I picked up a Rem 513-t, and I want to shoot it off a bipod. These things have a rail on the forend that's drilled and tapped w/ a bunch of different positions for the front swivel. I'd like to leave the rifle original, so rather than retapping the hole to match the pitch of a machine screw swivle stud, I'm thinking about simply figuring out the pitch and making a stud w/ the proper thread to match the rilfe. Can anybody tell me what the specs on that hole might be?