24 replies to this topic

[Dyxlesic]

Introduction:
Alright, so this Is something I have been working for a few weeks, but haven't mentioned. I was gonna keep it secret untill i finished, but hey, this could really help someone in the homemade contest. This is a simple working concept that I am in love with. I have looked and found nothing like it, but it may have done before. It will be a while before I finish it, but I thought I might share it with someone so they may have one of those OMG THAT'S IT! moments.

Diclaimer:
Wile this is a concept, I have done some work with it, and will upload more pictures shortly. Some of the the stuff I put in the diagrams are not homemade. I put them there because it makes it easier to understand. Yes, i realize there are some things, but more detailed diagrams will be posted as soon as I can. Yes, I realize this is a concept right now, but I will post more really soon, as I am having technical difficulties, so please don't ban me.

So let's begin. What is the hardest part of a homemade, especially clip fed ones. The damn feeding system. Anyone can make a semi auto valve system, but making a breech that will go forward, fire, then back up is just a pain in the ass. And rate of fire is limited also by the fact that the dart can only enter the breech for a fraction of the full cycle. So I've been looking into alternate breech methods, and I finally got one

A rolling breech. Imagine an angle breech, but instead of a back and forth motion, it spins. Two telescoping pieces of brass each with a breech cut in it. The inner one is Spun by a motor. When the brass lines up, the dart slides in, when they are opposite, it seals. Combine that with an electrically operated switch at the bottom that triggers a semi auto valve, and you have a auto clip fed rifle. More info comming really soon
Here are some of my pretty pictures/diagrams


Hope you like
Here is a simple mockup of the breech. All my stores are out of brass, so I made it using spare parts.
Closed

Half open

Closed

Edited by Dyxlesic, 24 May 2011 - 07:36 PM.

[Daniel Beaver]

During one of the midwest mod parties we kicked around this exact idea. Here's the issue: darts won't feed into the brass unless it is at least 180 degrees open. When you rotate it around, you need some overlap, otherwise it won't seal. And because of that overlap, the breach opening can never be a true half-pipe: it will always have to be somewhat smaller than the dart itself.

[Dyxlesic]

During one of the midwest mod parties we kicked around this exact idea. Here's the issue: darts won't feed into the brass unless it is at least 180 degrees open. When you rotate it around, you need some overlap, otherwise it won't seal. And because of that overlap, the breach opening can never be a true half-pipe: it will always have to be somewhat smaller than the dart itself.

That is a great point. so you are saying in order for it to feed, the degree of the cut/opening has to be greater than 180, but for it to seal it has to be less than 180 correct? From my tests it seems it can load into it when it is slightly less than 180, however i am not 100% sure.

[238232]

Given that the inner tube is obviously thinner, perhaps cuts in the outer tube like this might work:


Red: Cuts
Blue: Just to show how it lines up.

so that the width of the cut is the same ID as that of the inner brass tube. Since the dart has to fit inside the inner tube, it should also fit through the cut.

Of course, given how thin brass tubing is, I imagine it would also be a royal pain to do. Maybe slightly thicker materials would be a better choice, or simply make the outer barrel from two tubes bonded together.

Edited by 238232, 24 May 2011 - 07:53 PM.

[Dyxlesic]

Given that the inner tube is obviously thinner, perhaps cuts in the outer tube like this might work:



so that the width of the cut is the same ID as that of the inner brass tube. Since the dart has to fit inside the inner tube, it should also fit through the cut.

Of course, given how thin brass tubing is, I imagine it would also be a royal pain to do. Maybe slightly thicker materials would be a better choice, or simply make the outer barrel from two tubes bonded together.

I couldn't think of any better way to word that. i was gonna post explanation of this idea here later, but i had no idea how to explain it. Thinner walls for this is better, but i did consider soldering two brass pipes together for each layer, to increase its structural strength. But thank you so much for putting this into better words, and better diagrams.
Cuts would have to be extremely precise. another problem encountered is the actual loading of the mag. like how you can only load the clip on an angle breach when it is in the forward position. but this has no forward position

[Split]

Wow. I had dismissed this idea several times, but had somehow overlooked that overlap. Very good work.
We were having a discussion on whether or not there would be enough surface area to make a good seal, so I did the geometry.
The arc length over which the two tubes are touching (and therefore make a seal) is L.

