Is there a way to make a crab turret that can switch between 3 different guns?

The only way I can think of is that if you make a new slot in the pie menu which is linked to a Lua script that changes your acrab to another acrab equipped with another turret,(while removing the old acrab of course) and spawns it with the same amount of hp.
I've seen this before.

The only backside to this is that i Think that the wounds resets(It will look clean, and I believe that it will reset any lost limbs)?
I think you can specify that it checks for lost limbs?..

I hope this gets you any further, i cant help you with any Lua. I'm bad at it.

Maybe I could have a script attached to the gun that could switch the magazines. The only issues I see is that would not work with "switching" to a grapple gun and I don't know how to change the fire rate/reload with lua.

Very interesting concept of having a Acrab with an grapple gun, it increases the agility of Acrabs immensely.

Well back to topic.
No idea if you can do that with Lua. Fire rate is probably possible though.
If its agility you're looking for then you could always attach a jetpack or a "jump"pack of some sort to the crab. But I guess due to the instability of an Acrab, a jetpack would be very wonky and instable.

The loyalist mod has a tank that switches weapons