If the rifle is cocked, it is loaded, whether it is loaded or not! I don't need to press check the chamber. A simple rule to live by. I always safety my AR after cocking, no mag or loaded. Just like a Glock, if the trigger is foreward, I consider it loaded. Or a hammer back, it is loaded. Heck, I consider all firearms loaded all the time.
I always thought press checking was stupid. If you have to press check, what were you thinking when you last chambered a live round? Don't you remember what condition you last left your firearm in? Instead of press checking, go through the actions of unloading if you are unsure. If you have to press check in a combat situation, you are dead.