an automatic term refering to a handgun

[Yournamehere]

I find that the rule is generally, if the letters spell a pronouncable word, it's fair to say it. For example, B.A.R. Spells bar, sounds alright, M.A.C. spells Mac, sounds alright, etc. but two letter abbreviations or ones that have no vowels or something are stupid, like A.K., no one says "ack". Sounds dumb.