What is the difference between 5AN drumsticks and 5A drumsticks?
5AN drumsticks have a nylon tip whereas 5A drumsticks do not.
I use almost exclusively 1A drumsticks. Drumstick sizes vary between manufacturers, but Vic Firth's 1As are slightly thicker (.565" vs. .580") and significantly longer (16" vs. 16 13/16") than your standard 5A drumstick. I'm sure at some point in the past drumstick sizing nomenclature made some sort of sense, but with all of the different varieties and naming conventions you kind of just have to test to see which you like best.