Beretta Barrel Constriction and Lock Removal

[Harry Collins]

My horrid attorney friend was given a pre war a Beretta SO with an odd bore size and I'm trying to figure out how to translate it. Bottom barrel is .720 with .026 constriction and the top is .724 with .034.

The rear trigger fires the top barrel and is very light. If I shoot it first the gun will often double. I'm hoping the locks are just dirty. I believe the locks are lipped on the front and can be removed by simply removing the rear most screw. Any help here would be greatly appreciated.

Oh, I confess to shooting it under the nose of its owner with spreader loads in the bottom barrel. Few birds escaped this little dream.