Late one afternoon, a decent 4 point whitetail buck was walking across a hay field way out yonder. I estimated him at about 400 yards and it was dead calm out. With a dead solid rest, I held the crosshair at the base of his ear and slowly squeezed one off as he steadily walked. At the crack of the rifle, the buck broke into a run, stumbled then crumpled and slid to a stop with snow flying and all four legs kicking. I later measured the distance at 418 paces. I was using my go-to deer rifle, Win M70 XTR Fwt in .270WCF topped with a Leupold M8 6x. The 140gr Accubond handloads chronograph 2936fps average out of the 22" barrel. The bullet smacked him just behind the front leg and blew out the top of his heart, destroyed the lungs and punched out through the ribs on the off side. This was another in a string of one shot deer kills for this .270WCF albeit the furthest shot I've taken on deer. So will a .270WCF work on large deer at 400 yards? With the right load under the right conditions, you bet it will.