I think I may have asked this before, but I have the gun, now, from a friend that asked for some help.
This is a Browning O/U Citori based 525 3 bbl (20/28/.410) set.
The .410 barrels work fine. But the 28 and 20 ga barrels are hard to open after an affirmative closing of the barrels or firing. The toplever is sticky and requires a good amount of force to open. Sometimes two hands are required.
My thought is that the bolt is seating too deeply in the underbite of the barrels, and locking into the taper formed by the upper and lower surfaces.
Here's the barrel side view of the underbite (blue arrows).
I believe the bolt should make contact only with the lower surface of the bite, which would pull the barrels down into battery.
The picture of the lower surface of the bite on the .410 barrels shows contact marks of the bolt. (below)
This picture (below) of the upper surface of the .410 barrel bite shows no apparent contact of the bolt.
The picture (below) of the 28 ga barrel bite upper surface shows apparent contace from the bolt.
Before I relieve material off the top surface of the barrels, I'd like some input from any of you that are intimate with Browning locking systems to confirm.
Thanks
