Does this look familiar JW?
One of my major goofups was to try to drill a pin hole for the trigger guard lug through the wood and lug at the same on my fowler. My bit hit the lug, went screech and broke off deep in the wood. I tried to drill from the other side and screech, pow, another bit broken off deep in the wood and lug.
The lug was pinned but not in the manner I wanted and never coming off. I hadn't shaped the wood yet plus there was a philips head screw temporarily holding the back of the trigger plate in which is muzzleloader blasphemy.
I shaped the wood with a chisel and piece of sandpaper, it took forever.
A guy on one of the gun building forums said to get a 1/16" carbide bit and put it into in my errant hole with only the weight of the electric drill on it and let it eat. I started seeing metal shavings after about 15 minutes and pow, it made it through lug, eating up the broken drill bit on the way.
I got the trigger guard off, removed the phillips screw, made a new lug as shown above, redrilled and everything was fine.