Does this seem right?

[Gun Freak]

I am designing and airsoft gun and GGDT seems to be giving very good results, higher than I expected...

[clemsonguy1125]

Hmm, Are you using a QEV or homemade barrel sealing valve

[Gun Freak]

I wish you would stop asking me these questions, lol its a homemade piston valve... Not project x anymore I guess haha

[clemsonguy1125]

Darnet, I was so close to guessing what project x was, I thought a QEV semi auto airsoft gun

[jrrdw]

ID '0'. Flow Coef '45%'. Are you sure those numbers are right?

[Gun Freak]

ID '0'. Flow Coef '45%'. Are you sure those numbers are right?

I normally leave the flow Coef alone, it is hard to know what it really is. The chamber data is right. The OD is actually the ID of the chamber and the ID is what you put as zero.

From GGDT website:

Reservoir -> Outer Diameter
GGDT assumes that the reservoir is a right cylinder with a longitudinal void in it. The outer diameter input corresponds to the outer diameter of the reservoir cylinder. Note that we are talking about the outer diameter of the air volume, not the outer diameter of the piece of pipe you might use to actually make such a reservoir; it is instead the inner diameter of that pipe (which defines the outer diameter of the reservoir volume). Clear as mud?

[SpudBlaster15]

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[Gun Freak]

Looks about right. Even though the chamber pressure is low, you're using a piston valve with VERY overkill flow, a 36" barrel, and lightweight projectiles. 660fps with a .12g airsoft round isn't exactly difficult to achieve.

Cool, then I guess my gun will be pretty good for airsoft wars The volume was what I was looking at, only 3 inches long... That is the smallest piston valve I can easily build so I don't care if it is overkill cause that valve only costs about 5 bucks to make.