have never run into this problem before. Any thoughts?
Yes I do, my thoughts never change. I have the same presses, I have the same dies, there is a chance on occasions I use the same lube. Then there are different dies like the ones other members are trying to get you to purchase. It reminds me of time, there is never enough time to do it correctly the first time but always enough time to do it over or purchase more tools.
If one of my presses does not return the case to minimum length/full length size the shell holder will not make it to the shell holder meaning anything sticking out between the bottom of the die and top of the shell holder did not get shoved into the die. I do not have to chamber a sized case to determine if the case is too long from the shoulder to the case head to allow the bolt to close.
I do not know hat press you are using, I do not know what dies your are using, I do not know what lube your are using. I have choices when choosing a press, die or lube, I have never found it necessary to use small base dies. My small base dies will not size the base of a case, my shell holders prevent the bottom .125" of the case head from being sized, then there is the radius.
I have dies that are mistakes, when I use on of them I get into mortal combat when sizing a case. The die wants to keep the case.
Then there is measuring the case before sizing and again after sizing. I have purchased thousands of cases from a firing range. I have measured the length of the cases before purchasing, my favorite once fired case is a case that has been fired in a trashy old chamber. My favorite cases are cases that are long from the shoulder to the case head.
F. Guffey