Head Styles (shapes) on lock bolts

[coutios]

 While looking at many of the new books that have been produced as of late ,the great color photos allow for a much clearer view of small details..  The shape or style of the heads (lock bolts) seem to be as varied as the side plates themselves.. Were these shapes tied to anything? Such as time frame, builder or location  

Thanks in advance

Regards
Dave

[G-Man]

Sometimes.  For example, I have seen a lot of 19th century East Tennessee rifles that used square shoulder bolts with the top edge slightly beveled - this gives it a bit sleeker look when using the square shoulder bolts.  18th century English fowlers I have seen used dome headed bolts.   

[Artificer]

I think Dave's question is excellent and unfortunately I can't answer it

I would also think there could have been/were differences by the country of origin of the tradition of the gun.  How did Germanic vs English vs French traditions lock screw head shapes vary and did we come up with something that was more American?  For Longrifles, did it just boil down to the person who built the rifle and what suited him? 

Gus

[Acer Saccharum]

So many original lock bolts(nails) were lost, and replaced at a later date.

[Dave B]

I have seen no consistant with head style for lock bolts here are some for comparison. These are all versions of a pan head? Some are flat topped some have greater amount of dome to them. Some have a bevel at the edge of the face on the flat face.