I have a stag 6.8 spc. I have a problem with it going “click” because of it not putting a round in the chamber and or it going click and having a round in but the bolt is not fully forward and grabbing the round so I have to work the charging handle back and forth until it grabs the round. I am using CProducts 10 rd. mags but it has done this with a couple of those mags.
Most likely bad mag. Try a different brand or a different mag from the same vendor. But it could also be many other things too. The weapon could be short stroking too, I don’t know. But the first place to start is the mag.
Failing to chamber a round may be caused from short stroking. Causes: weak ammo, too heavy buffer spring, gas port too small, leaks in gas system, bad magazines.