When you got the FTF did you recock and try again? ie, did they ever go off?
The neck split on brass that little used is probably a fluke, but your die set could be undersizing the neck a huge amount (not unusual) and the expander ball then pulled through brings it back up to just under bullet dia. This work hardens the brass quickly and splits will become far to frequent. Annealing the necks will help reduce case loss but a die that doesnt undersize so far is the real answer. FWIW, I really like the Lee Collet Neck Size dies (available seperately, you dont have to buy the whole set) and only full length size when I get sticky extraction.
Having the loaded length long should have kept the primer well back to the pin, but if that shoulder was set back you will have to readjust. The factory adj. instructions only work if the chamber and die set both are within SAAMI specs. Im afraid we have a lot of guns (not just handi's) that are chambered overlong.
Adj. your size die up a turn or two, size a case, try it in the chamber & close action. If it wont fully chamber/close, adj. the die down a quarter turn and go through the process again untill it closes. For a while check each case this way before loading them to make sure they all fit. A tad shorter is better than finding out they are mostly a tad too long, loaded and at the range with cartridges that wont fit.