Looking at the instructional video the NFL mandated players view, there are some pretty big hits players can get away with despite the moaning and groaning about the recent wave of fines along with the threat of suspensions.
Some seriously big hits (http://tinyurl.com/2fapcdc).
In a nutshell, proper tackling protocol basically is this - shoulder to the chest of defenseless player good; helmet-to-helmet, helmet or shoulder to the neck or head of defenseless player, fine and/or suspension.
One of the featured don'ts was the Dunta Robinson hit on Eagles receiver DeSean Jackson that knocked both players out last weekend. The Falcons' Robinson is appealing the $50,000 fine.
"As you can say in this play, it's bang-bang," was the narration by NFL disciplinarian Ray Anderson, who metes out the punishment. "But it's illegal."
Robinson caught Jackson with a shoulder to the neck and chin area.