Have you calculated the volume of your balast chamber and barrel? What I have found is about 1.5 times barrel volume for balast chamber works well. You have more than 3 times your barrel. I figure you have just 2 shots from 1 HPA tank of that size if it will also be regulated down to 90psi like your...

thatguydionysus - I went back and re-read the posts. Aparently I misunderstood your objectives. The semi-auto part of your build is for semi-auto charging and not semi-auto loading. Is that correct?

thatguydionysus - Are you using this valve for fill, main valve for chamber flow, or trigger?
POLAND_SPUD wrote a piece with references you may find usefull. Search "directional control valves".

jsefcik - Prayers are on! My father is carbon copy of your story. Know the signs.

Great work! The high speed recordings make this soooo much nicer to enjoy the hobby...er...obsession maybe. JSR - Do you have any mental reference to pneumatics reaching anywhere near mobile chernobyl's 1500fps + averages. How much influence does kinetic energy have to do with FPS velocities? I mean...

Solar - I have seen Q's MK19, in pictures and video only. If it were in person I may have been tempted to play that trick, "Hey, look over there!" I am on a different path than Q. Whereas he is using an electric motor for his loader, I am aiming for gas blowback. Now I am on the hunt for that PVC be...

Solar - Great info. Since I am scaled up a bit in size from your artwork, I was concerned I wouldn't have enough remote air storage. But now I have to do some more math. My chalk is wearing out.

Solar - Great design. Really refined. What diameter is the main air porting to the revolving cylinder? I understand you have an adjustable velocity, but how many shots are you getting out of the supply air (assuming an average or preferred setting)? I am building a 48mm semi. It will have a longer b...

@JSR - Now looking closer it was about 1 weeks worth of effort and debate.

@Solar - WOW. That Eclipse Launcher is what I have been working towards. Crap! Someone beat me to it. Seriously. Depression is setting in.

My concerns are if people are playing airsoft or paintball on a piece of neighborhood property with their store bought weapons, all is somewhat ok. Official and dedicated facilities have mandated rules with chronographed velocities. However when someone brings in some homemade high power cannon to t...

I have noticed the lapse in activity here. Has anything been developed. Sounds intriguing.

I want this thing to shoot nerf footballs and i want to be able to hit targets that are a loooooonnnnggg way away.

Are there any considerations to milsim gamerules? Because that is where I am running into "issues" in design.

@ madmarcs - are you using this for airsoft / paintball milsim games?

@thatguydionysus - Like you I am building a launcher with similar parameters. I'm trying to find existing components at sensible cost. I have been trying to navigate the forums here, educating myself with what is proven design. I am a machinist, but would rather save my sanity cards and keep from de...

I am working on similar project. Are you doing the machining yourself?