I doubt that's actually the cause, if this is a new rifle straight out of the box what probably happenened is what's known as "tolerance stacking" The cam pin specs are X +/- .003" for example (I have no idea what the actual cam pin specs are), you get one at +.003" which is still within specs, but then the parkerizing goes on a bit too thick, and now your cam pin is +.005". End result is that when the cam pin stops it's rotation in the BCG as you pull back on the charging handle, your bolt is not completely unlocked yet. One of the reasons I asked about the gas key being securely attached. Just for $h!t$ and giggles, if you can get the BCG out try swapping just the cam pin from your other rifle. You could also try rotating the current cam pin 180 degrees and see if it improves things for you.