On those old milsurps you can clean forever and never get them really clean with patches and brushes. For a major improvement, try an Otis-style electro-chemical cleaning ... see link for several homemade versions.
http://www.surplusrifle.com/reviews/copperout/index.asp
I made one up several years ago mainly for a Steyr M95 I had with a super cruddy bore. It did work pretty well but the hassle of using it wasn't worth it to me.
Bryan, the one in the post IS a bit complicated to make up. One can be made a LOT quicker, easier and cheaper than that.
How to Make a Quick, Cheap, and Easy Lazy Bastard's Electronic Bore Cleaner
1) rubber stopper sized to insert into your gun's chamber with small pilot hole centered in the small diameter end to receive and hold the pointed tip of a steel rod;
2) small diameter (a wire gauge diameter) mild steel rod long enough so that 2-3" extends beyond the length of the gun barrel when fully inserted;
3) heat-shrink tape or electricians tape to insulate the steel rod where it would contact the end of the barrel. Put another 2-3 layers of tape insulation about halfway down the rod length if you'd like to be sure it won't metal-to-metal contact the barrel;
4) insert the rod into the barrel, and hold the rubber stopper in the chamber so you can guide the rod's sharpened end into the pilot hole. Then push the stopper firmly into the chamber and press it to form a water-tight seal;
5) make up a solution of 50% household liquid ammonia and 50% distilled water, or 25% ammonia, 25% white vinegar, 50% distilled water. Pour it into the barrel filling it up to the top, using a little funnel if you need to;
5) connect 2 C-cell batteries in series ( +-+- ) by putting them end to end and taping them onto a paint stir stick... tape at the battery joint to hold them together at the same time. Tape to make sure the batteries stay connected together;
6) get 2 lengths of multi-strand copper wire and strip a half-inch or so off the ends of each wire.
7) tape one wire end to the + end of the battery series and tape the other end of that wire to the gun sight;
8) tape the other wire end to the - end of the battery series and tape the other end of that wire to the bare end of the metal rod in the gun.
9) if you did everything right, you should see the solution in the barrel begin to bubble fairly soon. Leave it for 45 min. to an hour, then pour the black grody gunk out of the barrel, swab it, and admire your much-cleaner bore. You'll have gotten rid of dirt, metal deposits and other unclean nasties.
You may have to do this twice or three times. It WILL come shiny clean eventually, and with almost no effort.
Is this a great country or what!?