SpudFiles

I'm thinking a hammer housed in a tube with a weak spring. When fully extended, the spring should not have enough force to open the valve, but with some momentum, it can open the valve for just a moment.

That's how Brian did it I think. Use it.

I'm coming back to this project after some frustration with other things, and now I have a 700psi regulator. I'm going to use a 1/2"x12" steel chamber at 700psi, and I hope to get 6 good shots with either .177pellets @ ~1000fps or .22pellets @ ~700. Does this sound possible?

It doesn't sound right. Most commercial pcp pellet guns require a couple thousand psi per fill to reach those velocities. I realize that it is also so that it can achieve more shots.

I'm sure someone will come at you with some math and prove me wrong.

those numbers are probably pretty optimistic, I would be ok with 850/600, but I don't really know how I'll be able to make any calculations

If I had a 1/4" QEV piloted by this "hammer valve", would there be a huge increase in performance with out sacrificing shots per fill?

Gaderelguitarist wrote:It doesn't sound right. Most commercial pcp pellet guns require a couple thousand psi per fill to reach those velocities.

True, however their hammer valves tend to be quite low flow. Using a burst disk valve in this project I got 720 fps for a 0.22" pellet with "only" 400 psi.

With a long enough barrel and a carefully constructed valve that keeps dead volume to a minimum I would say your ambitions are realistic in terms of performance, you will definitely get something in the 500-600 fps bracket for 0.22" pellets, and more than 6 shots per fill.

Have a look at some data for the Crosman 2240, a CO₂ 12 gram is very roughly analogous to your chamber size and pressure.

I could fill the chamber with unregged CO2 for more shots and more power, but I can experiment with that once I get a new tank of CO2. All I can do is build, but not test at high pressures, so I'm wondering if the addition of a 1/4" QEV would hugely increase velocity?

EDIT:
also, what do you think of 1417A1 on McMaster-Carr as a hammer. I got the idea from a how to for a zip gun on youtube

The QEV would certainly allow better performance, but you're also losing some air through the pilot so it might still even out in terms of shot count.



Looks like it could work, assuming the spring is strong enough, and it's fitted in such a way that it doesn't continue to press on the valve when in the "fired" position.

The spring in those is certainly strong enough.
We sell them at work.

But unfortunately they do push all the way, so the valve will remain open.

I did not use a tube and spring kind of hammer.
I used a hammer kind of hammer....

Brian the brain wrote:I used a hammer kind of hammer....

You mean there's a small person inside your launchers

Yes.
That is exactly what I mean.

You should see my new leprechaun powered blowback rifle.
It is way more compact than my Pigmee gun turret.

That diagram totally reminds me of Hapland... lol... thats pretty funny.

I made a flintlock style hammer mech with some sheet PVC, but after a few shots it cracked. Do you think polymorph would handle the force better?

Gun Freak wrote:That diagram totally reminds me of Hapland... lol... thats pretty funny.

My generation had Lemmings on their Amiga 500 (512 kB of memory man )

Lockednloaded wrote:I made a flintlock style hammer mech with some sheet PVC, but after a few shots it cracked. Do you think polymorph would handle the force better?

I doubt it, no sheet aluminium?

I don't have the tools to make the curved cuts that I need, and I would have to order sheet aluminum as well

I think you could manage with a dremel