I assembled a 6mm ARC gas gun with a 22" barrel last September. I have about 400 rounds of factory ammo on hand for it but haven't shot it yet since I haven't had time to take it out. I have no concerns about the bolts with properly loaded ammo. The same bolt conversation has been thrown about for 6.5 Grendel for years...I have had six ARs in 6.5 Grendel and I've never experienced a broken bolt.
