370 replies to this topic

[Flaming Hilt]

Here you go. It closes as you pump back and stays closed when you pump forward. Of course, there would have to a fingerhold so you could open it for reloading.

The last one says "Fwd - Closed..." yea I'm tired.

Granted, not drawn to any scale; the tab might have to be forward or back on the pump; etc. But you get the idea.

I hadn't meant actual pulleys, I'd just meant a system with string. But you're right. Iono. I guess. Maybe. Kinda.

Edited by Flaming Hilt, 31 October 2006 - 07:52 PM.

[Ronster]

2: Where am I going to find a set of gears that small and how am I going to keep them in place should the gun be dropped?

2.1) This is what's gunna pull us down. Either we gotta make 'em, or... who knows where we're gunna buy 'em. Maybe we could fiberglass reinforce Legos...

That's it!
No I'm not saying to actually use Legos, but they worked for my prototype.
They're small and lightweight.





They actually come in many different shapes and sizes.

[friendly nerfer]

Did you come up with the shape of the gun by yourself or was it a star wars inspired idea?

[Meaker VI]

friendly nerfer, I'm pretty sure that the design is by no means finalized, so there is no way that it is based on something from Star Wars. Right now they're working out how to get the darts to load using a carrier and bolt.

Back on topic, I've been flipping through this topic since it started, I'd like to help but it seems you guys usually figure things out. The only thing I can think of right now is that you could use, instead of grears, levers or cranks to accomplish the same task. A largeish tab on the carrier that is behind another tab on the bolt would force the carrier to raise when the bolt was back and lower when it came forward, but your timing may need to be different. You would also want to make sure that the bolt's travel was stopped before the force transferred to these tabs, since that would destroy them.

While I think gears are totally possible on something like this (even using K'nex or Lego gears), I think they might be more of a pain to get to work right, since they do not have good variable motion (i.e.: they won't bring something up, hold it there, then put it down after the other part it's attached to has moved some; they'll just bring it up and put it down at the same speed).

[SHADOW HUNTER ALPHA]

friendly nerfer:
I've never seen Star Wars, so I can safely say it was an idea that I worked on as I went along.

Ronster:
Those Lego gears actually might work. I have to give some thought to finding the right type, but it looks like something in that picture will work. I'm not discounting Meaker VI's suggestion, but I just think it would be easier to have a system that I've seen be proven reliable.

Meaker VI:
I acually need all the help I can get figuring out how to make a removeable receiver, so if you had any ideas, post them.

Flaming Hilt:
You may need to explain your drawing a bit. I see that the pump pushes a peg of some kind back, but that's it.

[Ronster]

Those Lego gears actually might work. I have to give some thought to finding the right type, but it looks like something in that picture will work. I'm not discounting Meaker VI's suggestion, but I just think it would be easier to have a system that I've seen be proven reliable.

If I can find my Lego gears by this weekend, I'll see if I can make a working prototype including a bolt, mag, shells, and carrier assembly (the prototype I had made before was just to test the carrier design, not its compatability with everything else).

[Flaming Hilt]

The pump has a peg permanently attached to it that pushes back the breach door when you pump back. So the thing on the pump is the peg, and the door is... the door. For the rest, you can just look at the picture.

[SHADOW HUNTER ALPHA]

Flaming Hilt:
Maybe this would be easier if you drew a diagram that shows the pump, peg, etc. in relation to the parts it affects and the parts around it. (Like I did for the carrier.) I understand that the pump pushes the breech door shut, but where is this all in relation to the surrounding parts?

Ronster:
How the hell am I going to repay you for your help and opinions on this topic? First, you explain the carrier system, and now you're building a model? Where do you get this kind of free time?

[Flaming Hilt]

Well, just like @ howstuffworks.com. The breach door, when closed, is directly underneath the carrier. The pump is... well, it's where the pump it. I can still draw a picture if you like.

[Ronster]

Well, just like @ howstuffworks.com. The breach door, when closed, is directly underneath the carrier. The pump is... well, it's where the pump it. I can still draw a picture if you like.

I always thought that the carrier was the door for the mag breech on the bottom.
At least, that's how it is on a real shotgun...

Ronster:
How the hell am I going to repay you for your help and opinions on this topic? First, you explain the carrier system, and now you're building a model? Where do you get this kind of free time?

Well, I said I'd try.
It's been a while since I've picked up my dremel with all this school work, not to mention taking all the time after school and memorizing lines for the play I'm in. So, if I can find time, I'll do it.

Oh, don't worry.
Just some credit when the gun is made would be nice

[SHADOW HUNTER ALPHA]

I think I see what you're talking about, Flaming Hilt. This may not be exactly what you saw, but there is a downward bulge on the slide, which is colored light blue. I think that this could be the answer, since it is enough to just block the top of the shell from exiting the magazine when the pump is in its forward position.

Ronster:
Of course I'll give you credit. Everyone who helps me here will be given due credit. I don't believe in taking help without an honest announcement about it, so if there's a favor I might be able to do in return (I.e., some high-quality stefans once this gun is done), just name it.

[tcorr911]

I'm also planning to make a shotgun and I am going to use the plunger in the scar-n and the bolt in the far. All the trouble that I am having is getting the shells in the tube clip to the bolt, I just think that if I just used a carrier the shell would just slip off, so I'm thinking of a ramp with a carrier going through it so the shell would even out. It will probably not slip, I think.

Edited by tcorr911, 07 November 2006 - 12:48 AM.

[SHADOW HUNTER ALPHA]

tcorr911:
If you look on the howstuffworks page mentioned in the earliest couple posts, you will see that there is either a bump or a ledge on the carrier that stops the shell from sliding all the way back. That stop is placed carefully in a spot where only one whole shell can be on the carrier at a time. I think this could be the solution, becuase I myself was considering it for simplicity.

