Knockback

Ability of weapon to knock down and push over ground your target.

The following weapons have Knockback perk:

• Super Sledge
• Sledgehammer
• Louisville Slugger

The following weapons can Knockback enemies due to their type of damage (explosive):

• Grenade (Frag)
• Rocket Launcher

What's the difference?

• First ones' knockcback can be occasionally triggered on critical hit only.
• Second ones' knockcback can be occasionally triggered on any hit. Also they usually knockdown target independent of whether was it critical hit or not.