I didn't do any super tags but I drew a Missouri River Breaks Bighorn Ewe tag this year. Also got a pair Bear Paw cow tags. Pronghorn results should be out soon.
I haven't found out yet, although I have the tools to turn necks if necessary. I will be using Hornady brass. I'm hoping a .272 bushing gets me where I need to be.
That's classic over gassing causing too much bolt velocity
It's unlocking before the case shrinks back down after firing. That bends rims and causes the ejector to tear brass. Getting an adjustable gas block or heavier buffer and spring are the steps to correct the issues.
I'd like to give them a try but the plain Custom Comps shoot really well for me. I put down a .124" group at 100 yards last time out with my Creedmoor.
I can't tell you anything about the Lee dies, I've never used them. I do neck size my 6.5 Creedmoor though, I use a 289 bushing in a Redding Type S neck die. It provides plenty of neck tension.
Factory ammo just isn't consistent enough for me. I use Redding Type S neck bushing sizer, RCBS competition seater, and a RCBS full length when necessary.