Looks good, I'd tend to disgree with making the turret bigger as it looks wide enough in proportion terms. A bigger turret wouldn't deal with recoil anyway- that's not a primary function.

You can probably make it look quite complex without too much work so don't despair!

Most turrets work on a hydraulic system on what are basically rotating drums. I attach a photo of a prototype...

Nice, I like the dusty effect. You might want to add something for the turret to rotate on (unless it only fires forward) or a mount to the bottom to make it look more securely attached to the main...

I like the gun. You could take a look at some pics of the Russian 4 wheeled ARV the BRDM or the BRM/BMP for mount ideas as the 'turret' looks a bit small. Depends which you think is more 'extreme'.
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I like the cattle cruncher but coming out an an angle like that will it throw whatever it hits onto the bonnet? Perhaps raise the upper bar to deflect things onto the road? Coming along nicely, I...

Looking good! As Icky said you might try a smaller pattern but that is coming together really well!