We ended up with a delrin track? I never did look at that pole. (errr...poll, I'm not allowed to spell)
Jonny, the model is great and much more accurate than I can do with photoshop pretending I'm on CAD

It needs the taper though. The butt of the gun is 78mm wide and the muzzle is 60mm wide The taper starts 90mm (??) from the butt of the gun. The channels would stop somewhere around the start of the taper. And, can you make it 5mm thicker and put a 15mm or 16mm hole for the bands? Maybe round the nose off?
I know I'm asking a lot Jonny, some of the tasks are easier said than done with cad and 3D, so feel free to tell me to buzz off
