Beretta question

Can anyone tell me what thread is usually cut on the barrel to attach the oversized sleeve? Thanks.

Don't know about anyone else, but I used a 1/2-28

Thanks for the reply. I finished the gun about a week ago. I went with a larger diameter, finer pitch thread, since I made the mating part it didn't really matter. I just wondered if there was any "standard". I haven't had the chance to test fire yet, but I put inserts in the frame rails, set screws under the barrel, etc. Can't wait to see if it helped, it shot very poorly in stock form.