Commando should take at least two to four mobility items, such as Energy Drink, Paul's Goat Hoof, or Wax Quail. These items simply increases his movement speed and keeps him going in the later stages.
Backup Magazines increase the amount of his Phase Rounds. This allows Commando to do more damage with his secondary fire.
Commando can stack Sticky Bombs to do more damage. Since he has high fire rate, he can do more proc damage.
Same reason as above, Commando does lots of proc damage. Tri-Tip Dagger is just perfect for him.
Proc damage.
Proc damage machine.
This equipment is perfect of Commando. He can combo this with his Phase Rounds to do massive damage.