It seems like another average instructable, so you might wonder: why would anyone vote for this in a contest? You would vote for it not for the complexity, but because it is extremely easy to make, requires no tools, its compact, fits airsoft BBs perfectly, and reloads twice as fast as by hand. Why not reload straight from the ammo can? There are a couple of good reasons:
~ BBs flow out of a pen without blocking eachother
~ you can put up to 15 BBs in a pen, so if you have a 15 round mag or less, you don't have to count when reloading.
~ you can put the pen in smaller openings, like pockets, in your socks, or behind your ear, maximizing your BB loadout
~ if you only have 1 ammo can to split between 2 players, you can each reload with pens
~ if the enemy takes your ammo can, you can still have concealed pens to reload
~ if you put tracers at the top of your pen, they are at the bottom of the mag. Once you fire the tracers, you know you're out of ammo
~ if you spill the ammo can, you lose thousands of bullets. If you spill a pen, you lose at most 15
~ is a friendly using a pistol out of ammo? instead of giving them your entire ammo can, toss them a pen.
~ you can use the cap to empty the mag if you have ammo left in the mag after the game
~ pens are lighter than ammo cans
~ ammo cans take another hand to carry