has anyone ever tryed to make a burst shotgun?

[Zoltar9879]

Hi everyone, I've been a lurker for a while and decided that I finally have an idea worth posting. I have been working on a shotgun that will fire a burst of airsoft bb's, preferably in the range of anywhere from 30-100 bbs. I started with this idea http://www.boltsniper.com/BS-3/BS3.htm but the problem was that I couldn't get the shells to eject properly, so now I've been redesigning the whole thing to be shell-less, and also semi-automatic (one trigger pull= one burst/shot fired). so what I have right now is something like this. (sorry about the drawings, I don't have access to any pics right now. no camera)

NOTE: There is a mechanism in the barrel that holds the bb's in until enough pressure lets then be pushed past it. this keeps the bb's from rolling out of the front of the barrel if/when it is pointed down.
Also, this is going to be used for AIRSOFT bb's ONLY, and I will test this on myself before I use it in a game, and will double-check with the reffs before any games, to make sure that they think it is safe to use on the field that I play at.

= --Bolt
-- --outer piece of pvc and barrel
+ -- plugs on end of pipe and bolt stop
O -- O-ring to seal barrel and bolt
* -- empty space

So this is how the gun would be when at rest and with no air

---------------------------------------------------bb's enter here---
----------------------------------------------------*************---
----------------------------------------------------**************-----------
+++ = ******spring**********(spring stop) **************+++++
+****======================== *****************O-------
+hole++++++++++++hole++++++++++********************-->
-->air in =+blocked+= mesh******************barrel
+hole++++++++++++hole++++++++++********************-->
+****======================== *****************O-------
+++ = ******spring**********(spring stop) **************+++++
-------------------------------------------------------------------------------

And this would be the gun with the trigger pulled and air running through it (as long as the trigger is held down, there is going to be air flowing through the barrel). The bolt is pushed forward and seals off the loading tube/mag/whatever gets put there. As the bolt gets pushed all the way forward air is allowed through the forward holes and down the barrel, pushing the bb's down and out of the gun in a single blast.

---------------------------------------------------bb's enter here---
----------------------------------------------------************---
----------------------------------------------------**************----------
+++*******************=spring(spring stop)**************+++++
+********************* ========================O-------
+hole++++++++++++hole++++++++++********************-->
-->air in =+blocked+= ************mesh******************barrel
+hole++++++++++++hole++++++++++********************-->
+********************* ========================O-------
+++*******************=spring(spring stop)**************+++++
-------------------------------------------------------------------------------

When the trigger is let up, the airflow stops and the bolt is pushed back to it's staring position, allowing bb's to drop into the chamber.

I plan on running this on regulated co2 with a paintball tank and a palmer stabilizer. My main questions for you guys is, in your opinion, would this work? and how can I improve it? maybe make it selectable (full or semi)? I have tried brainstorming over this and have had no ideas on how to get this to work. I don't have any advanced tools, just some basic hand tools and woodworking equipment. Sorry if this is to long, I tried to get it as short as I could without losing any of the information.
Any help would be greatly appreciated, thanks in advance,
Zoltar9879

(I'll try to get pics up if I ever get a camera)

[chinnerz]

well.... i would srsly recommend a program called paint.net. its good for drawing diagrams and doing other graphics (make sure you get a bunch of plug-ins)

as i do not understand what your gun is going to do, i can only make suggestions about how to achieve your goals.

why not make shells out of paper which "unravel" while in the air. i make them out of paper.

what if you had a primary tank and a secondary tank. that will make it more efficient. a member called iknowmy3tables came up with this which may be of interest. they will work with piston valves

[Cannoneer]

While I cannot understand you're diagram Ive got an idea that could be suitable. Recently I built a vortex cap BBMG it has a capacity of only 110 rounds. Due to the fact that it needed to be portable I built it with a small hose as a momentary chamber this let's it get bursts of 10-30RDS per trigger pull. It uses a 20" carbon arrow with a hopup for a barrel however it doesent shoot in a stream instead it works very much like a shotgun. This design has several key advantages: it's much easier to load,the momentary chamber is small so it fills quickly making effectively semi automatic and it's clean with no moving parts. Obviously Ive tried this and it works really well. Hope this helps.

BTW I am using cheap propane not co2.

[Zoltar9879]

sorry about the bad drawings. I am running a version of ubuntu on my computer, would paint.net work with this?

Ok, I did some more searching and came up with an idea that jackssmirkingrevenge made http://www.spudfiles.com/forums/6mm-sem ... 10075.html basically what I've been trying to do is scale up the mechanism that he has made so that the barrel is 1/2-1inch pvc, with some changes to the setup so it can handle several bb's at once.

chinnerz, I've thought about making shells, but at the field that I go to I would have to go back and pick them up after each game (and I am to lazy to do that). Also I would like the launcher to be able to handle bb's by themselves because I would like to make mags/clips for this if it works, and I've failed at getting shells to load.
Cannoneer, I searched but couldn't find your post, could you send me a link?

Thanks for the feedback guys. I'll try and get better pics/drawings up as soon as I can.

[Technician1002]

sorry about the bad drawings. I am running a version of Ubuntu on my computer

Install The Gimp. I use it for edits and drawings as well as photographs. Sample edited photo is below.

Edit, I found another photo I did long time ago. I composited some photos together with a drawing to show the internals of my Mouse Musket.

[Zoltar9879]

thanks, I should have pics up in a couple of days

[SP00K]

Burst disk shotgun? Possibly like this: http://www.spudfiles.com/forums/paintba ... 16727.html

[Zoltar9879]

spook, that looks good, but I was hoping to have a shell-less shotgun (for ease of use) less parts=easier to use.
Also if I use shells then I have to work in a feeding/ ejecting mechanism.
I will definitely be trying that shell idea though. I have an idea for some sort of grenade launcher out of it. (maybe take the pens and replace them with longer barrels?)

[Cannoneer]

Sorry I haven't posted it yet(no camera at the moment) it's not impressive visually it's just a typical vortex cap that has a body/stock and is portable. I will however post it and a bunch of other things soon.

[Zoltar9879]

No problem, with finals just about here I'm going to be unable to work on any projects for a couple of weeks.

[Zoltar9879]

I tried to upload a pic with gimp, and got this error mesage,
The Extension xcf is not allowed
How should I fix this? I tried to save it as another file extension, but it still didn't work.

[Technician1002]

Do a save as. Save as a jpg or png. Be sure the photo is not too large. For posting here, high megapixel photos are changed in size by using the Scale image tool under Image. I found 640 pixels wide works well.

[Zoltar9879]

ok, here is a rough diagram that I drew up.

Blue is the bolt
darker purple is where ther is holes in the pvc for air to flow through
pink is filler around the barrel
black is the outside shell of pvc and the part that the bolt runs on
light blue is the air inlet (this will have a ball valve on it soon)


When the ball valve is opened, air slides the bolt forward and cuts off the loading tube at the top. As the bolt reaches the end of its movement, it allows air to flow through the front holes and into the barrel. this pushes out the bbs. When the air flow is stopped, the spring around the bolt pushed it back to it's starting position, allowing bb's to drop into the chamber.
I already have something in the barrel to keep bbs from falling out the front if I tilt it down. I'm planning on starting work on it this weekend, so I should have pics up as soon as I can get a camera. My main question is, does this look like it would work? and has it already been done in a way that is easier to build? Thanks for the help, I'll probably have more questions as I run into problems I can't handle or can't find a way around.

Sorry about taking so long to put up usable pics and constructive criticism is welcomed.

[kozak6]

http://www.gizmology.net/pbm.htm

[Zoltar9879]

Thanks for the link