I was fooling around shooting my 280 from the bench this morning. I've been using this load for a few years without any problems. I had fired 3- 3 shot groups everything looked o.k. Fired another round and smoke came out of the receiver vent. The shell ejected a little harder than normal. The primer pocket had a small hole burned through along side the primer and the head was black with soot. When I got home I pressed out the primer and the flash hole was elongated and a channel about 1/64 " was burned into the primer pocket. The primer took normal pressure to punch out. Bad brass or load to hot?