Dear John, <img border="0" alt="[thumbsup]" title="" src="graemlins/bigok.gif" />
I don't want to burst no bubbles "But", As far as I can determine the "Small Arms External Ballistics Co-efficients" were not sufficiently detailed to allow the calculation of the offsets, in the early 1900's, to make a predesigned sight, with ofsets of this type possible.
IMO, All of these type of corrections were worked out in the preproduction tests and were added as changes to correct an observed consistent anomaly in the true flight of the projectile.
it appears that this may be only one of a few weapons that had a feature such as this.
This would indicate a lack of general knowledge of this anomally of external ballistics as being industry wide, and possibility indicate a cut and try engineering approach.
Now, All you guys, I started a Turkey Shoot so, get in line for your shot, I'll Duck if I can.
<img border="0" alt="[icon107]" title="" src="graemlins/icon107.gif" /> ViggoG