Would not the proof house keep records of having stamped the gun? I would think a call to them with the information re the gun (particularly serial no., if it has one) and an ask as to the proof marks they stamped on it might yield you the answer you're seeking.
If it were me, I might couch it in terms of "I thought it an odd combination, odd enough that I wanted to know what the proof load was so I might shoot it properly" or some similar line.
I mean, it's not like Boss 20 ga O/U guns are in every corner gunshop....
Last edited by Dave in Maine; 07/28/11 11:59 AM.
