Actually that joke should be more reserved for typical Hollywood action movies where the guns seem to have unlimited magazines. Or 6 shot revolvers that somehow fire 15 shots. Video games on the other hand these days are pretty spot on due to the amount of research game developers do with gun manufacturers and Military. Hideo Kojima has always been really good at including lots of gun info in his games so even if you don't know squat about guns, you will know about them when you play one of his games.
If you want to make a realistic joke about modern day gun video games, make fun of the stupid regenerating health gimmick. God, how I hate games that do that crap. What happened to the good old days of Wolfenstein 3D or Doom where you had to actually have a thing called skill to avoid being wrecked and had to conserve the health pickups scattered around the level?