P.S.: For all of you out there who are either working on or want to work on a Nerf shotty, P.M. me. If there are enough of us, we might be able to walk each other through the design and construction phases.

[tcorr911]

OK I get it, but if you have the bolt lift the carrier up, won't the shell go down before the bolt reaches it?

[Ronster]

OK I get it, but if you have the bolt lift the carrier up, won't the shell go down before the bolt reaches it?

That's what the gears are for.
They allow the carrier to be lifted right before the bolt closes. It's kinda complicated.

Don't worry guys, I have been extremely busy these past couple days. So, I'm still working on that model.

Edited by Ronster, 07 November 2006 - 09:59 PM.

[SHADOW HUNTER ALPHA]

tcorr911:
Actually, the bolt's side keeps the carrier dog depressed while the bolt is sliding forward and back. The bolt's contact with the carrier dog is stretched out in duration so that by the time the carrier dog is released and the carrier falls, the front of the shell has already been pushed forward and the rear of the shell is supported by the front of the bolt. I haven't got the exact specs down, but if Ronster can complete a working model (no pressure, Ronster), then it will be much easier to explain. The howstuffworks page isn't too good for the animation of the unit, so you don't get the exact idea enough to see what happened in between the steps. It kind of took me a while to get that one, too.

[tcorr911]

Oh, I thought it was directly attached, now I can get some work on it.....soon.

P.S. has anyone found a long enough and weak enough spring for the tube mag yet?

Edited by tcorr911, 08 November 2006 - 06:46 PM.

[SHADOW HUNTER ALPHA]

I'm still working on the mag tube spring. The problem is going to be finding one that's between strong and weak, and between long and short. If it is too long, then the spring might stick out into the carrier and get all screwed up when the carrier rises, and it won't be small enough when compressed all the way. Short springs won;t be able to push all the cartridges out. A strong spring can inhibit feeding due to tension, but a weak one won't have the force to empty a full magazine. I can probably find some springs at Home Depot or Lowes, but I'm not sure. If anyone sees any, tell me where they where they were.

Edited by SHADOW HUNTER ALPHA, 09 November 2006 - 05:54 PM.

[Meaker VI]

Right now I'm thinking that the mag spring isn't the biggest problem. I'm more worried about how to get the feed working, which requires desigining a bolt that will interface with the dart when the carrier is at the top and push it into the chamber. Though finding the mag spring would allow figuring out whether we can get away without shells or not (I'm a fan of shell-less construction).

[SHADOW HUNTER ALPHA]

I know shells may be tricky, but they're the only way to load the darts into my gun while ensuring that they don't get bent (which would play hell with my range and accuracy tests, not to mention mess up my feed mech and bolt design). As for the bolt, I was thinking along the lines of a cross between boltsniper's SCAR-N rotating bolt lockup and the bolt illustrated on the howstuffworks page. If the cam pin is moved by the operating rod, then the design is simpler than one might think. As for the mag spring, that's not my top priority. I want to make sure that a receiver and bolt can be built before I invest more time and money in a project like this.

Edited by SHADOW HUNTER ALPHA, 10 November 2006 - 04:00 PM.

[anders]

Okay I have a idéa. You can begin with the buzzbeetoys rapidfire rifle. And then you can do this :


If you know how the rapidfirerifle works you should understand my pic. The yellow thing on the right is the yellow rod that comes out the back of the rifle when you cock it. And the big black thing under it is the carrier which has a spring attached to it that is forcing it uppwards. And when the yellow rod goes forward to push the shell into the firing chamber the thing attached to it's underside pushes the carrier down and then it repeats. The only problem is that the plunger and that stuff is were the pumpaction shot gun magazine would be .

Edited by anders, 12 November 2006 - 03:53 PM.

[Meaker VI]

Actually, I don't see any kind of problems with the idea behind that design. The only thing I would change is the placement of that catch on the bolt/plunger assembly and get rid of the spring so that the carrier would rest in the down position and be forced up by the pump cycle. It would facilitate loading to not have that spring there, since you could force the carrier up to put additional rounds in.

I've figured out how the design I was discussing with Shadow Hunter would work, which is very similar to that except that it has a 2 lever system which would be more complex. The carrier dog (a small tab attached to the end of the carrier via hinge and anchored with a rod through it's center) would be passed over by the bolt (making the carrier go down slightly) and then on the return stroke of the pump cycle engage a catch on the bolt forcing the carrier up (the carrier also having a rod through a rotation point somewhere along it's leingth). It would give a greater flexibility in the adjustment of the timing of everything, which is critical to get this working. But if it's unnessecarily complicated, then anders' design sounds like it would work fine.

[SHADOW HUNTER ALPHA]

It would be easier to remove the spring there, since the design would have to be top-loaded through an extensive amount of force, and the shells could easily get caught if they are put down crooked. As for Meaker VI's design, I think I understand the concept that you have there, but it would be much easier to have a detail pic for reference. Once that's up, it will be simple to tweak the entire gun's design to accomodate the loading system that is best. I still like the gear design, though, because it has been proven to work until someone builds a working model of this lever system and an effective test for how long the device can function without jamming.

[munson20]

Have you begun the shotgun yet? Im really excited to here about it, or see it!

[LastManAlive]

I'm not putting a ton of money into mine, so I'm just waiting for the springs and parts to appear for me. Literally.

But so far, I have the actual spring for it, most of the PVC for it, I THINK I will use the spring out of the reactor for the resivour. Other than that, I have a boc of springs for action springs that I got as a stocking stuffer for christmas. The only amount of money I will put into this is for paint, but I need that for another gun of mine as well.