SpudFiles

It's been a while! Hi all!

I want to share my finished project with you all so I can get some feedback and to offer my creative contribution.

At the heart of the gun is a scaled down Quick Dump Valve (QDV) which is Technician1002's design. Thank you! I chose this route because I wanted something simple and mechanically actuated.

Here are the basic specs:

Barrel: 1/2" Type L copper tubing and 32" long (smooth) UPDATE: Changed to rifled barrel (see below)
Chamber: 1/2" threaded brass fitings
Valve: QDV
Working Pressure: 800-850 psi
Operation: Single shot

This gun was primarily made with just hand tools. I did use a electric hand drill too, soldering iron, and blow torch. I machined the piston by chucking it into the hand drill and clamping the drill down to a table on its side and taking a file to it.

I think the only innovative design aspect of the gun is the stock I made for it. It's a clamshell! It's made out of flattened and laminated ABS DWV pipe. I cut the shapes out using a soldering iron with knife attachment. I joined the layers using ABS cement. And I devoted long hours to sawing, carving, and sanding it for ergonomics. There is an upper and lower receiver which are easily joined/separated with a single bolt and wingnut. I really enjoyed working with ABS because you can weld it, melt it, glue it, cut it, drill it, bend it, impress it, and even mold it too. You have to be careful about what you breathe so I invested in a respirator with a charcoal filter. This was handy for using the soldering iron on the plastic!

Right now I have a 3000 psi 47 cubic inch aluminum paintball tank and remote hose to hook up to the gun via fill nipple. The regulator brings the pressure down to ~850psi. To load, I unscrew the copper barrel from the brass nipple, slide forward, insert ammo, slide back, and screw it back in. There is no safety feature built in yet. And pull the trigger. The gauge in the stock goes from 0-1000psi for an indication of the pressure output from the source.

I've only been able to dry fire it in my storage room with a bag of clothes as a silencer and it still makes quite a loud *THUD*. When I get a chance to fire it outside with ammo I'll try to take a video.

And the rest is just pictures with captions. If you have any questions, please ask and I'll do my best to answer them!

But here's the trigger mechanism first >>> [youtube][/youtube]

Nicely done. That stock is beautiful.

I'm curious though... What was the respirator for?

The respirator is to protect him from toxic fumes...

I feel a muffler would look very good in this thing...Every part of this launcher has been thought out to perfection.
Very well designed and executed!

Very good job! I can tell you did indeed spend a lot of time on that stock, and component placement/etc. was very thought out.

You didn't mention performance though.

Thank you for the positive feedback!

Brian the Brain: When you say muffler do you mean a silencer? I've thought about making an integral one that permanently fixed to the upper receiver so I wouldn't need a license for it. We'll see how loud it is outside though.

Which leads me too...

mark.f: I have no idea what the accuracy or speed is, but if all goes well, I might have a chance this Tuesday. I plan on having my friends take a video.

06/14/2015

Update! Today I went into the woods to shoot at a 3/4" thick particle board target measuring 10" X 16". I used my scope and attempted to zero it out at 75ft. After getting it somewhat narrowed down I could hit the board every time. But I noticed the balls were curving too. So I need to design better ammo. To get around using wadding I dipped my balls in some wax to make up the slop in the barrel. This probably is what caused the balls to curve. As for amount of shots, I started out with 3000psi in the tank and after 20 shots I was only down to 2000psi (remember the gun runs off 800psi) See pictures! >>>

When you say muffler do you mean a silencer? I've thought about making an integral one that permanently fixed to the upper receiver so I wouldn't need a license for it. We'll see how loud it is outside though.

Can't see where you're from so ...I didn't think about local legality...but yes..I meant a sound supressor.

I love the stock!

I like the trigger linkage too.

STUNNING - really love the look of the whole gun and particularly innovative stock.

I realize there are a few QDV diagrams around and I have read about them, but most seem to be larger calibre. If you have time could you please explain in simple teerms how your QDV is constructed, functions as would love to be able to replicate it if you don't mind, please bear in mind I am new to building valves, so keep it simple for me

Ps what is the little gray/blue part with the hole through it?

Ianbuckwell wrote:Ps what is the little gray/blue part with the hole through it?

auxiliary wrote:I used a bic pen to restrict airflow to the gauge to prevent damage caused by sudden pressure loss upon firing. The hole is so small that the gauge goes down 100psi per second after firing.

Really nice gun, I'm assuming you screw on to the Schrader valve instead of using a check valve? Also, do you screw the barrel assembly onto the breech each shot or does it slide in? Thanks, beautiful work !

Ok, thanks sorry I missed the description under photo. I really love the design/style of the gun, especially the stock, really finishes it off giving it a professional manufactured look, but at the same time better as it is unique, I hope you are proud of it, I know if I could make something that smart I would have a big grin everytime I looked at it, this is one of my favorite guns on spudfiles and any other homemade guns I have seen, Well done its superb!

Wow I appreciate that a lot!

So I made some changes to the gun... I received in the mail my 10.5" long 1 in 12" twist rifled long Colt barrel. Got it here: http://www.ebay.com/itm/45-Caliber-Rifl ... 1628797451 I made a bolt action mechanism using 1" PVC pipe. I created a new upper receiver to mount the scope.

I made a video that you may be interested in watching. It should answer some of your questions. Plus I do target practice!

[youtube][/youtube]

I little description of my ammo... For the cement bullets I used "Rocktite", this stuff with a creepy picture of a man. It's a mixture of gypsum and Portland cement. I cast them using a wooden mold I made. The wax I used for dipping is beeswax. As for the darts, I used that paper packing tape that's like masking tape, but stronger. I think that shooting these off in the woods won't have as much an impact on my environment as lead would.

Since moving to a 10.5" barrel rather than the longer copper one have you seen a noticeable decrease in power? Or is your valve so fast it makes little difference?

I think my shots in the woods yesterday were less powerful because the ammo I was using wasn't precise like the .535 cal round balls I was using before. But even if I did have nice lead bullets for it (which will happen soon so stay tuned), I would expect less projectile energy because there is less area for the pressure to push on the projectile and less distance for it to push it. Work is force X distance. I will be trading energy for accuracy basically.

Beautiful gun I've gotta say, good job, I really love the stock, reminds me of the assault rifle from Halo. Just out of curiosity, is there a difference between a quick dump valve (QDV) and a quick exhaust valve (QEV)? Just wondering because I haven't heard of a QDV before.