SpudFiles

This is my latest project, a self-contained pump pistol.

I'm very happy with the results this thing has yielded, but to my dismay, the 5/16" barrel does not fit airsoft BBs very well . I can still get some pretty impressive results though..

this gun consists of a 1' long .5" copper chamber with an 11" long 5/16" barrel. The piston is a trimmed down solid rubber stopper, and the gun is piloted through a modded blow gun despite the fact the gun can be piloted with ease through the shrader.

It is extremely easy to pump up even with just a shock pump.

Performance:
@ 75 psi I can shoot through both sides of a soda can (ormal airsoft velocity/ 10 pumps)

@ 150 psi It goes through the bottom of the can with ease, (20 pumps, ~500 fps)

@ 250 psi I can shoot through both the top and bottom of a can in one shot (30 pumps)

@ 400 psi I can shoot through both sides of an empty soup can and deafen anybody within 25 feet of the gun (An ungodly amount of pumps)

Now for the part that most of you will actually look at...

The whole thing


Close-up on the grip (kinda sloppy)


View from the top


I plan on adding a rail mount and a red-dot site to the top, but tell me any suggestions you have..

Thanks for making it this far, please comment and critique all you want

hey it looks good any chance of a vid of it at 400? i have been thinking bout making something similar and would like to know what the performance is like, thanks.

Looks good, hows the accuracy with the brake line barrel, and is that a Planet bike Shock Mate Pump

@ ilovefire- I recommend everyone builds one of these, I'm making a similar one for .177 pellets right now. Its a great, reliable design. Sorry, but there will probably be no video at 400 because I lack a proper video camera and I hate taking it to 400. If i take a video; the highest I'd go is probably 350.

@Clemsonguy- Its impressive, I can hit a soda can at 30m with a wadded airsoft BB. With no wadding its accurate up to 10m as long as you don't aim down. On the shock pump, I believe it is; it was 20 bucks and is higher volume than any shock pump I've ever used

Cool I'm looking for one for my pen gun, where did you get it?

I got mine at REI specifically for this project. Its pretty high volume as far a shock pumps go, bu it has a 400psi gauge and a removable grip (so you can replace it with a better one) It was 20$

I also have a bontrager brand pump, Its gauge only reads 300, but it is lower volume and much easier to reach 400psi with. It was 25$

Nicely done, shame you're being let down by the loose barrel. Have a look at my suggestions here.

You might also want to consider a more ergonomic handle for the pump in order to make it easier to get to 400 psi, as well as connecting the pump directly to the pilot chamber in order to cut down on both pilot volume and pumping effort.

Its not so much room that it can fit another piece of copper in there, but it is too loose to hold a bb tight without wadding. The other option was 1/4" copper tubing which is like 7mm ID so this is much tighter than that.

The pump handle could easily be replaced, the current handle can be unscrewed. anyone got any diagrams for a benjamin style pump likee on air guns, the design is troubling me ATM.

disconnecting the pump pilots the gun about 80 percent of the time, so I'll probably leave it there. The blowgun pilots it very well, actually its over kill because i can pilot through the shrader.

Lockednloaded wrote:The pump handle could easily be replaced, the current handle can be unscrewed. anyone got any diagrams for a benjamin style pump likee on air guns, the design is troubling me ATM.

Very easy, you can even operate it virtually Having it on a lever will certainly reduce pumping effort.

any ideas on a similar system without modification to the pump?

and BTW, you're about to go 12345 on your post count

Lockednloaded wrote:any ideas on a similar system without modification to the pump?

Drill a hole through the handle and attach it to a lever, I doubt it would be pretty but it's certainly viable.

and BTW, you're about to go 12345 on your post count

As the person responsible for 4.38% of all posts on a forum with 8445 registered users, I'm not sure if that's a good thing :s

All we need now is a homemade 12 gram Co2 powered pistol at full co2 pressure preferably small in size,ive not found a way to do it yet!?.

Maybe one day someone will?, I'm tired of mates asking me to make such a pistol for them but I just dont see how?

With a co2 to 1/4" NPT adaptor it might just work with this gun. The only limiting factor would be the connection of the male adaptor to the chamber. If I were you, I'd use 3/4" type K copper pipe and the same configuration with a hose leading to a CO2 capsule adaptor under the barrel. It wouldn't be multishot, but at those pressure, one is enough

@django
I think that a simple QEV + DCV combo is the answer... but you need a way to lower the pressure to 500 psi or so

Its literally always the answer isn't it...