If he set the water tank on the ground, below the gun, he wouldn't even need a motor to circulate the water. The heat would simply cause it to thermosyphon.I looked at those bores first and was like wtf... Something's off here, I'm seeing diff. Bore sizes. I thought at first all of them were different sizes. Looks like a whole heap of solder I'm there holding the entire bundle together. Looks kinda cracked and splitting a tad too!
How about this one just put out. A water cooled bolt action rail gun! I'm not going to lie, I want it!
Maybe someone can esplain to me though why the water jacket isnt full length? Seems very odd to me. Pretty sure I would have made it full length and soldered it up or silver soldered it for more water tightness.