I've got half the answer--after each audience member took out a bullet from the proferred case, P&T each palmed one additional bullet as they put the cases away. After each audience member had written their initials on the bullet itself, P&T each switched the bullet with the initials for the palmed bullet, so that the audience member put their drawings on the shell of a different bullet.
To this end, note how, after the shell drawings were complete, you were never shown the bullets (i.e., the tip of the shell) again, including when the bullets where inserted into the handguns.
So, just as they put the handguns back on stage, here's the situation: each handgun contains a bullet with NO initials on the bullet, and the audience member's drawing on the shell, still on the "proper side of the line".
Now to figure out how they got the bullets themselves across the stage....
I have 2 theories.Atheist version: The audience members mark a bullet that is then palmed, they sign a different casing. Notice how they hold the cartridge so you can't see the bullet while the casing is being marked? P & T now each have 2 cartridges, one with a marked bullet and one with a marked casing. The then walk across the stage and drop the marked bullet down the hollow shaft of the stand while they are tapping the glass to cover the sound. The bullet drops through a small hole in the stage. An assistant under the stage takes the bullets and adds rifle marks and a little sulfur. The assistant takes Penn's bullet and puts it in Tellers mask and vice-versa. They then walk across the stage and put the marked casing in the guns. Notice how the audience member pushes the casing into the chamber without ever seeing the bullet. They walk across the stage again and get the marked bullet and put it in their mouths while putting on their safety equipment. A little drama and a lot of bullshi... er patter and the illusion is complete.Fundamentalist version: They are the Devil!
there doesn't need to be any palming going on. all the stage magic needed here could be performed before the show begins, and we could be shown on camera no less than exactly what happens in the studio.
(hint: it's a gun nut thing.)
oh, and --- whether the trick is based on stage magic or ballistics, it's an impressive show of precision shooting. even with the laser sights, two shooters each hitting a mouth-sized target in such synchrony with the handguns out of their respective lines of sight is no mean feat. the laser dots dancing all over their faces is not deliberately faked, trust me.