A good number of airsoft players around the world always go for US military impressions for reasons the US military is the most combat in combat amongst nations with standing armies. With the full brunt of media and internet, all their gear are explained in great detail, and for militaria fans and soldier wannabes, these are a gold mine for creating the military impression.

For airsoft players and reenactors, it's not only the gear that counts in that impression, but sometimes the swagger and the physical look which in this recent times, the Tactical Beard has been at the forefront with the rise of the Tactical Beard Owners Club (TBOC). But even that will not be enough for many that even the military terminologies, and most importantly, the military slang should also be remembered.

Honestly, I don't know most of them, just some basics, such as the "Sandbox", "IED", "Fast Movers" "Greenzone", "Embed", "Dustoff", and a few more. Before we mainly know "MRE", "GI", and of course the alphonetic radio communications which is very much mandatory if you are to use a radio. But this new glossary of U.S. Military Slang shows a good list of terms that I do know about, and you and I might as well learn about these if we were to do a U.S. Military impression.

Here are some examples:

Moon Dust: The powdery, flour-like dust that covers everything in southern Afghanistan and much of Iraq.
Ranger Pudding: A field-expedient Nilla Wafer made from MRE ingredients. Mix a paste of creamer, sugar and water, apply to a cracker. A chocolate version is possible if cocoa powder is available.

Self-Licking Ice Cream Cone: A military doctrine or political process that appears to exist in order to justify its own existence, often producing irrelevant indicators of its own success. For example, continually releasing figures on the amount of Taliban weapons seized, as if there were a finite supply of such weapons. While seizing the weapons, soldiers raid Afghan villages, enraging the residents and legitimizing the Taliban's cause.

Secret Squirrel: Highly classified, Top Secret. Secrecy confers tremendous status upon soldiers — the most classified missions are often the most prestigious in soldiers' eyes

TIC: (pronounced tick) Troops In Contact. Usually means a firefight, but can refer to an IED or suicide attack.

If you know all of the aboe you either have already made your own compilation or a veteran of recent operational theatres for the U.S. Military. 

You still want some more, visit the The definitive glossary of modern US military slang at Global Post. For now, I will have to visit a Green Bean to get a cup and try to memorize these. There are more, but you will need to google them.