The ACE family assault rifles are based upon the reliable mechanism of the famous Galil assault rifle. The ACE incorporates enhanced human engineering and ergonomics with the demands of the modern battlefield.
The ACE 21 variant is the carbine variant, firing the 5.56x45mm NATO cartridge, its overall length is 730 mm (Stock Extended) with the barrel length being 215 mm. Much like the ACE 52 CQB it features a composite build, folding equipment and many accessory-rails.
The ACE 21 CQB is a weapon featured in Battlefield 4. As a Carbine, it is available to all classes. It is the carbine version of the ACE 23 assault rifle, thus having the same ROF and recoil. The ACE 21 features a tan paint scheme by default, compared to the ACE 23's straight black paint.
The ACE 21 has a lower muzzle velocity than its assault rifle counterpart, but to balance this, it has a lower spread than the ACE 23 except when ADS and not moving. Functionally, it is almost the same, making it just as popular as its bigger brother. The ACE 21 has a unique ammo capacity of 35 + 1 rounds due to using Galil magazines.
- In Battlefield Hardline, the menu icon of the CAR-556 (ACE 22) shows an ACE 21, and the alpha footage of Sovereign Land's cutscene featured an ACE 21, though it was changed to an ACE 22 in the final game.