Re: .308 wilson/sinclair trimmer help
I really doubt its the case holder.
Even thou it SHOULD stay the same if you don't adjust the trimmer, I've seen it cut short before when the last batch was dead nuts on. Frankly I have NO idea why. So, that being the case I back it off just a hair for the first one and tweak it, and drive on from there.
I make sure I knock the case into the holder firmly too by tapping it on the arm of my office chair.