ORIGINAL: bronko22000
mcfadden - you may want to try and lap the bore. First you will need to make a bore plug. To do this get yourself a new 45 cal bore brush. put a couple of damp patches in the bore about 6" down and insert the brush threads out and masked. Pour molten lead into the bore around the brush and let solidify. The lead will not stick to the steel.
Once the 'plug' cools remove it from the barrel. and take out the patches with a worm. Run an oiled patch down the bore then coat your plug with J-B compound or a Comet Cleanser paste and run it back and forth down the bore. You will have to line up the rifling in the barrel with your plug every time you put it in. And this plug will only be for this barrel.
It may work and save you the expense of buying a new barrel. Just don't over do it.
You may want to shoot it before you go to all the trouble of laping the bore and pouring molten lead into it. My son didn't clean his ML at the end of hunting season, it was froze up tight, bore wasdirty and pitted. I cleaned it withbrake cleaner and it shot fine to 100 yards, never tried it further than that. Chap Gleason