"Brass length 2.4925 hornady and reformed 270 is 2.4795"
That seems awfully short for the formed 270 brass even after firing in the Whelen chamber? When I form 35 Whelen from OF 270 brass, I use three steps 30-8mm-35 well lubed inside neck, the formed brass is right at 2.5 inches and needs trimmed to shorten and true up the face/ mouth, trim length is 2.484. Your load of 49.0 grs RL 15 sounds REAL light to me? I think all you are seeing are the remains of a factory crimp left on the mouth and nothing to worry about.