josebd,
I have never had to do more that neck-size cases in any of my guns. I keep the pressures below maximum on most of my loads (the only exception is a straight walled pistol case). If your cases are expanding beyond chamber dimensions I would look at the load and see if it can be dropped a bit to prevent future problems. To correct your tight fit it might be necessary to "bump the shoulder back" with a full length die.
PaulS