I've found the best way to tame one is to agro it to a hill or mountain. Put down a few metal pillars and some foundations above them. Put your canons on the foundations. Aim for the head and it should be pretty easy to dodge the rocks.
For some reason, after the latest update, X-rock elementals (haven't checked other variants) are no longer tameable. Whenever you knock them out, they don't eat and don't have a taming bar. Forcetame also doesn't affect them, so I believe it's a glitch
To tame these turret soakers I’d recommend getting four metal gates 5 pillars 3 ceilings and 3 walls. For the trap and the pillars are supposed to prevent the golems rocks from hitting the cannon. AIM FOR THE HEAD