This is nothing but a myth.
|“||A lookalike variant of the M4A1 made to resemble an airsoft gun. Don't be fooled by its orange tip because this is the real steel!||”|
|— The Arsenal|
The SD Gun is an assault rifle found within the game's files. It is currently not available in game, and whether or not it will be released remains to be seen.
Nothing is known about the gun as only its stats, texture and model files are found within the Combat Arms files. Its stats are similar to the M4A1. Also, the gun resembles a M4A1 Desert Warrior with a compressed/shortened barrel and adjustable stock, albeit the orange barrel tip. It is thought to be an airsoft gun.
- The model files for this weapon were found a while ago but were removed from the Leaked Content page. Statistics for this weapon were later found in the .REZ files.