Potential serious issue, bought new, seemed floating front grip was a little loose. Tightened ring on double jam nut and I thought OK. Fired 10 rounds and front grip loose again and rifle would no longer fire. Discovered barrel had also become loose. Dangerous ! Completely removed grip, gas block and tube and jam nut. Threads looked OK, reassembled and all seemed tight and OK. 4 rounds and barrel loose again. Took to local AR shop and was told he had seen 3 other 2va-15's with same issue in last few weeks. Replaced 2va grip and nut with all steel parts from BACK and resolved. Also having a short cycle issue I'm trying to figure out, ejects spent brass fine but bolt not going far enough back to pick up round most of the time.