To me, they r the best ammo upgrade in the entire game. They slow ur rate of fire about 40 percent but increases ur damage by 24 percent. Now if u use ur cram rail and rail extension upgrade, ur gun and pwn everything in a couple of shots. the rate of fire decreasion slows ur gun down so u never over heat. It fires slow enough so u wont over heat, but it is power ful enough to take anything down. I would only advise the snowblind rounds for the assualt rifle tho.

If you just put two Friction less matireals on them and incenrate rounds you can shoot for ever withought overheating on you sniper and you do more dmg but i usaly just go for the one hit kill with the exsplosion rounds

Toward the end, my garrus was owning everything with the sniper rifle. I would zoom into a geth, and watch him fly across the screen as he takes em out lol. That works ok!