Quote Originally Posted by kaferhaus View Post
You've "rolled" the first thread in the reciever. You'll need a strong dental pic or a tap to fix it... otherwise off to a machine shop to have them chase the thread. I've seen it happen before. easy fix if you have the tool(s).

You didnt' have the shank and action threads aligned when you first tried to screw it on.... caused the first thread to roll...
Sounds about right. Rather than pay a smith or machine shop, order your self something like this:

http://www.icscuttingtools.com/catalog/page_359A.pdf

and then you'll have it for the future for less.