[cglrcng]

Fancy tubing cutters are nice...a good pr. of diagonal cutters, a 6" section of tubing and a little practice cutting that up into 1/4" sections and a few tips on the angle to hold the cutters perfectly perpendicular to the tube, and in a half hr. you will be an expert. (I personally use and suggest the measure the tube once a bit longer, cut twice method).

Measure it an inch too long, cut fast, then trim it down carefully a bit long....Miss, you can still cut a 1/4" off again if it is a leaker later. Do not make the tubing too short this first time, easiest way to make that run a leaker is to do that.

There are other ideas out there that may work better for your purpose, our bot has a pneumatic catapult of a rather simple but well repeating design, gravity return, no sping action necessary or used there, 3 properly sized cylinders, the right cylinder angle chosen for the pivot point, 1 high pressure tank currently installed, w/ the easy addition if wanted to add 2 more tanks & clips in just minutes, 3 low pressure tanks (all protected inside the bot and not easy to reach into to damage or harm easily), and shoots truss and high goal perfectly static or "on the run", at just 50 PSI set w/ the option to go to 60 PSI, by just dialing up the regulator a bit. We use the newer and smaller/lighter compressor though, for wt. & space savings and faster filling & ease of mounting/replacement if necessary. And 4 12 volt selenoids (3 use single action for those catapult cylinders, in use and 1 uses double action for the 2 open / close type Ball P.U. Cylinders). We are defr not the Ri3D or El Toro type ball P.U..

Oh....And the right programming to make all 3 of those cylinders fire together at the same time. (That is a key to reliable repeatability I'm told).