What causes recoil and noise

[quneur]

I would love to hear his theory on how an internal combustion engine operates.

I asked my friend who has a masters degree in physics; he said, "By magic" and I, who have a bachelors in physics, agree.

 

[charliek]

I'm going out to the garage and put flappers on all my gun barrels, like the exhaust pipes on semi trucks. When the bullet exits the barrel, the flapper slams shut, blocking the vacuum/sucking, and thus eliminating all recoil/noise.
Now, I'm off tomorrow to buy that .458 Win. mag featherweight I've always wanted!