L = 2*2*pi*(r_i + w)*arccosd(r_i/(r_i + w))/360

Where
r_i is the inner radius of the inner tube (1/2" for 17/32 brass)
w is the wall thickness of the inner tube (1/64 for 17/32 brass)

For 17/32 brass, this arc length is only about 1/4" total, but if you use something like 1/2" ID 5/8" OD plastic tubing, the arc length is about .53" That's a surprisingly good number.
(It doesn't matter that much, but if you need the surface area for the whole seal, it's just the arc length times the length of the half pipe.)

A normal mill or even a drill press with cross slide vise and mill end bits could be used to make these precise parts pretty easily.
Nice work guys.

Edited by Split, 24 May 2011 - 09:02 PM.

[Dyxlesic]

Wow. I had dismissed this idea several times, but had somehow overlooked that overlap. Very good work.
We were having a discussion on whether or not there would be enough surface area to make a good seal, so I did the geometry.
The arc length over which the two tubes are touching (and therefore make a seal) is L.

L = 2*2*pi*(r_i + w)*arccosd(r_i/(r_i + w))/360

Where
r_i is the inner radius of the inner tube (1/2" for 17/32 brass)
w is the wall thickness of the inner tube (1/64 for 17/32 brass)

For 17/32 brass, this arc length is only about 1/4" total, but if you use something like 1/2" ID 5/8" OD plastic tubing, the arc length is about .53" That's a surprisingly good number.
(It doesn't matter that much, but if you need the surface area for the whole seal, it's just the arc length times the length of the half pipe.)

A normal mill or even a drill press with cross slide vise and mill end bits could be used to make these precise parts pretty easily.
Nice work guys.

Awesome. And to think I wasn't going to post this because i thought it would be considered a waste of space.
anyway, i will post a diagram of simple ways to manipulate this system. To summarize it up, there will be another switch like the one that triggers the release valve, only it will be 180 degrees off. This switch will be aligned in series with the trigger switch, so it will be full auto, but complete the cycle when the trigger is released so it always ends in the open position. pretty friggin awesome. i plan to have 4 models, each will add something better
m1: full auto
m2: semi auto (using "temporary" switch)
m3: semi auto/full auto selective
m4: burst (will probably need microchip programing)
m5: semi auto/burst/full auto
m6: semi auto (will fire from closed position to eliminate tiny lag between trigger pull and firing)
m7: semi auto/burst/full auto. (semi auto closed positon, burst and auto open position)

this system can be so small it could probably fit in a recon shell, with a backpack air tank. Im thinking i wanna make at least one of these suckers bullpup

[Blue]

I have a breach that works just like that. It has a very difficult time sealing, making it only usable in guns that could take a hopper anyways. It was done with a dremel and brass though, I'm sure that if a machine was making one it would function quite well. Nice diagrams too.

[KaneTheMediocre]

Thicker walled tubes will give you more angular overlap to work with using the aforementioned geometries. That said, the inside tube would feed best if either the wall was thin or if there was a slope in the opposite direction to "slice" between the darts. Another constraint is the ID of the snap-on thingy on standard nerf clips. Putting the clips over a tube that is substantially larger than it can stretch out said thingies, causing ammo to spill out of the clip when it's not on a blaster.

Edited by KaneTheMediocre, 24 May 2011 - 11:37 PM.

[Dyxlesic]

I have a breach that works just like that. It has a very difficult time sealing, making it only usable in guns that could take a hopper anyways. It was done with a dremel and brass though, I'm sure that if a machine was making one it would function quite well. Nice diagrams too.

Thanks. The seal seems to be the big problem. I originally wanted a door-like design that would reload itself from the force of the spring of the mag, but ditched it for this caus i couldent find any way to make it work. Anyone who has a breech like this, experience, or anything like that feel free to post it here. We wanna learn from others mistakes and successes. Don't feel bad about like hijacking as long it is on topic

On the drawings, I like to keep them simple and colorful, yet recognizable. It's pretty amazing in a ghetto way

[Dyxlesic]

Thicker walled tubes will give you more angular overlap to work with using the aforementioned geometries. That said, the inside tube would feed best if either the wall was thin or if there was a slope in the opposite direction to "slice" between the darts. Another constraint is the ID of the snap-on thingy on standard nerf clips. Putting the clips over a tube that is substantially larger than it can stretch out said thingies, causing ammo to spill out of the clip when it's not on a blaster.

