Ask the guys at Brownells if they know someone who could try this job.

The barrels you indicate are most likely too thin to safely reline. A more usual method, which has been done in the past if there's enough "meat" in the breech end, is to cut the old barrel off just ahead of the breech, drill the breech out, and then solder-in a new full-diameter, full-length rifled tube.

Even if the old barrels are badly pitted, it might still be best to give them a really thorough scrubbing and (non-abrasive) polishing, and than to fire only fully-jacketed bullets through them.

I have seen "slightly used" M.1903 barrels for sale on GunBroker.com. Magazines, too. The Remington parts may be harder to find, but you could try Numrich Arms. (Gun Parts Corp.).

Thank you Steve. I hadn't thought of Brownells. I have been looking for some time on GB, AA, and GA; withought any luck. The 03 mags are going for $150+, and no decent barrels either. The same for the 51(specially the.32). Lots of .380's; but they only made around 2,500 of the .32 51's. I'll give Brownells a try tomorrow.

OK, how 'bout converting both pistols to .380, and saving the original .32 parts for the eventual sale of both entire pistols to a collector?
It's possible that conversion of the Colt requires only a barrel—the same magazine may work for both cartridges. If I'm wrong about the magazine, new .380 magazines cost about $25.00 each.
I dunno 'bout the Remington, but I suspect that it's the same sort of parts-swap.

The 51 would require extensive parts replacement. It's a pretty complicated pistol. The '03 might be doable. I'll look into it; but I'ld still just rather find the parts. Thanks