The main tube is thick walled aluminium 600mm (24in) long. There is a flange at both ends.

The flange at the back fits onto the barrel before the action is screwed on.

The front flange is a press fit into the tube, then there is a brass nut that fits over the barrel and screws against a nylon washer on the front flange.

All assembly is done with lots of flexible radiator sealant so it is watertight.

The tube is then filled with radiator coolant via a small reservoir just in front of the scope base until it flows out the small hole in the front top of the tube. Both holes are then sealed.

My first attempt leaked a little as I forgot to seal the threads on the front of the barrel under the nut. Now that I fixed that, it is absolutely leakproof.

The base is the same as for my last rail. The base is aluminium and has the standard adjustments required, windage, elevation and a sighter cam. In addition, there is a 1/10 thou dial indicator for windage. This allows me to zero the indicator and shoot my group. If I need to wind a bit of windage for a condition, I can quickly get back to the original position if my condition comes back. I am not sure that I use this too much, but it sure sounds like a good idea to me, particularly in strong mirage.

The action was made with this project in mind (see custom action pics). The barrel is a 1.5" Maddco 6 groove.

On this railgun I shoot a Leupold D series converted to 45X Premier. It has a Swindlehurst converison (like a Tucker) and a Carstensen lock ring at the front lens.