Has it really been a month? Gosh I'm slow to respond. Thanks John, that does help! If I'm remembering how to do my math right, that would result in a 1.2% peripheral squeeze. Is that enough to still seal up to around 100psi? The specs I'm looking at recommended a 5% peripheral squeeze. What I'm comp...

Thanks guys! I eventually found them at an auto parts retailer. I found some solid core stuff too; though sadly the ID was a little larger than I hoped it would be (2.047"). Maybe someday I'll run my own tests on what foam core can handle before bursting. I kinda just want to blow up some pipe

Looks slick tech, nice work. Any chance you measured those o-ring IDs and Widths? I want to be able to calculate your perphral squeeze % to figure out which rings I should buy

Hey tech, I've been doing some research since my pistons didn't seat this morning and it seems like in order for the ring to seal, the OD of the ring has to in fact be larger than the ID of the chamber bore. In technical designs, there is even a "Concentricity" measurement, being "a Total Indicator ...

Slight necro, but its important to point out that in legal terms "firearm silencers" is an extremely broad term that applies to anything that could be used to silence a firearm, including even something that is built into a spud gun. Be careful if ya do go working with silencers as if I remember rig...

Anyone happen to know any pressure-specs about foam core pvc? If the anticipated burst pressure is high enough, it might still be safe for use in my application. I want to 3" pvc for my chamber, but the local store only seems to have the foam-core stuff. I only intend to run on about 30 psi of press...

Tech, I would assume that the O-ring is 2.5" OD, so really all we need to figure out the part number is the thickness. For my 2" piston design I actually bought 3 different to play with different pistons: -032, -133, and -224-- .07, .103, and .139 respectively. I don't really have any tools per say ...

The QDV design I'm working on currently extends the chamber along the full length of the barrel. Not much of a modification, but it would make the total outer diameter about 1.5". You could potentially craft something that at least appears to function similar to the Australian metalstorm weapon syst...

So this is what you've been working on! looking good man, I'm impressed how well that rust is coming off--hopefully it didn't decrease the structural integrity of the pipe. You might have to consider mounting this (or any larger) monsters just for recoil's sake--good on ya! Thanks again for helping ...