MA3A assault rifle
From Halopedia, the Halo wiki
The MA3B Assault Rifle is an older variant of the MA5B Assault Rifle used by the Marines of the UNSC. These weapons were obsolete when the MA5B was produced, as the MA5B was capable of being stripped down or reconfigured in different ways for various missions. The MA5B could become an MA2B Assault Rifle when its excess components were removed.
As of 2552, these weapons were in the black market. They were used by the Eridanus Rebels for security of Eridanus Secundus. When Spartan-117 returned to the base, the guards were using MA3B's, which replaced the HMG-38 Rifle model they had previously used.
