Unlike another episode in the past, where they made a smooth-bore 1911 pistol by reaming the rifling out.
Now that right there is against the law!
I remember that episode as well, though I don't recall the type of pistol used. That was to prove a bullet will go straight no matter what you do, though it will tumble end over end without the rifling.
The seem to cover a lot a myths that involve guns. Perhaps America is vastly more into guns that the Brady Campaign would like to admit. It seems like they're shooting something on nearly half their shows such as:
-SKS being set off by loud music (didn't work, though explosives made one of four rifles fire).
-.500 Mag blowing off thumb: plausible; blast from cylinder gap tore through chicken flesh & bone.
-Trying to fire a bullet into the cylinder of the bad guy's revolver. A one in a million type of shot.
-Trying to blow up a propane tank like James Bond, but finding that Bond's 9 mm will merely dent it. A 12 gauge will put a big hole in the front and big dent in the back & a .30-06 will easily blow right through but none will blow it up. They ending up having to get folks with the firepower needed for such an explosion: a heavy machine gun firing incendiary rounds.
-Proving a fired bullet hits the ground at the same time as a dropped bullet.
-Cooking ammo in an oven. Not likely fatal as the casing is fired while the bullet that's much heavier stays there, though a .50 BMG makes a big bang in your oven and probably voids the warranty.
And surely many more I can't think of.