While I don't have a Stag- 10 yet (gratuitous plug: would love to win the one our Club has on raffle!) I have used the 168 gr A-Max well out to 600m in my XCR-M. I use H4895 and cci primers. Rifle shoots .75MOA consistently.
If you are willing to invest the time (excluding the installation of a premium barrel) there is no reason you can't make your semi shoot very well! I can probably even tighten up this group more but at the time of load development I was doing this and 2 other ELR rifles so I left this one as is. Obviously the downfall of the semi platform is that you will be limited to COAL by the magazine.
A Lee factory crimp die works well and once set up probably will give you the best crimp consistency.. I have found their collet die to really work well (and prefer it over a dedicated crimp die in this case) as there is often no real need for a "crimp" on these style bullets and the neck tension is enough to keep the bullet firmly in place given the mild recoil of a .308.
Don't dismiss the ability of any semi... given a little bit of time and effort they will surprise you!