Real Life: Check Your Mechanical Offset
We covered the concept of mechanical offset on your AR-15 here, and showed some real-life damage done when you don't allow for it.
Here's another real-life example from a Marine in Ramadi of what can happen if you are not aware of your mechanical offset (the distance between your sights and your bore):
It took a moment or two before my training overtook my delayed reaction as I thought to myself, “Hey, dumbass. You have a rifle. Now would be a good time to start shooting it!” Through the window of the Opel, I could see muzzle flashes from multiple floors of the buildings on Millions Street. I flipped my M4 off “safe” and rose up to return fire and sighted in. I aimed in on two targets and squeezed the trigger twice, and tiny shards of glass shattered all around me. “Fuck me!” I thought. They were zeroing in on me. However, in my adept aiming technique at the time, I didn’t compensate for the muzzle on my rifle and had inadvertently shot out the side view mirror on the car. That’s what shattered. Friction. "Rookie move," I thought.
Read the rest:
Echo in Ramadi: The Firsthand Story of US Marines in Iraq's Deadliest City by Scott A. Huesing and James Livingston