Was at the range yesterday shooting my .223 LRPV. On one round, after firing, the bolt handle simply would not lift and rotate, allowing the bolt to open. Frozen. After several tries, the bolt opened and the empty was normally extracted and ejected. It happened only once during the range session, and another 25 or so rounds fired, extracted and ejected normally. Could it have been some sort of pressure issue with a rogue round? Shooting factory loads. Thanks guys.