Like some of the others I am thinking

Not enough gas
Bolt not having enough clearance
Buffer and or spring too heavy, Creedmoor doesn't have as much recoil as a 308, so does it really need as heavy buffer/spring

Just thinking out loud, but if it is stiff to pull back via charge handle (with or w/o loaded round) and it slams into battery with much force, you may have a spring that is too heavy or something is binding. Note, the AR10 will require more force to pull the BCG back via the charging handle than an AR15.

Have you attempted to remove the spring and buffer to inspect? How about removing the buffer tube? It may very well be a gas issue but your description leads me to believe a mechanical issue with the spring/BCG.

I've talked to my barrel people and they suggest first to try a metal mag instead of the Pmags I have been using. At this point I can lock the bolt back manually but not on an empty mag. It will strip a round from the mag, chamber, fire and eject but not catch on a empty mag. It will continue to strip rounds from mag till empty but not catch on empty. It's working fine except the mag deal, I've ordered a mag from ACS, Ammunition Storage Componets. That is who they recommended. When it comes in I'll try it and post outcome.

Well I finally got the dang thing working, I had suspicions about the gas system. I called the barrel mfg and inquired about the size of the gas port. It's drilled 0.055, a normal .308 is near 0.08 so I drilled it a 1/16th approx 0.0625 I believe. Took it out this afternoon with out doing anything else, same gas block and all parts the same and it came alive!! Fires, strips next round one after another and lock back on empty mag. Just did not have enough gas to move bolt back far enough. With the A2 stock and rifle spring and buffer Hornady 129gr SST felt like a .223 recoil. I'm pumped!

Sweet. Glad you got it figured out!