Thanks you for the replies. Yes, I was setting the die up incorrectly.
what I have noticed tonight is if I set the die so it touches the shell holder and back it off a 1/4 - 1/2 turn, initially the dies seems to give the shoulder a slightly rounder appearance than when taken straight out of the fl resizing die (as if The case is being compressed). So if I back off a bit more on the die to the point where this roundedness stops, the bullet seating adjustment makes no difference to the overall length and I can't still get near the 2.735'' recommended overall length.
The seating die in the Redding deluxe set is a standard die, not the competition version with the micrometer top.
It has a crimp ring inside. If the die is adjusted too close to the shellholder then the crimp ring will press on the mouth of the case neck and try to crimp it. If your bullet does not have a cannelure for the crimp then the case neck will be forced back, causing the shoulder to be distorted, as you have noticed.
For most rifle ammo a crimp formed this way is not required, nor desirable.
The seating die will never touch the shoulder, I think it is the crimp ring touching the end of the neck that is causing your problem.
The best way to set up a standard seating die is to put an empty case into the shellholder, raise the ram, then screw the die into the press with finger pressure until you feel it snug up onto the case. At this point the crimp ring inside the die is just touching the end of the neck. Now back the die off about 1/4 turn and lock it up. You have now set the die up as low as possible in the press, without causing any crimp.
Now you can set up the seating depth by screwing in the adjuster bit by bit as you seat a bullet, measuring each time.
If you still cannot achieve your desired seating depth with the adjuster screwed all the way in, this suggests the seating plug of your die is not compatible with your chosen bullet. I suppose Redding might be able to supply a longer one.
If you have a complete round which has correct OAL, e.g. a factory round or a dummy (I always keep a dummy round with correct OAL after developing a load) you can set up the seating adjuster almost exactly, first time.
Back off the seating adjuster, put the dummy round in the press and close it, now screw down the seating adjuster until you feel it snug up onto the bullet in the dummy round. It should now be almost exactly correct. If cautious, back it off a fraction of a turn, then make the final adjustment whilst measuring.
In lee Deluxe die sets they supply a special "dead length" seating die which does not have a crimp ring. This die is designed to bottom out against the shellholder, taking up any slop in the press, and meaning it can be fitted and re-fitted without any further adjustment.
You can achieve the same effect with a standard seating die by putting a steel washer or two over the case to take up the gap between the bottom of the die and the shellholder, so that it bottoms out before the crimp ring touches the case mouth. Use the same washer each time and you won't need to adjust the die each time you fit it.
FWIW Lee full length dies are designed with the same principle, they set the shoulder correctly when bottomed out on the (Lee) shellholder. This is an excellent feature, but if used with another manufacturer's shellholder which may be of different thickness it can cause difficulties.
