I also looked @ the wssm line and wanted one, but ended up with the grendel. I have talked to people who are smarter than I and look at any reloading data. The AR is designed to function at presures in the 40,000 range. The wssm line runs in the 50,000 range! Yes they do make wssm uppers and I don't know of any problems. Look at the numbers any ways. The 243 wssm 90gr 3000fps, 6.5 grendel 90gr 2850fps. Not much difference plus with the 6.5 BC it wouldn't take long to catch up. Another problem would be barrel life. The grendel runs such low presures it will last forever.
Actually guys, the AR was made to run in the 52,000 CUP/62,000 psi/4,300 bar range, but that's with the 5.56x45mm cartridge. The larger WSSM head size will translate to greater bolt thrust at the same pressures than a 5.56mm, so that's not exactly an apples to apples comparison.
I am building a 6.8mm SPC. I was told it has better long range capability with a flatter flight path than a 5.6 with the punch of a .308
There is an artical about the 6.8 by Shotgunner Magazine..I think.
Normal AR lower is used but a new Bolt and magazine will be needed.
Specialist, sorry, no interest in the 6.8. I have a 7.62x39 upper, and the 6.8 is a .277 and has what seems like only 100 yards or so on the x39. I have a terminal ballistics chart for the .308, 6.8, and the Grendel.
I can hit him man, considering I have shot a total of 10 CF rounds in 5 years, unless that number greatly multiplies, I don't see anything i have wearing out anytime soon. I will take it into consideration though.