle, and switch the polarity. Clean as a whistle.

The only improvement I can see whould be to find the perfect little o-ring that could roll up and down for different length barrels, but still fit just inside the bore of your smallest.
Beats the hell out of scrubbing all day.

I'm on my third can of Wipe-Out and I still use a brush in my bore. There's just no substitute for a scrubbing. I've experimented with it and found that brushing the bore removes additional fouling that Wipe-Out and patches alone do not get. I do like it a lot, but it's not a miracle cleaner.

Or you could just use WipeOut...

It doesn't get out lead though. But for copper, it's a lot easier to use than any electrical contraption. Works just as well, I'm sure-- as it does a perfect job. Try it once, and you'll never brush a barrel again.

The $10 bucks for an electronic bore cleaner is a great deal, it�s just the $450 barrels you hafta buy each time you clean them that�s the problem. You should clean them with dynamite - the end result is the same, but it�s a lot more fun to watch.

Electrolysis is a great way to pit a bore. It is amazing how quickly you can do it with just a little ole battery. I would strongly recommend that you not do this.

Make no mistake serious damage can be done if you select the wrong voltage. Too low a voltage and you will not cause the copper to go into solution to plate onto the rod, so no damage there. Too much and you will dissolve the copper and the iron behind it. As I understand it, the voltage determines what metal is electrolysed, and the Ph of the solution determines how fast it will happen, ie a low Ph solution will draw a lot of current and the reaction will happen quickly. Strictly speaking if you select a voltage just above the correct voltage at the end of the reaction nothing further should happen. I did Physics in 1973 so my memory is a bit foggy.

I've used this device plenty times using household ammonia and 3V (2X1.5V in series) and it works like a charm. My cathode is stainless steel, so the black copper (II) oxide deposit strips off with a wet wipe. Most of it comes off as a black scum in the foam.

I monitor it very carefully, when the solution stops foaming (hydrogen is given off in the process) I break the circuit. A good clean and I am good to go. I have tested a cleaned barrel with Barnes CR-10 and the patches come out clean with no blue copper staining.