Just thought I would chime in on this. In the case of forming the 223 short, the case forming is the eaisest part of the whole process. Forming either the 223 or the 221 case is about the same it doesnt take alot of force to form them since I started using LEE sizing wax. Other brands of case lube didnt work good at all, with the LEE lube just a tiny little bit works wonders.
In making up 223 short brass ready to load the first time is time consuming, but if the collet die idea works out well it should be easy after that.
Here is the process I have used to make the brass so far,
Starting with the FL sizing die , remove the neck sizing stem and collet nut, run all your lubed cases thru the die that way, this leaves the long neck.
Cut off excess neck with the mini saw to within .010 of finish size.
De burr the inside of case neck, so trimmer pilot can enter neck.
Run all of the cases thru the case trimmer to finished length.
De burr inside and outside of the neck, lube inside of case neck.
Reinstall the neck sizing stem into the FL die and resize all the cases again, this sizes the inside of the neck to approx. .223 I.D..
At this point you are ready to load them for fire forming, So to end up with a finished fire formed case you have alot of work involved, but with a wildcat you can expect that.