Which plug size?

If you read my other thread, you'll know that my M94 was a hole in the barrel that needs to be plugged. I see that Brownells has different size plugs but I'm not sure which one to use. 6-48? 6-40? 8-40? Is there some way to tell for sure?

Thanks

go to a good hardware store ask for the machine screws try them till you find the correct size. then right it down and order them later from brownells.

good luck,
Bull

You won't find any gun thread screws at a hardware store.

6-32, 6-40, 8-32, and 8-36 are common hardware store machine screw sizes.

6-48 & 8-40 are only used on guns.

If you have some way to measure, like a dial caliper?
Or a number drill bit set?

A 6-48 screw hole is drilled with a #32 drill bit = .116".
A 8-40 screw hole is drilled with a #28 drill bit = .1405".

rc

I have a dial caliper so I guess I can measure the diameter that way but what about the thread pitch? I do have the screws from the bases; I just don't know what size they are. Can I just count the threads? Though if the diameter is .116" I guess it must be 6-48 and if it's .1405" it must be 8-40, yes?

BTW I can't use the screw from the bases to plug the hole either because the offending hole is just in front of the rear sight dovetail and it sticks up far enough to interfere with the rear sight. Nice piece of gunsmithing I have to work with here. :banghead:

EDIT:

I measured a screw and it came out to .135", which is a #6 screw. Also found that 6-48 is a standard scope base mounting screw size, so I'm just going to assume that it is a 6-48 and buy my plugs accordingly.

Thank you everybody for your help.