Do not waste your resourses on a canon becouse its a lot harder do hit it in hes fase so make a rocketloucher its a lot ezierer to hit a rockgolem is hos face.
Rock Elemental
The Rock Elemental is a massive rock monster that is typically found disguised as a stone formation. When a survivor enters its territory, it will begin thrashing and throwing large boulders. Once tamed, it can be a highly effective siege weapon to bring into battle.

How ARK players tame and knock out the Rock Elemental: what to feed it, what to knock it out with, and how to keep it safe.
Tamed a 120 with stone
Im one crazy ark player aint I ?
Put a metal foundation and on one side 6 metal doorframes high, extend that side of the foundation with 2 thatch ones en the 3rd again a metal one with 6 metal doorframes high so you can aim your cannon but the doorframes block the incoming boulders, for safety put metal pilars…
Put a metal foundation and on one side 6 metal doorframes high, extend that side of the foundation with 2 thatch ones en the 3rd again a metal one with 6 metal doorframes high so you can aim your cannon but the doorframes block the incoming boulders, for safety put metal pilars 4 high on each side of the last foundation, make sure where u build your 'U' trap, that you have a clear shot, this safes you from a lot of metal runs for fixing your cannon