SpudFiles

Ever since I had built my first pneumatic, my friend Alex has been begging for me to make him one. Since I started on a new piston project, I gave in and decided I would make one for him.

The design will be identical to mine in that it is an over-under design with a modded 1" sprinkler valve

However, my question for all the spudders is will using 1.5" piping and elbows for the U bend, be more efficient than the 1.25" pipe and elbows I used for my first pneumatic?

If so, I might just sell him my old one, and use that money to finish up the new one! Hehehe, kinda mean I know. Thank You!

Assuming your valve is after the U-bend, I would personally choose 1.25" pipe due to the fact that the valve can only allow a certain flow, and both pipe sizes exceed that flow. Additionally, the 1.25" pipe has less surface area and slightly less length in the bend for air to lose energy due to friction, as well as energy due to change in direction of flow. Finally, unless your barrel is very long, you will likely make your gun more efficient by using smaller pipe, and thus improving your chamber to barrel ratio.

A chamber larger than the C:B ratio CANNOT decrease the power.

I, honestly, don't think it will matter. I do not believe you will notice a difference either way.

i'd sell him your old one anyway, and use what you learnt in the construction of that to build a better one second time around. it'll teach him to get other people to do his work for him rather than putting a bit of effort into learning how to do it himself.

either pipe diameter will work equally, it makes very little- if any- difference since it's wider than the narrowest point in the chain (the valve)