I was having issues with my New Frontier lowers and Sota Arms uppers and brought them to Element Arms yesterday. It was the first time visiting the store so I didn't know what to expect (thought they might give me a hard time about my choices for lower and upper).
Both rifles would not pass the functions check so they swapped out the upper and lower from their shelf. My upper would pass the test with their lower and so would my lower with their upper. Weird right? The folks at Element decided to replace my FCG and it worked. They ended up replacing both FCG systems on my lowers with a DPMS kit. They also inspected my uppers and fixed a couple things that Sota Arms didn't do correctly. They only charged me $10 bucks for replacing the FCGs and the minor fixes on the uppers ( of course I paid for the kits).
Great customer service! The owner threw in a couple hats for me and my son that was with me. If you need anything to build or upgrade your AR, this place has it!
Richard