I always think of this video.

That's the video I always think of too. I saw it 20 years and it's lesson saved me a few times as I was a cop for 9 years. A friend of mine used open hand against a 7" kitchen knife one day to create distance then got of a double tap one round hit the suspect leg other hit the abdomen. 21 foot rule to me it's 30.

The 21 foot rule is generally accepted as a proven concept with LE, military, and correctional circles. I personally don't want to challenge it in a live fire scenario, nor do I want to what if this to death. i will say that the "21 foot" concept would definitely be a weapon in the arsenal of my attorney should it come to that. the point I guess is to remember that you are responsible for your actions, and the ability of you and your attorney to explain these actions can be crucial. As far as carrying a knife, absolutely and always! have you ever tried to cut a seat belt or a piece of string or open a can of copenhagen with a glock?