A bit smaller scope and insane rate of fire. M-90 Indra - first sniper rifle that fires in true full-automatic mode.3 shots instead of one - everything needed for dominance.

Black Widow - upgrade of the normal Widow.

Phaeston - Turian assault rifle with great accuracy and stability.

Classic all-around assault rifle that can dissipate heat by its own. When you press the trigger, it shoots 5 bullets in small angle.

Heavy Collector Rifle - brand new weapon, hybrid of rifle and shotgun.

Fewer, but stronger shots makes it better for longer distances.

M-89 Halberd - variant of the Mattock.

However, it holds small amount of ammunition and has significant recoil, so aim wisely! It's just classic AR with stronger bullets.

Cerberus Harrier - full automatic upgrade of the Mattock.

M-25 Hornet - a common Cerberus submachine gun shooting in 3-round bursts with sizeable recoil.

While it doesn't have as high heat capacity as an assault rifle, its cooling rates are much faster.

Collector SMG - rare and deadly self-cooling weapon.

Its rate of fire increases when the trigger is held.

Geth Plasma SMG - fully-automatic geth submachine gun.

N7 Hurricane - despite its lower accuracy, great damage makes it a standard-issue SMG for many soldiers.

It has less countable, but stronger shots. The highest spread in the game doesn't make it effective on distances, but its stun ability definitely compensate it.

M-5 Buck - brand new pistol with shotgun ammo.

Its firepower is similar to standard assault rifle. after completing mission on Freedom's Progress, when you have first occasion to change your loadout). If you import ME2 character you will get all of these weapons instantly (ie. It's because they're balanced to par with better weapons unlocked along with campaign progress. All weapons from MWP are unlocked in few first assignments of the game - pistols after completing recruitment missions on Omega, and everything else after Horizon.

Mass effect 2 weapon upgrades