Blow-dart combustion gun **updated slight mod.

[Radiation]

**please see my comments on the second page for updated pics and info.
Thanks!

Hello everyone,

This is my first post to this site! I've been building spud-guns since I was a kid. I recently got back into the hobby and have made a few new designs that I think are pretty original and successful beyond my wildest imagination. Any way I wanted my first post to be something special.

I was working on bigger, better, more powerful spud-guns until I hit a bit of a wall, both creative and financially speaking. So I sort of went from going BIG to experimenting with smaller designs. Low and behold my creativity returned when I wasn't obstructed by prices! Here is my best "miniature" combustion gun.



This represents the apex of my small guns design research and development. I call this the MCB-MK3 (modular combustionblow-dart third iteration there are pics of MCB-1 and MCB-2 further down)

Description:

3" sch-40 PVC chamber 15" length
180 degree elbow to allow longer barrel yet smaller overall size 1" pvc
1" to 1/2" reducer for 60 caliber blow darts
Weber BBQ ignitor
Chamber fan
Internal Electronics for chamber fan (on/off switch, wiring)
36" blow-dart gun modified to fit from 1/2 pvc to .40 caliber.
8 dart revolver for quicker reload
accommodates 1", 1/2" (.60 caliber), and .40 caliber ammunition of various types.
Butane based.

BTW this a great and easy way to mod a butane canister, just use any nozzle from an old aerosol can and a little electrical tape.


Because I didn't know a site like this existed prior to about 2 weeks ago, the MCB-MK3 is a gun designed from many ideas and experiments that I have come up with independent of any outside source and am pretty sure there isn't anything quite like it around (though judging from the vastness of this site, it's likely that there is something similar that I haven't come across. ). Combine that with some good ol' fashion spud-gun know how from yours truly.

It is a completely modular design in that you can shoot from barrels that are .40 caliber, .60 caliber (the actual size of "1/2 inch" PVC which is actually a blessing, more on that later) and 1". you can also remove the elbow for a more traditional spud-gun appearance, but I prefer it with the elbow, it's easier to aim.

The most enjoyable part of the design is the ammunition! Here are most of the types I have either invented or purchased online.



From left to right: BBQ bamboo skewers, about 10" long, (I purchased a bag with 50+ skewers for about $1.50. Wrap that with either plumbers self adhering rubber or foam tape and you have an extraordinarily effective and cheap dart. I shot one at an old chair and the damn thing went all the way through to the end-cap.) 5" nail (one of the best unbelievably powerful.). Stun dart - just self adhering rubber wrapped around itself. Marble, .40 caliber nail dart for small game, .40 caliber needle dart, .60 caliber nail dart, and .60 caliber small game dart.

All these darts are designed for small game, but with this gun I doubt that limit still applies.

Here is the inside of the gun:



Unlike anything I've seen so far (or designed myself) this guns electronics, including the battery are all housed inside the chamber leaving a clean and deceptively simple look to it. The Fan is a 2" Radioshack I came up with a way to mount it in the barrel using 2" PVC without drilling holes, yet still maintaining security so the fan doesn't get blown away by the force of the combustion. The battery is mounted to the side wall again preventing it getting blown away from the combustion, yet making it easy to remove when dead. Last but not least the switch is the only electronic piece you see outside the gun.

Here's the ignitor:



Now onto the barrel:


the revolver allows 8 .40 darts or nails to be loaded. Being that this is a spray-n-pray design this drastically reduces the amount of time it takes to reload, all you have to do is spray! I have to be careful as it takes less than a few seconds to load and the gun gets rather warm.

For the larger modified nail darts and .60 caliber nail/small game darts I use 1/2" PVC. The inside of this PVC actually measures .60 which is perfect for Cold Steel brand blow darts. It's very tight in the barrel, so tight that I can't blow one out of it, but when I shoot it... well here are some pictures of that!



