Another mech Ion

[tyronejk]

This project started as a pile of parts from previous projects that seemed to need just a few bucks in more parts to build another complete gun, so why not? (This was much more than a "few bucks" in parts.)

Initial mockup. My plan was to make a spacer/volumizer to fill this gap between the stock breech and firing can. The spacing is meant to line up the gripframe holes in the Ion body to the holes in the PMR UL frame below.


Figuring out where parts could fit in the gripframe. This is when I was planning some fancy dump chamber shut-off to allow the use of tail-less bolt (e.g. TechT L7), which would let me just chop a stock bolt in half and net me:
1) increased dump chamber volume and reduced operating pressure
2) increased forward bolt force to compensate for the reduced pressure from adding a volumizer

The parts in this picture are an air-pilot actuator threaded onto an NC valve (both from Clippard) and just a 10-32 tee fitting.



Got 3D-printing grip panels (printed from elastomer). I integrated a mount for the SMAV-3 here.


Testing hose connections. The piloted dump chamber shut-off system worked, but also vented a significant amount of air from the pilot valve each time.


Realizing there's no way I'm gonna fit all this in the gripframe:


Going the easy route with a extended bolt to match the increased length of the volumizer.


In progress: making a 90 deg barb fitting for the SMAV-3 to route a hose to it without kinking it.

[JeeperCreeper]

Interesting. Are you hoping for better efficiency?

[tyronejk]

No, not specifically.

If you're referring to the volumizer/spacer, that's just to get the grip frame holes to line up between the Ion body and the UL frame.

If you're referring to the weird Clippard shutoff system, that was originally planned to avoid having to make an extra long bolt tail.

[JeeperCreeper]

Ah I see now. I was just thinking the extra volume would probably need lower pressure to fire at velocity. Either way this is an awesome build.

[tyronejk]

Oh yeah, I think it should run at a lower velocity with the extra volume. I'm not sure if that will help or hurt efficiency. The flow path through the extended firing chamber is somewhat restricted, which wouldn't help.

[powpowpaintball]

I've always loved the ULd ions, and this one being stretched makes it even sweeter. Did you make the volumizer/spacer from scratch or is it a cut down Ion breech?

[tyronejk]

The volumizer is made totally from scratch. Just regular old 6061 aluminum.

[tyronejk]

Here's the 90 deg barb fitting for the SMAV-3. It looks funny because I have only a lathe and no mill and didn't bother trimming off the excess material.


And completed gun! It actually worked the first time I put it together except for a couple minor leaks, but I had to take it back apart to install the ball detents anyway.


I'm curious what the operating pressure is now. I'll test it the next time I'm at the field.

[tyronejk]

I took this gun out to the field this past weekend and was able to test it fully. It's sitting right at 160 psi shooting in the mid 280s through a slight underbore Freak barrel. I didn't notice any consistency issues with higher ROF (~8ish) despite the lower pressure and lack of QEV.

[tyronejk]

Yep, that seems to be the case. The usual logic for using a QEV in mech Ions for consistency and avoiding short-stroking doesn't seem to hold water.

[BrickHaus]

I can say, with my double ion the bolts cycled too slow with 0 and or 1 qevs. I could not hit velocity at 180 psi.

With a qev on both shooters it works, but I forget where my pressure is today.

[Jordan]

I found QEVs worked more as an antichop feature on my mechs... and if my line was a bit kinked it covered for my installation booboo.