can anyone tell me where I could send a 45 redhawk to have the chamber mouths opened for cast bullets? also, have you ever heard of a taylor throat? are they usefull with cast bullets and who does them?

Have you shot this gun with cast bullets yet?  If you haven't, then I suggest you do so.  You may not have a problem.   If you do have a problem, you can try Dave Clements at Clements Custom Guns.  Their are several links on the sixgunner site.

As to Taylor throating, go to www.sixgunner.com and look in the FAQ section.