The shot is so powerful that the homemade nail darts have a tendency to to bend in half upon impact. They also have the tendency to...



...go all the way through. This is a 2X9" board by the way! Using this gun to shoot at softer targets the nail darts end comes off and the dart penetrates very deep. For instance I shot a 5" thick wax candle and the dart went all the way through and stuck into the wall! (sorry no pics of that.)


As for the .40 caliber nail darts, here's how they do, I tacked one to the board to give you some perspective as to how far in those little things go!



Here's one of how far I can shoot one in with just my breath and the 36" blowgun and I'm a great shape to!


Last, but not least here is a "family picture":



From the bottom, MCB-MK1, MCB-MK2 (that's right it's a double barrel with valves for single barrel conversion! Also has an internal fan. Fully modular), and the big daddy MCB-MK3.



Thanks for looking I have throughly enjoyed this site and wanted to add something of my own. Feel free to add anything, questions, comments etc. BTW sorry for no video link, I don't have a V-camera.

[starman]

Goodness, this is a cool little system you have here...and your ammo and damage looks absolutely brutal...in a good way of course. Can you give us a little more detail on your dart revolver? Is it a unique design of yours?

You don't see very many fans in spray n prays. Have you thought about doing a metered propane injection? It would be a cinch to add it to your chambers here and would bring performance and reliability up a big step.

Welcome to Spudfiles! A very nice entry for your very first post! I like your ingenuity here.

[Radiation]

Thanks Starman, the Revolver is not my own design. As a matter of fact you can buy most of the stuff you saw on my post from here: http://www.jungleblowgun.com/

The revolver is cheap, I think it's like $10.

As far as the propane injection, this is exactly why I love this site! I have never tried to make one, but would love to learn how. Do you have a link?

[jon_89]

Looks pretty nice. I like things that are simple. I was looking at those blowgun revolvers for a cannon. Here ya go http://burntlatke.com/lp.html

[starman]

As far as the propane injection, this is exactly why I love this site! I have never tried to make one, but would love to learn how. Do you have a link?

You can go to Latke's siteto learn all about propane metering ad nauseum. Most people have built on-board meters like latke's. I have just finished thesewhich uses an external syringe or fuel cell as Deadeye likes to call them, to meter and inject propane.

Jimmy101 has experimented with a method using a real needle and syringe and lighter parts, here at his website

Once you move away from the spray n pray MO you don't usually look back....unless you just want to of course...

[Radiation]

Thanks for the info. I might have to look into that a bit. I'm also thinking about applying this design to a pneumatic/CO2 based gun, but having never built a pneumatic I think I'll hold off until I have a much better understanding on them.

Side note. As I said in the post blow dart guns are intended for "small game" I have hunted squirrel and rabbit with the blowdart gun using only lung power and it is highly effective. With the MCB-MK3 I have no doubt that I could take down much bigger prey than that with no problem, this thing is down right lethal and I'm not talking about for little woodland creatures.

[starman]

Side note. As I said in the post blow dart guns are intended for "small game" I have hunted squirrel and rabbit with the blowdart gun using only lung power and it is highly effective. With the MCB-MK3 I have no doubt that I could take down much bigger prey than that with no problem, this thing is down right lethal and I'm not talking about for little woodland creatures.

I personally think it's cool...but...take a quick read of the Spudfiles rules. It specifically prohibits discussion of shooting, hunting, killing anything living...I'm paraphrasing here, but hopefully you get the picture.

[Radiation]

no harm meant. I will refrain from such talk in the future. Thanks for the heads up.

[starman]

Nah it's cool, you didn't know. Do read though the rules though. It will give you a leg-up in posting and communicating with the other members.

One thing, do your reasonable best with your grammer, spelling, punctuation, sentence structure etc. You don't have to be perfect, just make an effort...yah it's in the rules too...

Respect others and think through your responses when you post. You'll go far...

