SpudFiles

I have been thinking of making a fifth spud gun but i am not sure about one thing, i have always been using non-modified valves and i heard from someone that if i used a normal one without modification, there will be alot of air pressure lost as it has to travel through the stock, is this true? and if it is, how much enery will be lost?

has to travel thru the stock? you mean in a rifle design? it will lose performance anyway since it needs to go around the bends in the stock, but a modified valve can give you about 2x the opening speed of a standard valve