I had a Sandman-S end cap that blew off, repaired last year. It was a faulty weld according to them. Mailed to them, repaired, and back in my possession in 13 days. I was very impressed with the turn around time and their communication with me.
Hopefully they get yours fixed soon! Good Luck!!
My vote is for the Dead Air Sandman series as well. Particularly the Sandman-S. I currently run it on .223/.556, .300 blackout (both semi-auto and single shot), as well as my 30-30. Just buy the keymo muzzle devices and your good to go.