I Agree with OWD about carrying the gun around open. This of course would put the wear on the hinge joint & not the bolting.
Unless the gun is very lightly & shoddily constructed I think most of the wear in either the hinge or the bolting does not come about through firing. Most of this wear comes through Friction from rubbing.
Looseness developed from firing would be in the form of springing the frame or compression of the metal in the mating surfaces, not frictional wear.
One thing I think the self openers have going for them is this is a feature normally found only on guns of extremely high quality, thus finely fitted parts. A cheaply constructed gun having the bolting surfaces just milled with no further fitting will "Wear-In" rather quickly as their surfaces are rough. That High Quality finely fitted gun on the other hand has no doubt had these surfaces honed/polished in to a near perfect fit, thus wear is slowed, especially if a bit of lube is applied. That Cheapie is also less apt to be properly lubed.
