You might be pulling the shoulder forward a bit when you withdraw the case from the die.. Take the expander ball out of the sizing die and size a case or 2 and see if it helps. If not, Redding makes s set of shell holders that are shorter incrementally for 6 shell holders but they aint cheap. Or...buy a rcbs #3 shell holder and face off the top with a bench grinder holding it flat on the side until it chambers. My 280 Ackley was build with a wildcat reamer and I had to do this to get brass to chamber after a couple of firings.


Remember: It aint what you shoot...it's how you shoot it.