Originally Posted By: L. Brown
Maybe the tubes were proofed earlier, then the PJ mark added when the entire gun underwent finished proof. Another one of those mysteries.


Crossed lightning bolt proof mark is applied to guns proofed in a finished state, so that doesn't seem to be the case. In that era, it wasn't uncommon for makers to procure barrels from a different source, rather than produce them in house. Maybe provisional proof had to be applied to raw tubes.

Best,
Ted