The Hammer Shotgun

[jackssmirkingrevenge]

I don't claim to have any original ideas, flip through
Google^TM patent search and you'll know what I mean. I think the skill lies in first of all recognising existing concepts that can be applied to spudguns, and secondly having the material know-how to be able to flesh out your designs.

[Davidvaini]

I've already been a step ahead of JSR.. actually a few steps... I'm talking about baking a cake of course....

[Ragnarok]

To what extend this idea actually does this remains to be quantified.

One problem that needs to be addressed is the large pilot volume that is required.

Now, here that won't limit opening time badly, but the further a piston moves back, the more energy it takes out of the chamber, which could be a significant reduction in a small chamber volume like this one.

[Novacastrian]

Here is the only pic that wanted to work of the new piston.

[jackssmirkingrevenge]

The further a piston moves back, the more energy it takes out of the chamber, which could be a significant reduction in a small chamber volume like this one.

That is a factor but it can easily be compensated for in this case by adding an inch or so to the chamber volume, no big deal.

Nova, that's exactly how I had pictured it originally can't wait to see it in action

[Novacastrian]

Here i go with the vids, the first shows activation. However i am not sure that the frames portray it well. The pistons travel backwards and forwards very fast, and reseats itself. The other vids are self explanatory.
<a href=">

<a href=" can</a>
<a href="http://www.youtube.com/user/TyaxComp">Water Bottle</a>
<a href=" thick acrylic</a>

[jackssmirkingrevenge]

yay! great stuff

So you're saying that the piston travels all the way to the end of the chamber, hits the endcap and bounces back?

[Novacastrian]

So you're saying that the piston travels all the way to the end of the chamber, hits the endcap and bounces back?

That's it, the big or back portion bounces on acetal to acetal, the middle portion bounces metal on polyurethane, about as hard as a rubber band.

[jackssmirkingrevenge]

Interesting, perhaps a larger chamber would leave the pressure on firing higher for longer, dampening the bounce. What pressure were you firing at?

[Novacastrian]

~100psi, i am confident that the projectile has left the barrel before the piston bounces back, plus as the pressure leaves the pilot and chamber at the same time, i am lead to think that if there where still pressure in the chamber the piston would not bounce back "at all". It is a fairly large pilot for the size of cannon. Nuff talk, i'll have to wait and do a comparative test after i get a chrony

[jackssmirkingrevenge]

Only 100psi?

*cough*shockpump*choke*itcanprobablytake200psi*splutter*smallerlauncherslovehigherpressure*bark*

Anyone got a throat lozenge?

[Novacastrian]

Only 100psi?

*cough*shockpump*choke*itcanprobablytake200psi*splutter*smallerlauncherslovehigherpressure*bark*

Anyone got a throat lozenge?

Fair suck of the sav! One knows that higher pressure yields more power I would like to get an efficient design built before i start pumping!!

[Gippeto]

That works slick!

I like it, I like it a lot.

[Novacastrian]

That works slick!

I like it, I like it a lot.

Thanks Gippeto