Slow motion gun p0rn:
Some things I took away from this video: the Glock firing confirmed what I had heard previously about the weird ejection pattern that Glocks often have. I had read somewhere from somebody in the firearms industry that slow motion footage shows the empty cases hitting all over the ejection port, making them fly in many different directions. This would be why random cases come back and smack the shooter in the face. Why Glock decided to dicker around with the recoil springs instead of lowering the ejection port on Gen 4 guns is anyone's guess. See how clean the other hadguns throw their cases?
The other thing I noticed can be seen during footage of a shooter firing a full auto battle rifle: the bullet leaves the barrel and recoil shoves the shooter back well before the bolt unlocks, which is why unsupported automatic gunfire (not in a tripod) goes up and to the right. The last time I had to qualify on the M240B, we didn't have a tripod handy, so I had to shoot off the bipods. Getting a passing score was a bitch, even with me putting all my weight into those bipods, and I had to try a couple of times to pass.
More slow motion videos here.