Make It Rain
From Halopedia, the Halo wiki
It is possible to earn this achievement before earning the rank of Lt. Colonel by going to the armory and finding an item in the inventory that requires that rank. Then, assuming you are a high enough rank to purchase the piece of armor that comes before it, you select purchase and when it prompts you asking if "you're sure you want to buy this," you do as follows:
- Move cursor over yes BUT DO NOT CONFIRM YET
- Now exactly as you confirm yes, push down on the left stick, which would normally move you down the list of armor.
- If your timing was right the game believes that you bought the piece of armor under the one you just purchased.
This will NOT buy the piece of armor that requires the rank of Lt. Colonel, nor will it buy the piece you used to perform this glitch and it will not take your credits, it just gets you the achievement by tricking the game.
- It is very hard to successfully pull this off if you plan to use visor colors, as your glitch may end up buying you a blue visor and not getting the achievement .
- There is a chance that this glitch will not work if your button timings are off.
- There is a similar achievement for purchasing any item in the Armory, known as Make it Drizzle.
- The name of the achievement is a reference to the rap song Make It Rain. The phrase means "to throw money in the air."