I don't recall any adjustment screw on the BSE. If you're looking at that phillips screw at the very top breech end of the vent rib, it just holds the rib to the bbl assembly.
I can't think of any other screw in there but they made a number of different series of these with different changes.
The locking wedge is part of the top lever itself. All one part. These are actually 311 actions.
Sometimes the top lever is removed from the action and the hook given a little wack on a lead block to bend it downward a slight amount. That makes it engage the bbl rib extension quicker and in turn brings the lever over 'right of center'.
Sometimes it's done with the lever still in the gun.
It's for looks only anyway. Not a fix, just a cosmetic fix'er up.
If overdone can cause a sticky, hard to open top lever too.
It's a selling point issue and used for resale of guns alot (lever position). It really makes no difference on the guns as long as they are on face, locked up securely and still some take up available in the system when secured.
