There are a bunch of fellas here that hand reamed their mags to max, so I'd be the last one to tell you that you need to have it done by a smith, the reamer can be rented from GBO sponsor, 4D, click the logo in the upper right corner of any forum page for the sponsor list. I've rented two throating reamers from Fred, he was quick to ship them to me and they worked perfect, others have rented Max and 445 Supermag reamers from him too. If you would rather have a smith do it, I'd contact Wayne York of Oregunsmithing, but be aware that his turn around may be long, you'd have to check on that if you're in a hurry. He's done several rechambers and rebores for me, he does excellent work.
http://home.earthlink.net/%7Eoregunsmithing/index.htmlTrigger jobs done by H&R may cost you, I believe if the trigger is over 5lbs, they'll reduce it to ~3½lbs for free, but if it's already less than 5lbs, they may charge for it, that would be another question to ask about, their email address and toll free number are in the FAQs, if you haven't been there yet, it would be a good place to spend a little time, hint...hint.
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A better place to ask about the muzzleloader barrel is the Huntsman/Sidekick forum.
Tim