The Birmingham Proof House requires removal of pits prior to re-proof http://www.gunproof.com/Proofing/proofing.html
"Proof regulations require that shotgun barrels shall be 'struck-up' and smooth and that insides shall be clean. Pitting should be removed so far as is practicable, bulges knocked down and dents raised."

If the original bore was .729" it may "still be in proof" if honed to less than .740" (12/1). "Still in proof" does not necessarily establish the integrity of the barrels.


https://sites.google.com/a/damascusknowledge.com/www/home