What size drill and tap is required to make your own modified case for use in the Stoney Pt. OAL gauge?

IIRC

I drill - 5/16 -36 Tap

I just retreived my tap from the loading room, and OldGuy is correct - 5/16 by 36 on the tap. I can't locate my drill, and so will have to defer to OldGuys memory. I had to special order both the drill and tap. Stoney Point has done about as much as they can to make this a proprietary product.

quote:

5/16 by 36 on the tap

My adopted uncle Butch Lambert took care of the tap portion of this equation. As always Butch, I am in your dept and will do my best to pay it forward.

I have a Shop Fox on a shelf (Its itty bitty little self is just so cute). I will set this up for drill and tap jobs for a reasonable cost this winter. At that time, I will only need two examples of your 22/378 Weatherby "Wonder Thumper" for you to have a "chamber-all" case ready to go.

Glad to find this out as I need several and have had some time finding them.

to clarify, it is a 5/16 tap drill, NOT a 5/16 bit!! You have to use the correct size for a 5/16 tap.

You can Google "tap drill chart" and have all the numbers there for you.

If in doubt for the 36 thread, use the smaller tap drill, you can always open it up with the next size bit. And that tap is a special order, too.

the best fit I have found is the letter "L" drill. allows for good bite from the tap

It is a 5/16-36 UNS thread. Minor dia is .290-.295 but the 19/64 drill (.2969) will make tapping the soft brass much easier. The threads will be a little flat but considering the application it doesn't matter plus you probably already have this bit.