Your replies and a visit with my gunsmith gave me a course of action. You are correct, I was bumping the shoulder back too much. The gunsmith also recommended neck sizing only so I ordered a Redding bushing neck die.

While I was waiting for the shop to open this morning to get in to see the gunsmith I measure the diameter of two loaded Lapua cases and was shocked! I started out reloading the 223 with a bunch of misc brass and then bought a few hundred cases of once fired LC brass. When I ordered the set of Redding S-Type dies I measured the diameter of loaded cases and subtracted 0.003" and ordered a .244 bushing. Today I discovered that the Lapua cases measured .250". I had .006" of neck tension. Not only am I bumping the shoulder too far but I'm also working the case neck too hard. I imagine that forcing the expanded neck down to .244" and then forcing a 75gr A-Max deep into the neck is pushing the neck and shoulder down. That means there will be excessive headspace in the chamber. I've now ordered three more bushings including a .248" and a .249" along with some new case lube.

It will take a few weeks for me to know if this solves the problem because I have to wait for the new die and bushings to arrive and then shoot and reload a few more times.
The rifle has been very accurate even with the abused cases and excessive neck tension so I may also see an improvement in the accuracy with the new die and bushings.

I will let you all know.

Thanks for the advice.