Chances are you were being a lot more careful than they were. You wanted your tins back, so you put them back after retrieving the packets. You put the new cartridges in the top of the tins, probably 10 to a side so you can keep track of your rate of fire. How quickly can you get at the bottom 20 if you yank out the tins, throw them away, and tear off the wrapping?
Pine River Boys, Co I, 7th Wisconsin
"We're... Christians, what read the Bible and foller what it says about lovin' your enemies and carin' for them what despitefully use you -- that is, after you've downed 'em good and hard."
-Si Klegg and His Pard Shorty