You said he drilled into the barrel. How could he *not* drill into the barrel if he was enlarging the hole diameter? Then you ask whether the distance from the bottom of the hole to the chamber is safe. Then you show us a hole right into the chamber. I'm confused.
I agree, I think you are confused
A Remington 700 receiver has four 6-48 holes for the base screws. All four of the tapped holes are thru-holes. The forward most hole, closest to the receiver lug, appears to be a blind hole. It appears blind because the barrel is at the bottom of the hole! You don't drill and tap the barrel for that base screw.
The barrel in that area does not normally have a hole drilled into it. It should have unmolested threads on this shank region. With the botched job, the gunsmith drilled a blind hole over the chamber.
Make sense now?