I thought about that too. I was gonna mention it tonight, but was distracted by the cloud rotation, tennisball sized hail, tornado warnings and lightening (struck a pole in my yard) going on outside. The problem though isn't it stretching the clip caus the brass is so thin. I have accidentally tested this by leaving a clip on a 1/2" PVC pipe for like 4 months. The plastic on "said thingies" is pretty thick and sturdy. the problem is actouly getting it on, as the pipe is halfpiped

[Y-Brik]

Increasing the diameter of the 2 pieces of brass making the seal should increase the relative surface area avalible

If we glue the 17/32" barrel into a stub of 9/16" into which the dart can drop, and sheath that in 5/8", in theory we can have it seal, use the minimum sized slot and still seal...somewhat.

Are we looking to use Nstrike clips? if this thing can gravity-feed, why not use it as a hopper clip a la Quick16 (Drop darts in and move on)

Edited by Y-Brik, 25 May 2011 - 12:06 AM.

[Darksircam]

I did something similar a while back -
Using 1/2" PVC as the outside, you actually have a LOT of free space. I cut the CPVC slot 1 cm larger than it should have been and it still seals as well as it should.
I had some really weird PVC/CPVC that actually nested inside each snugly, so it has a good airseal.

The more size difference between the two pieces the more room you have for error.

This is brilliant. Might make my RF20 work again.

Edited by Darksircam, 25 May 2011 - 12:26 AM.

[Boot]

Interesting, this is the exact same concept that the Mirage 2.0 is based off of. The main difference is instead of electric rotation a simple slanted channel cut allows a longitudinal pull of just over 1/2'' to rotate the breech 180 degrees. By doing this the entire chambering action can be accomplished in the trigger pull.

I have actual built working prototypes of this, but have not had access to brass (or at least un-dented brass, which is the reason the Mirage 2.0 still isn't done, and won't be for a while). Even then with mildly dented brass and crude cuts friction isn't enough of an issue to make the trigger pull prohibitively hard.

It's good to see others are also experimenting with this idea. Definitely worth it to post it up!

[lordnikon60]

This is an amazing idea. I'm going to have to make one and see what happens.

[Dyxlesic]

Increasing the diameter of the 2 pieces of brass making the seal should increase the relative surface area avalible

If we glue the 17/32" barrel into a stub of 9/16" into which the dart can drop, and sheath that in 5/8", in theory we can have it seal, use the minimum sized slot and still seal...somewhat.

Are we looking to use Nstrike clips? if this thing can gravity-feed, why not use it as a hopper clip a la Quick16 (Drop darts in and move on)

I find Gravity fed tends to be somewhat unreliable. Besides, clips are way awesomer. Having a raider drum in something like this would be pretty beast

I did something similar a while back
Using 1/2" PVC as the outside, you actually have a LOT of free space. I cut the CPVC slot 1 cm larger than it should have been and it still seals as well as it should.
I had some really weird PVC/CPVC that actually nested inside each snugly, so it has a good airseal.

The more size difference between the two pieces the more room you have for error.

This is brilliant. Might make my RF20 work again.

But a greater size difference would leave space between them, removing the seal, if I am correct.
Thanks, for your rf20 I think you should do something like boot suggested, but over the full stroke of the rf20 piston instead of a trigger distance

Interesting, this is the exact same concept that the Mirage 2.0 is based off of. The main difference is instead of electric rotation a simple slanted channel cut allows a longitudinal pull of just over 1/2'' to rotate the breech 180 degrees. By doing this the entire chambering action can be accomplished in the trigger pull.

I have actual built working prototypes of this, but have not had access to brass (or at least un-dented brass, which is the reason the Mirage 2.0 still isn't done, and won't be for a while). Even then with mildly dented brass and crude cuts friction isn't enough of an issue to make the trigger pull prohibitively hard.

