This article is from the PEZ candy and PEZ dispensers FAQ, by sharpe@dg-rtp.dg.com (Chris Sharpe) with numerous contributions by others.
Matt Shook initially described this PEZ gun. The description has been
greatly enhanced with the help of several Pezheads.
The materials you need to make a PEZ gun are:
A PEZ dispenser
A spring from a ball-point pen
Double sided tape
A pair of needle-nosed pliers (or wire cutters)
A package of PEZ (ammo)
Choose a dispenser that doesn't have a low neck (eg. a collar, Gonzo's
bowtie, etc.) that might interfere with the projectile. Optionally,
the double-sided tape can be wrapped around the small plastic piece
that normally pushes the PEZ out of the dispenser. The tape serves to
keep the spring around this plastic "pusher" piece, but may not be
necessary depending on how well the spring fits.
The trick is to cut the spring to the correct length. The idea is
that the spring is long enough to fit over the pusher piece and extend
past the bottom of it so that when the head is tilted back it catches
on the plastic of the inner sleave. As the head is tilted back more,
the spring bunches up and finally slips off the plastic of the inner
sleave, striking the end of the PEZ. Instead of the PEZ being pushed
out by the plastic pusher, it is ejected by the spring on the pusher.
The spring mush be short enough so the mechanism will reset itself
when the head is returned to the normal position.
 
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