How big can you make a thunderstone?

[Wippit Guud]

I was thinking of catapult-sized thunderstones, creating sonic waves upon impact, knocking people down in a 30ft radius (and doing stome damage to whatever it hit)

Dunno how viable that is, though

 

[AuraSeer]

Under the rules, they can only be made in one size. If you want larger items with stronger effects, you probably want a magic item of some sort.