After completing a couple of lower assemblies, I am ready for the next step of assembling an upper. I don't reload, yet, so I want a caliber that is readily available. I have enough rifles that cost $1 - $2 per round. I am leaning towards a 7.62 x 39 due to availability of inexpensive ammo. Anybody know where to get a 7.62 x 39 barrel? Bushmaster is out of stock. Olympic assembles lowers in 7.62 x 39, but I cannot find the barrel only on their website. Brownells sells High Standard barrels, but I cannot find a lot specs. on it.