50calty

The flash channel of a Triumph breech plug is indeed 1/8" diameter. I presume the Bone Collector is the same. I am guessing you thought it was 1/16", and started into the flash hole, and it caught. The flash hole is only about 1/8" long so you don't want to remove much material there. If you can't back out the 1/16" drill with a vise grip or some such, you obviously won't be able to use the breech plug.

If it were mine, i would go ahead, and do what i could to remove the drill, and if it broke off, i would install a vent liner. If you aren't comfortable installing a vent liner, mail the breech plug to me if you wish, and i will make it usable for you.

The carbon in the flash channel, when one is using BH209, is so hard it seems like part of the breech plug; it sure fooled me the first time i experienced it; i was positive the flash channel in my Omega breech plug was less than 1/8", until i purchased a new one, and it became obvious the carbon had me thinking it was steel.