Hey guys.
So I’ve just started to Master the Battle Rifle Commendation. At the moment I’m on 171 out of a thousand kills.
I was wondering, do you unlock anything if you Master a weapon, like a weapon skin or something?
With certain commendations you unlock armour sets or visors. Is it the same with weapons? Or do you just get the XP? If anyone has Mastered a weapon it’d be great to know. As far as I know the only way to get weapons skins is through the specializations.
There is nothing you unlock for completing individual weapon commendations. You receive the Protector armor set for completing the commendations for every UNSC loadout weapon.
Sadly no 
You do get extra stances for completing loadout weapon mastery. UNSC ones are Breach and Standoff, Covenant is Standoff and an armour skin (Recon Surge) and Forerunner weapon mastery you get the Believe stance.
There is also an armour skin for completing all the weapon mastery commendations (Protector DRFT).
Seems a bit weird doing weapon commendations and getting stances and armour skins. Should have been weapon skins imho.
Well, if H4’s map structure is the same as all the other Halo’s before it, there are weapon skins in the game. I do remember seeing a Carbine skin during some prelaunch footage.
The only question is how to get it.