Oh yes, it is. It can take any hit (with no boosted stats by the opponent) with the assault vest. Also, with No Guard, Dynamic Punch is a must. Here is the set I use on Pokemon Showdown for my amazing machamp:
Trait: No Guard
EVs: 252 Atk, 252 Def, 4 Spd
Dynamic Punch: STAB, hits every time, 100% confusion
Stone Edge: Covers Flying weakness
Bullet Punch: Priority, covers Fairy weakness
Knock Off: "Knocks Off" foes item, demolishing their strategy
Hope I helped!