This upper came on an AR-10 I bought used a couple years ago. I have no idea how many rounds it's fired, though I'm betting it's at least a couple thousand - regardless, it has functioned flawlessly for the few hundred rounds I've put through it. The scope is Barska's 4-16x50mm with illuminated mil-dot reticle (model AC11002). The windage knob on the scope needs a new o-ring to help keep it from coming loose (it's fallen off a time or two at the range). Be sure to know your Armlite models - this is their AR-10B upper and is not compatible with AR-10A lowers - here's a comparison if you need a refresher: http://308ar.com/AR-10A_VERSUS_ AR-10B.htm Cash only - I'm really not interested in trades at this time.