The Crushed Gold blank is so brittle (to me) that the care I exercised still resulted in some chipping at the left end of the blank when turning. Repair was made using superglue to fill the chipped portion and re-sanding the blank. Chipping also occurred when I was sanding/polishing the blank at the ends.
On the cracking of the completed barrel when pressing in the hardware, my reflection of what I did reminded me of a couple of videos I watched on YouTube. The videos showed them using a sanding disc of sort in the chuck of the lathe and a transfer punch about the size of the ID of the tube in the tailstock chuck. The blank is inserted into the transfer punch which acts as a guide. When the blank is presented to the sanding disc held in the headstock, will have to be square (or very close to square) to the sanding disc. This setup would produce a square face (on the blank) relative to the tube in the blank.
My setuo, not wanting to dig out a piece of aluminum to make the sanding disc: