Originally Posted By innocent_bystander:
I think your step down bit leaves a flat for the swivel head to sit on.
After drilling a pilot hole you could countersink the hole so the swivel head sits more flush with the stock.
Gotcha. IIRC some of the synthetic stocks already have a flat spot molded in for the stud –– as long as you drill perp. to that I suppose the step-down would be completely unnecessary.