[psycix]

That revolver is literally awesome!
Thanks for posting the link.
Do you think it will stand up long to the combustion heat and pressures?

[dudeman508]

What size PVC did you use to atach to the revolver

[mister pointy]

Awesome first post! I have never seen all of the electronics mounted inside the chamber like you have done. Your blowgun revolver and damage pics are impressive as well.

I agree with starman, adding metered propane to your gun would really make it shine. Can't wait to see what else you come up with

[Radiation]

Thanks guys! I really appreciate all the feedback.

psycix to answer your question, I have yet to see any detrimental effects to the revolver, however only time will tell, it is plastic, but then again so is the PVC. So far so good.

dudeman508 the PVC I used is just standard 1/2" PVC. Because there is a size difference I simply used electrical tape to wrap around the revolvers mounting attachment. It was originally a quick fix, but it worked so well I saw no reason to change it.

Mister pointy, thanks for your compliments! As far as mounting the electronics in the chamber I originally had my reservations, but thought "eh what's the worst that could happen? A leaking battery?" So far I've not had any problems with the setup and because Butane burns so clean there is no residue build up. Though it can be a pain to get the mixture right, i'll have to look into metered propane.

[skyjive]

In your damage pics I couldn't help noticing that the darts are sticking out of the wood at all sorts of angles. In my experience with darts, this generally means that they were fired from close range and were ballistically unstable, i.e. were starting to tumble in flight but didnt have time to tumble too much due to the short range. Alternatively, they could have been fired at the target from different angles or bent on impact. Have you tried shooting these projectiles at long ranges? If so, do you know if they go straight? Those darts look very deadly if they could be fired straight and accurate at long ranges.

[Deadeye]

Very cool gun - I love how your last photo really depicts your thought processes and variations on the multiple builds.

On a whim I bought one of those 4' blow guns at a gun show and was amazed at its accuracy, of course I was very limited by my own "internal combustion" for velocity which you have apparently rectified based on your damage shots... sorry for the run-on sentence.
Really like the uniqueness of this gun, and glad you posted it.

I have a couple of questions.

Your fan looks to be between the combustion chamber and barrel and as such, do you think this is limiting performance by resisting or stifling the force?

It looks like you have your fan aimed into the chamber, which would pull in air down the barrel and then into the chamber, which might take longer to "refresh" the chamber. It might be with the clean out you don't need the fan as much for evacuating gases, & use it more for mixing?

I like the internal electronics, don't think I've seen it before, but I have pondered it. I would like to see the condition after 100 or so shots which is what kept me from trying it. I especially like how you used pieces of pvc for the mounting (or at east that is what it appears). That being said you will have a little hiccup when you learn more about metering and need to calculate the combustion chamber - but a little guess work shouldn't hurt.

Having to do with the fan I have a suggestion for MCB-MK4 or a mod for this one.

How bout kind of a dual chamber, with a ball valve instead of cap.
At the end of the chamber where you have a clean out cap, instead put a
3" male threaded coupler, then a reducer bushing to a 2" ball valve and then reverse it back to 3" and put your fan, batt, and switch on the other side of the ball valve blowing toward the chamber into the barrel.

would make reloads even faster but a few more bucks - what's new?

My second variation would be a the same only put the ball valve all the way at the end and the fan and electronics between your existing chamber and the ball valve.

Ex 1 puts it all out of the blast zone -- don't see this much
Ex 2 puts it all at the end of the blast zone

Of course both require a relocate on your igniter which I doubt would be a problem for you since you have a very simple igniter. Don't forget to put it in an area of double layer if you can.

I drew up example diagrams for both for better explanation -
After I saved it I realized I goofed. In example 1 you would want to move the fan all the way in (left) and put the electronics outside of that for easier access to the batt.

Just a thought - (inspired by your current design) -
If anyone else can see any kinks - please chime in - I will happily stand corrected.

Again nice job Radiation.
See you'll