What the hell is a hybrid SAAMI spec chamber? I bought another AR this week, a Bushmaster Predator. The Specs say that it is a 556/.223 chamber and state that it has a hyrid spec chamber. I fired what I had left of some cheap 556 ammo and had countless FTF and a few FTE's. I had to pull one manually with the charging handle and thats when I noticed how difficult the extraction was. I'm sure that it was over pressure. The Hornady TAP I fired through it functioned flawlessly. Did I get some piece of shit barrel?