My AAC Tirant 9mm can blew out of my suppressed AR9 SBR, sending the tube assembly flying while the piston remained on the barrel. I sent it into AAC and in less than a week, they repaired or replaced parts and shipped it back. I can’t tell, but may be a new end cap and brand new piston. They cleaned it up so well, I can’t even tell what’s new and what’s clean and repaired! To boot, they didn’t question why I wet tumbled the tube and it looked like it had been through hell (to remove grill paint), they just refinished the entire can at no charge on top of the rest. Great customer service and all in about one week turn around. +1 AAC