what would be the minimum metal required between the bottom of 6-48 or 8-40 screw hole and the chamber?

That would depend on the caliber. How much material do you have to work with? The larger the screw, the more material you would want. On a high powered rifle I wouldn't feel comfortable with anything less than .250 if using a number 6 screw.

I had a guy bring a drilled threw into chamber as he was an expert at drilling hole for a scope mount ! Then he expected a fix for $5.00 ! I pointed at the trash can and he left !

quote:

Originally posted by concho:
I had a guy bring a drilled threw into chamber as he was an expert at drilling hole for a scope mount ! Then he expected a fix for $5.00 ! I pointed at the trash can and he left !

Good for you.....anyone fixing that thing is setting himself up for trouble. One could have conceivably threaded that hole all the way to the chamber, inserted a screw and loctited it, and flushed it off inside with a chamber reamer.....

I can pass on a bit that I was given some time ago

the guy told me that two diameters of screw must be left at the bottom of hole when drilling near the chamber and that no holes greater than #8 screw be used.

Not sure where that came from but he said it was his guide and he used it.

I've been lucky as I've never wanted to thread anything anywhere near the chamber.