Cumbrian Posted January 16, 2016 Report Share Posted January 16, 2016 (edited) Is there a standard size for the thread of a shotgun bead (modern over and under, not an old English side by side)? I need to re-cut the thread on my Winchester 5500 (1980s but modern enough in all likelihood for this particular purpose). It looks like 2 mm to me but I'd like to be sure. Just found that an ebay seller has new beads in 2.6 and 3.00 sizes, so perhaps that is the answer to my question. If my measurement is correct, that might explain why a new bead in my Winchester was a very tight fit initially and sheared off when I wanted to take it out (to try shooting without any bead at all). May need to get a 2.6 or 3.00 mm tap. Edited January 16, 2016 by Cumbrian Quote Link to comment Share on other sites More sharing options...
subsonicnat Posted January 16, 2016 Report Share Posted January 16, 2016 Probably lock tight in the threads,why it was so tight.. Quote Link to comment Share on other sites More sharing options...
impala59 Posted January 16, 2016 Report Share Posted January 16, 2016 If you go on Brownells uk site and look up shotgun front sights you will see that there are many different threads as well as glue in types. My Ithaca is a 6-48 thread whatever that is, I guess its an American size I think I just got lucky when I ordered a new bead that I got the rght one. The Winchester owners forum would probably have the info too Regards Quote Link to comment Share on other sites More sharing options...
Gunman Posted January 17, 2016 Report Share Posted January 17, 2016 2mm , 2.5.mm , 3mm , are the norms but there are a few oddities especially from the US Quote Link to comment Share on other sites More sharing options...
Cumbrian Posted January 18, 2016 Author Report Share Posted January 18, 2016 Many thanks for the helpful replies. In case the information is of use to anyone else, the drill size for a 2mm tap is 1.6mm, for 2.5mm it's 2.05 < 2.1mm (close enough I daresay for a 2.6mm bead), and for a 3mm tap it is 2.5mm. More equipment buying looks to be in order in my case. Quote Link to comment Share on other sites More sharing options...
fortune Posted January 18, 2016 Report Share Posted January 18, 2016 (edited) 2mm , 2.5.mm , 3mm , are the norms but there are a few oddities especially from the US Are these not the size of the bead and not the thread size. check it out before you drill. you cant put the swarf back in the hole that you just drilled or you could end up with a bead like a golfball. Edited January 18, 2016 by fortune Quote Link to comment Share on other sites More sharing options...
deershooter Posted January 19, 2016 Report Share Posted January 19, 2016 Any one who doesn't know what a 6-40 thread is should not do any home Gunsmithing, it's possibly one of the most used threads on guns most rifle scope bases are held on with this thread. In the end it will be cheaper to go to work ,earn some money and let a professional do the repair I am a very good engineer but I don't call myself a gunsmith Deershooter Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.