What would you like to know about the 6x45 aka 6mm/223 I have owned a few for almost 15 years.
It is a poor mans introduction to wildcats.
Velocity is higher with the same weight bullet of a 223 because of increased case volume, decrease in bearing surface and an increase in pushable surface area.
Energy at the same velocity is about a 30% gain over a standard 223 round.

You can legally hunt with this cartridge. It is great in deer/pronghorn rifle out to about 300 yards.

The best part is all the parts stay the same in the AR with just a barrel swap... even mags are the same!

BTW if you need load data I can hook you up with published data.