How can I stop my Phys Asset from fighting itself/ self colliding so hard?

I have a basic cannon mesh here, I’m trying to work out a way to make this a VR asset that I can push around and the wheels turn which I’m almost there but the block at the back of the cannon is supposed to be adjustable so I can set the angle of the cannons trajectory.

So I gave it its own body and set the constraint to prismatic type and limited. This seems to allow for a nice ‘sliding’ type of physics interaction between the body and this block.

The problem is that the bodies are constantly fighting each other and I can’t find a setting to allow for ignoring collisions between bodies. So what happens is that in my scene the cannon just goes wild spinning around and bouncing everywhere.