| M4A1-C-Red Crystal has a red dot sight, silencer and improved butt plate. The weapon's skin is translucent red crystal for higher collectible value.|
- Weapon description
M4A1-Custom Red Crystal still has the original M4A1-Custom features and it has a translucent red crystal skin. It is equipped with additional ammunition capacity (+5), a silencer and red-dot-sight scope.
In some versions, it also allows to see through smoke and has an even larger magazine capacity (+8).
- Moderate high damage dealing.
- High accuracy.
- Medium rate of fire.
- Usable red dot sight.
- Higher accuracy when using red dot sight.
- Loses accuracy when sprayed for too long.
- Slow rate of fire when using red dot sight.
- CF China
- CF Vietnam
- CF Philippines
- CF Indonesia
- CF North America
- CF Europe
- CF Brazil
- CF Español
- CF South Korea
- This weapon uses the new model of M4A1-Custom, but the red dot sight cover has been removed.
- The description in CrossFire Vietnam claims that M4A1-Custom Red Crystal has 38/76, but it actually has only 35/70.
- This ammo capacity is used correctly in CrossFire North America.
- This gun has inconsistency ammo capacity in CrossFire Vietnam.
- In CrossFire North America description, it says "high quality silencer" however, it is not true since the gun uses the original M4A1 firing sound instead of the silenced one. The reason is unknown.
- This glitch has been fixed in a recent patch.
- CrossFire Indonesia released this weapon as an event item for the winner of regional-national tournament.
- In CrossFire Philippines, this gun has full wallbang feature.
- After the removal of Point Mall, this weapon is removed and placed in the Mileage Shop.