Can chokes be opened by shooting over many years?

[Double Lab]

Shooting even a gadzillion loads through a gun will not "wear out" the chokes. Is this gun still on face Tom? That would wear first.

To establish the "choke" for the gun you would have to take the choke diameter then subtract it from the bore diameter and then pattern it on paper. Remember that the loads that the gun was patterned with are vastly different from the loads commercially available today. Unless you reload with fiber, filler or overshot wads the plastic shotcups and modern powders that most of us use are going to give you a totally different result. And yes the Galazan type plug gauge only measures the very end of the muzzle and they can be way off.

Best advice is to take it out and shoot some targets with it Tom. The proof is in the pudding. If it breaks targets hard on the skeet field then you got choke. If not someone has reamed the chokes. We don't live that far from each other Tom, contact me and I'd be happy to measure the gun for you and just maybe we could shoot a few targets just for the fun of it.