Thanks for the response Tim. I MAY start working up some loads gradually, at my own risk of course, but I might end up being too chicken (smart?) if I don't hear what I'm hoping for from H&R. I half expect them to give a non-committal attempt to avoid any liability rather than a straight answer, but we'll see! If I get an answer from them, I'll make sure to post it here.
For any 45 Colt guys reading the thread... any suggestions for powders that are more appropriate for the 20 inch barrel, or at least places I could look? I've tried checking out Alliant, but their reloading info is down... and I'm too entirely exhausted to look else where tonight.
Thanks again for the info.
Bryan