It's good to see others are also experimenting with this idea. Definitely worth it to post it up!

You say everything is based off of the the same concept as the mirage . Anyway, that's a really good idea. I'd love to see pics of your prototypes. The cut necessary to make The turning on the trigger pull or a back/forth motion seemed really hard to cut, as it would have to be curved and smooth, but really really precise.
Yea, as I said I would like to see others progress in this design. Everyone has thought of iv, just nobody has gotten it to work

This is an amazing idea. I'm going to have to make one and see what happens.

thanks. If you find out anything, post it up

[Boot]

hehe, the Mirage 2.0 concept is just a rotational breech as described attached to the valve system in the Mirage-ss. I've only ever brought it up when discussing feeding systems for semi-auto blasters (certainly not everything ). I do mention it a lot though, it's a project I am perpetually excited about. sorry.

Another note on rotational breeches is that they pave the way towards a completely different kind of blaster. Rotational breeches make crank powered blasters much more viable, and make designs based around circular rather than linear motion possible.

Also, I'll try to get pictures up as soon as school ends. Exams are next week so I am a bit busy now.

Edited by Boot, 25 May 2011 - 06:14 AM.

[Dyxlesic]

hehe, the Mirage 2.0 concept is just a rotational breech as described attached to the valve system in the Mirage-ss. I've only ever brought it up when discussing feeding systems for semi-auto blasters (certainly not everything ). I do mention it a lot though, it's a project I am perpetually excited about. sorry.

Another note on rotational breeches is that they pave the way towards a completely different kind of blaster. Rotational breeches make crank powered blasters much more viable, and make designs based around circular rather than linear motion possible.

Also, I'll try to get pictures up as soon as school ends. Exams are next week so I am a bit busy now.

Don't be sorry, I was just messin with ya. The mirage is pretty awesome, and I've been obsessed with designs and projects way too much in the past too. post whatever you want on it here as to help us all make the best toy possible

As for the rotational idea, I have done HUGE developments, none of them utilizing this system, as I have found a better system for a rotating mechanism.(not saying this can't be used, as it can be used great, I have just found what I believe to be a better way. I will post when I get the chance. If you like my 2nd grader type diagrams, you will love my 3d cad designs I have made. Please don't ask me about it in this thread, as I will post a full one for it shortly.

Yea, i feel your pain. I've been busy with exams and makeup work too. Almost done tho, so I will post the rest pretty soon. Can't wait to see your pics

[Dyxlesic]

Alight, sorry for the double posts. My computer is having mental problems, and I'm using my iPhone for everything, and doing an edit on that is a pain.
Here is a quick diagram of the wiring for the automatic setting

Wires are a bit disorganized in this pic. If anyone needs it I can make a more organized diagram of it. What it does is fire when the trigger is pulled, but always en in the open position

[shmmee]

I had a very similar thought a year or two ago, completed a prototype, but never posted anything about it. I eventually abandoned it because it was very tough to get a seal along the vertical seams.

My version uses a piece of pvc with a spiral cut channel (kinda tough to see on the vid, but I tried) to Gap a spur on the rolling breech and rotate it as the pvc passes over the breech. I also had to have a 1/8" guide bar running along the side to the breech rotates instead of the pvc. There is a bit of a friction issue (I re-lubed with silicone spray, which made the pvc difficult to hold on to.), but it has been sitting in my parts bin for over a year.

Here's a quick video I shot before running out the door to work this morning. Pictures would provide a poor explanation of function.
Click it to open and play it


I started off trying to rig a string around a bigger collar. My thought: pulling on the string would pull on the collar, which would rotate the breech. I set up a collar that sat 1/2" above the brass sleeve to increase leverage, but friction was still too great. I really had to yank on it. I sadly doubt you'll have much luck getting it to roll via motor. Reduce friction by keeping your rolling breech as short as possible. You'll have to put a very large gear around the outer breech, and a very small gear on your motor.

