I think the die sets are in the top 5 sellers for both of those calibers. .270 has been around a long time & the .308 has been in use for some time by the military & hunters as well.

You'll have no trouble finding bullets for either, brass is common & they both use powders within similar ranges.

Think of it this way....
A .270 is a 30.06 with a smaller bullet.

A .308 is a 30.06 only a little bit shorter.

Make sense?

Frank in Fla