There IS published data for a 240 gr. bullet in a 44-40, I found it at
www.loaddata.com listed under Lee data. Yes, it is for a 240 gr. lead bullet, but their starting load is 6.1 gr. of Unique, so Doug load was nowhere near excessive. Doug I think you were reasonably prudent using .44 Special data as it is a cartridge case of lesser capacity. Everyone jumped to the conclusion that the case separated due to pressure issues, but if you understand basic internal ballistics, that's not likely. Had he loaded 7 or 8 grs., maybe, but not with the load he used.
Doug I had the same thing happen with a .303 British (using light cast bullet loads, FWIW). I removed the seperated portion of the case by running a tight batch down the bore, stopping it just ahead of the mouth of the case. I then melted some Cerrosafe and poured it in from the chamber end. The Cerrosafe filled the voids around the separated case and allowed me to tap the patch, Cerrosafe and case out, all in one piece. Pretty easy, actually.
Hope this helps.
CHT