Thread: Where to buy an 8-40 forming tap (or set)

www.brownells.com is a good supplier.
6-48 and 8-40 are the most common sizes for scope base screw holes, 6-40 being the third size but not as common on the modern production.

Originally Posted by Friwi

www.brownells.com is a good supplier.
6-48 and 8-40 are the most common sizes for scope base screw holes, 6-40 being the third size but not as common on the modern production.

Yes, used on firearms in the US and not much else. I think Remington has gone to 8-40 on their Alpha?
GPM.