Primary Weapon:
Fires sound, not bullets. "Projectile" is slightly larger than Pyro's airblast, with slightly more range.
Deals 75 damage at point-blank, and 40 damage at outer reach.

+Attacks knock back targets.
*Applies similar knock-back to Engineer.
+Attack hits every target in range.
- -50% max ammo
- -4 ammo loaded.

***

The numbers will probably require major adjustment, but the basic concept is a weapon with two primary uses:
1. Keeping attackers away from buildings/knocking them into range of sentries
2. Providing Engineer additional mobility options, allowing for more creative sentry spots.

I don't play a lot of Engineer, so I've no clue how this stacks compared to his other primary options. Feedback is appreciated!