Best kill streaks that I remember:
SKS: 30, 34 and 40
C4: 18
Aug A3: 21 (25 on PC vs scrubs).
F2000: 37
M98b and G18 supp: 22
M98b 40 (PC)


...................../´¯/)
....................,/¯../
.................../..../
............./´¯/'...'/´¯¯`·¸
........../'/.../..../......./¨¯\
........('(...´...´.... ¯~/'...')
.........\.................'...../
..........''...\.......... _.·´
............\..............(
..............\.............\...