My AyA 4/53 28 ga had barrels that diverged. It was sent to Briley's to have thin wall choke installed to correct the issue, which it did. My 12ga 4/53 has been rock solid for years now. I had Briley thin wall chokes installed in the 12 ga also to permit the use of steel shot when it was required.

I purchased both some years ago and I am very satisfied with them.