From Halopedia, the Halo wiki
A Long Barrel is a weapon attachment, used to help increase the effective range of a weapon. In gameplay, this manifests as stronger aim magnetism and extended "red reticle range". It generally takes the form of a side-vented muzzle brake, despite its name.
Known Applicable weapons
The following weapons have been known to utilize this attachment:
List of appearances
- Halo 5: Guardians (First appearance)