regarding recoil, I use http://www.shooterscalculator.com/recoil-calculator.php Muzzle energy is related to recoil energy BUT things like propellant mass and momentum are significant. I plugged in the numbers for the 7000 grain projectile at 339fps in a 10 lb launcher and the recoil was considerable...

Here is something I've been working on for a long time. Access to smooth tubing is easy, but access to strong smooth-inside tubing is not always. My options are to order seamless steel (I shall when the time comes) or work with commonly available materials. kevlar tube close.JPG In another life I ha...

This makes me look like a pnoob but I actually learned a lot. I find sprinkler valves in the ground and take them home. This is a 1" Hunter chamber sealing valve, piloted by a modified blowgun I had almost given up on. Unmodified it produced a bit of honking. I can't see how it would have worked wit...

That's lovely!

It's always more work than we think! You get it to shoot... now to get it to cycle... then the feeding... I have many unfinished projects because I have many projects! It will be awesome to see this function. It would be even more awesome to see the valve assembly for sale ;) Now let us stop distrac...

I'm very much looking forward to this!

Select fire, full, or semi? I've been working on disconnector designs and come up with a few things but open bolt full auto is the ultimate in simplicity.

Potential for quiet launching of very heavy projectiles

Another Canadian here... just took me this long to get my password

This is important stuff!

extreme pilot!

not enough barrels for that test

Wyz2285 that was a fascinating read. Thank you for posting that. I don't have the physics background to comment intelligently, but I have been working on ball bearing and marble accuracy and preliminary tests suggest blowby improves accuracy with hard spherical projectiles in hard barrels. I was sur...

We don't use a lot of pressure rated pvc in my area. I assume that's why it's rare and expensive.

I tried casting an endplug 2.5" diameter in thin walled plastic pipe... heat from curing slumped the thin pipe... may try to cast again in layers so it doesn't get so hot.

In 1/8 thick 1.125" od polycarbonate the casting went well, a little heat and it slid right out

300ish psi The whole concept is a little odd... I feel rubber either holds air or it doesn't. Soft rubber inner tubes hold air... balloons do pretty well for a day or two. Worst case scenario I can put an o-ringed job into the syringe if the syringe head starts leaking. I only have one single stroke...