Failures of my method:
-Hole in breech is only big enough for crappy thin Lowes foam.
-Seal failures along vertical seams. (made worse by miscalculated tuning attempt. It used to fully close, but I moved the spur to add the brass guide rod, and moved it too much. Now it "closes" with an 1/8" gap in the bottom.)
-Sliding pvc would run over N-strike clip fingers. Increasing the length of the sliding breech and spur forward (ahead of clip fingers) would dramatically increase friction. (Which is already kinda high - even with only 3/8" overlap on the front and back.)
-Takes a lot of brass. You need to sleeve over your barrel (at least as far forward as the pvc slides) so don't have a transitional thickness for the pvc slide to catch on.

Successes of this method:
-Proof of concept
-Um, looks impressive?

Yeah, that's why I abandoned it and put it in my parts bin.

Edited by shmmee, 26 May 2011 - 09:16 AM.

[taerKitty]

I had a very similar thought a year or two ago, completed a prototype, but never posted anything about it.

Primarily, I posted to say that your avatar is perfect for you.

However, if you're willing to have a thicker and non-coaxial inner barrel, it might work. The outer barrel can be thin - all it need do is provide a seal.

However, the larger it is compared to the dart, the smaller the relative arc is needed to be cut away to accept the dart.

In other words, if you have an outer barrel that is slightly larger than the inner barrel that is slightly larger than the dart, you'll need to cut away roughly 1/2 the pipe.

Now, imagine, for sake of ridiculousness, a 1" outer barrel. A feed slot for a 1/2" dart would only be roughly 1/4 the pipe. The inner barrel is non-coaxial, meaning it is a 1" solid cylinder with a 1/2" pipe that is against one edge of it - not co-incident, but offset just enough so that 1/2" pipe has a solid wall.

[T3K]

Nice idea but may I suggest a drive belt instead of to rubber wheels (those are wheels right?).

Only thing is, hoppers clips are now cheaper than NStrike clips.

[PVC Arsenal 17]

This is an excellent idea. I considered experimenting with it after I made the ARchangel but I just didn't have the time. If you could guarantee reliable feeding, this could allow some respectable rates of fire. My original thought was to synchronize the breech rotation with a solenoid valve just like my ARchangel, only this wouldn't require such complicated coding - you don't actually need continuous rotation; a strong servo sweeping back and forth 180 degrees would work just fine. Most popular uC platforms have prewritten library for servo pulses as well. There is definitely some potential here if it can be done right and I look forward to what you guys come up with.

[shardbearer]

This is a really nice idea, I think using CPVC as the inner material would help with the sealing issues because it is a good bit thicker than brass, which would help for the reason Taer mentioned. With a bit of sanding on the outside, it fits nicely inside PVC. And it would probably be better to rotate the outer pipe rather than the inner one, because then you could continue the inner pipe forwards and make it the barrel.

And Dyxlesic, it would be appreciated if you took screenshots rather than pictures of your computer.

[Dyxlesic]

This is a really nice idea, I think using CPVC as the inner material would help with the sealing issues because it is a good bit thicker than brass, which would help for the reason Taer mentioned. With a bit of sanding on the outside, it fits nicely inside PVC. And it would probably be better to rotate the outer pipe rather than the inner one, because then you could continue the inner pipe forwards and make it the barrel.

And Dyxlesic, it would be appreciated if you took screenshots rather than pictures of your computer.

I think the cpvc's walls are too thick, and will shread the second dart in the clip in half as it loads the first one
I would love to post screenshots, but my computer has been having mental problems lately, and isn't working.

Shmmee, you are a genius. the revolving has given me a great way to change the layout of this.
When firing from an open bolt position, you get a slight lag between trigger pull and the actual firing. However, when using a closed bolt position, it reloads after each shot, so if you empty a mag, you would have to fire an empty shot for it to rechaimber. A similar problem exists with real guns, as once you fire your last bullet, you have to pull a priming bar back to rechaimber. Using shmmee's idea, i could have a priming bar that would hit a switch disabling all electronic function (so it wont try to readjust itself), and rotate the breech 180degrees, rechaimbering the next dart. While with any standard clip fed system, double priming will result in a jam unless an ejection system is used, this will not happen on the halfpipe breech. Does this make sense or would anyone like one of my super fabulous visuals?