I had actually started to persue the custom barrel route, wanting to build a half-stock fowler on my T/C Renegade. The 62cal smooth bore from GM is very heavy for this purpose, being a 32" straight octagon with rifle sights. I did find someone, McC Custom Machine who can/will breech any barrel that will fit and fit/install any extra parts I want, like an underrib, staple, shotgun bead.
I had a disappointing email conversation Friday, 12/19/08, with Scott Keller at Colerain, who wished he could help, but Colerain does not do anything for anything made by T/C. He was gracious, and offered help for any fowler or rifle I wanted to build from scratch, and DID recommend I call Ed Rayle. He even included his number.
I will call Mr. Rayle this week. The most expedient way to reduce weight in the 62 would be to bore it out larger. Then it would drop back in. I could replace the front sight with something lower, and remove the rear sight altogether. But that is a compromise, and a proper shotgun bbl fitted to this stock would be much better......
Hmmm.....I could ask if he would bore it out to 16ga, and taper the octagon....but that much work would probably approach the cost of a new bbl, and I could sell the 62.....
I will keep you posted.