SpudFiles

Hi,

I have a pen gun with a barrel sealing piston (okay, not really a "pen"... more like a fat marker). I tried punching in the numbers for GGDT, but there are inputs I'm not quite sure about...

I made a diagram with the sizes and diameters I know in the jpeg below. I'm wondering what GGDT will say about my barrel length.

I'd appreciate it if someone could crunch the numbers and show a screenshot of GGDT? I promise to make a fun damage video when the marker gun is done :blackeye:

Here you go, not the most impressive performance in the world but pneumatics, even HPA ones, tend to prefer long barrels for that to be the case.
If for example I keep all parameters equal but increase barrel length to 10 inches, I get 9 ft-lbs of energy, double of the current configuration.

Hey! Thanks JSR. Glad you saw my distress call. I made the barrel length 8" and narrowed the bore to 0.25". This is the new specs I believe. It's shooting nails through wood real nice now

Sorry for the late reply, but glad you made it in the end did you post the finished project?

Not yet. I'll do that soon, hopefully with a video too.