I had an old Epitaph that i wish i still had, was rolled with Solar burn, Performance bonus, Feild Scout/Armor Peircing/Skip Rounds, and Firefly. That combo allowed me to wipe out whole mobs of enemies with one bullet AND i would get ammo back on nearly every kill since PB used to proc with Firefly (Im not sure it does anymore i dont have that beautiful gun anymore to test it) so i could fill my reserves with ammo and just hang back and snipe lol.