Certain Dillon progressive presses can be notorious for not resizing the full length of the case, unlike other dies.
No press on the market sizes the full length of the case due to the shell holder blocking access to the head of the case. Progressives are even worse because they need more of a lead-in ramp (or internal flare) built into the Sizing Die's mouth. I was not aware that the Dillon
SDB's gave any more or less coverage with their special dies. Due to these inherent design constraints, the Sizing Die needs to come as far down as possible without upsetting the press ram/platen as it raises the shell to the dies.
I would say to check your clearance between the die mouth and shell holder. On all machines, the Sizing Die's position is set first, then all other dies are set relative to that die.
My [Dillon] Square Deal has this issue (compared to the 550/650/1050 you cannot remove the dies and swap them for other brands) so in this case the Lee FCD is invaluable if the bulged cases prevent proper chambering.
If you've got a bulged case after loading, then chances are you had a severely bulged case before you started. Such cases are from guns with unsupported chambers, and not a CZ. So we must be talking about "range pick up brass".
I use range pick up myself, but generally find that under scrutiny, 1 in 10 new pieces are not worthy of reloading. You've got to check for Berdan primers, steel cases, and internally stepped cases, so while it's in your hand why not simply check for this bulging ?
I'm sensitive to your subject, but of the 2
SBD's I've owned, and all the hundreds of
SDB owners I've talked to, you're the first to say this.