The best replacement for smg is steptronic.

The best alternatives to smg are rated as following:
★★★★★  steptronic
★★★★  assault rifle
★★★★  dsg
★★★★  dct
★★★★  6 speed
★★★  shotgun
★★  manual e46 m3
★★  smg ii
★★  pdw
★★  smg2
★★  carbine
★★  jarate
★  dct m3
★  ar black ops
★  machine pistol
★  6spd
★  6 speed m3
★  lmg
  no smg
  manual m3
  6mt
  manual e46
  tiptronic
  micro smg
  global spectrum

Your alternative for smg is not listed? Suggest!
Speaking about smg, one probably shouldn't forget about highest rate of fire.

Other search terms related to smg and their ratings are:
★★★★★ highest rate of fire
You have in mind a companion for smg and it is not yet here? Propose!



Google Trends

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smg
steptronic
assault rifle