JG I don't believe is a pro gunsmith but he's got serious talent. I've seen some of his work and he could make a go of that gunsmithing.
Agreed taking a drill to your barrel chamber is not for the faint of heart.
BUT it does sound like it just needs to be squared up, maybe not even throated too much.
In Memory of Paul "Dietrich" Stines.
Dad: Say something nice to your cousin Shirley
Dietrich: For a fat girl you sure don't sweat much.
Cue sound of Head slap.
RIP Muggsy & TMan
"If you are a warrior legally authorized to carry a weapon and you step outside without that weapon, then you become a sheep, pretending that JOCKO will not come today."