Use one of the following entries with the giveitem self code.

assault_rifle
sniper_rifle
shotgun
pistol
qa_supergun

Note: An example of the qa_supergun code is giveitem self 10 qa_supergun manf_geth_weap this results in a Geth-style pulse rifle with the following stats: 35,000 damage, 35.9 shots before overheating, and 81 accuracy. The manufacturer portion of the code affects the description and stats of the rifle spawned. The appearance does not t seem to vary; all are rendered as a Geth Pulse Rifle. However, damage and other stats can vary significantly. For example, the damage can vary between 30,000 and 40,000, depending on which manufacturer string is used.

The Geth Pulse Rifle, which actually appears to be some type of pulse energy weapon vs. a projectile weapon, is spawned differently than other weapons. Enabling the giveitem self 10 assault_rifle manf_geth weap code works, but does not summon an actual Geth Pulse Rifle, but rather a "generic" assault rifle with the description of a Geth Rifle. The "correct" code is giveitem self 10 gethgun_pulse_player manf_geth_weap which summons the actual "player-legal" Geth Pulse Rifle that your character occasionally picks up late in the game. Note that these rifles do not appear to have mod/upgrade slots. However, if the following code is used, the game will spawn a working pulse rifle with two upgrade slots, with caveats: giveitem self 10 gethgun_pulse manf_geth_weap. The problem with the aforementioned code is that the weapon description will identify it as pistol, even though it is rendered as an assault rifle when you equip it. Furthermore the targeting reticule does not appear to function properly with this particular version of the weapon. Accordingly, it is probably best just to use the gethgun_pulse_player summoning format.