It is somewhat of a mystery why these rounds will not chamber but you may be on to something with the short throat theory. I think I read something about this on another thread.
The few handloads I did had a OAL of 2.828 using SMK 168 gr. bullets. The Sierra book says 2.800 so I think the bullet is seated about normal. I am somewhat new to all this so still learning and do appreciate the info.