It takes three tools to make a nail hole in 5/16 material.
Stamp, Drift Pritchel.
The stamp is driven in first and creates the portion of the hole for the nailhead.
Two to three hits are enough.
Run the frog eye over the horn then restamp lightly to clean hole up.
The drift forms the portion of the hole for the nail shank.
Lightly bottom the drift in the hole.
This will reduce the slug that will be sheared by the pritchel to 1/16.
Pritchel at a black heat.
Hope this helps!