Just as a note if one does a side x side comparsion of early production Lefevers (thumb push & side pivot) vs late model Lefevers (Two hook & single hook) it becomes "Extremely Obvious" that those early guns had far more "Adjustable" features than later ones. There is not a single adjustment on a later large hook gun which was not present on a thumb push, but the reverse is not true.
As to the bolting it is noted the bolting on a Lefever is placed at max distance from the hinge so excellat mechanical advantage ls obtained. On thumb push, side pivot & early two hook guns the bolt entered the rib notch from the rear & these guns had a screw through the top tang which adjusted the bolt downard for wear. With the introduction of the central pivot lever the bolt was attached as an extension of the lever & rotated into the notch from the left side. The lower (bolting) surface of these guns is cut on a 15° angle & are thus self compensating with the lever coming further around to adjust for wear. It is I think worth noting the ball hinge should only be adjusted if necessary to take up its own wear. The main forces on a break open gun are in line with the bore axis which tends to spring the standing breech back from the bbls. Both Dan Lefever & W W Greener stated that an ordinary break action dbl could be fired with no dire consequences with the bolt/s completently removed & the gun kept shut by the action of wrapping ones thumb over the bbl breech. The square shoulders of the Lefever Doll's Head are a quite effective metrhod of adding support to the top of the breech to offset this flexing action of the standing breech. If the ball screw is adjusted in order to bring the lever back to center the bbls are pushed back & consequently up as they contact the standing breech earlier thus losing a lot of the contact of those shoulders in their socket. As long as the bbls are seated properly against the standing breech & the gun is securely bolted the position of the top lever is purely cosmetic, it should be allowed to come around for its intended purpose.
I might note I have an H "Parts" gun which has a crack in the left bbl (twist) very pitted bores & appears to have had much use. The ball screw had been moved when I got it. On a lark I completely removed it & re-assembled the gun. The Doll's Head & Bolt combined snugged the bbls & breech together quite tight with the lever just left of center with a lot of wear still left in the bolt. With the forend than snapped on there was virtually no detectable movement unless enough upward pressure was exerted on the bbl to raise them from the bar. "IF" I tighten the ball screw enough to bring the top lever to right of center there is then a visable gap between the shoulders of the Doll's Head & the mating frame shoulders. Overall a very effective design I think if used appropriatly.
