I am currently seeking engineering advice on installing a Mercury S hinge bolt in my project Meteor.

The potential pitfall involves the folded metal breech jaws being unable to cope with a bolt being tightened due to there being a gap between the two pieces of folded over steel.
The factory pin fits through all four and the breech block, and as new the hollow gap is not a problem but as is known, can wear and create a wobbly barrel.

I have read John Bowkett welded up the gap then fitted an HW style bolt. I have a Mercury S hinge bolt. To fit this I need to enlarge the outer wall enough to pass the bolt head and nut through then clamp it down on the inner wall compressing it against the breech block for a tight lock up.
Done as I envisage the bolt would be flush against the outside of the jaws as per the Merc S

I wonder whether the inner wall will be strong enough with this set up assuming the outer walls are a good interference fit against the bolt head and nut.

Guidance from the engineering gurus warmly welcomed.