370 replies to this topic

[Carbon]

It's possible to use FBR as a seal...DavidBowie used some as a plunger seal and got good results, so it may be a good candidate for what you need. It'd offer some cusioning as well, which would be a plus.

[Commonly Hunted]

Thanks for the reminder, Carbon. Forgot about that.

Ronster, I have a 12" section of 17/32" brass for the barrel. The long thing was the outside for cosmetic use only.

[Pineapple]

Here I am again, just checking in...


We're fast coming around the 1/2 year mark that this thread has been in existence. The fact that it has been posted in with (relatively) useful information shows that there is some interest in this project.

It seemed to have some promise, with several of you actually building some concept protos and running the moving parts through their paces, finding out what worked and what didn't.

But now it seems like everyone is just watching Commonly Hunted, and throwing ideas and advice, without anyone else actually making something and doing some tangible R&D. It's kind of turning into Commonly's project now (which by the way, did you finish all your Boltsniper replicas that others had asked for? I remember Cole wanted his F.A.R.).

I'm going from skeptic, to cheering you on to finish something. At least y'all are forging ahead. That in and of itself shows that this project must have some merit to it. Good stuff.

Don't give up, any of you. Make some'tin.


-Piney-

[Commonly Hunted]

I have been working on the shotgun so I can graduate early and haven't been working on the Bolt guns. Those are to be made whenever I give up or finish the shotgun's lab report (which is five weeks overdue because of loss of power or tools).

Anyways, I tried the new stefans and they aren't working. They get to about 1 or 2 inches from the end of the barrel and stop. Does anyone use spray lube in the barrels? I was wondering if that would help.

Also, everything is the way it used to be when I had it shooting, and now nothing. I just don't get it. Still haven't tried the foam circle for behind the bolt carrier. Got to buy some craft foam first.

[Flaming Hilt]

But now it seems like everyone is just watching Commonly Hunted

Moving+Work+Aunt Died+AP Tests soon+Rest of School+Gf+Dad is an a$$+other minor variables

=

I'll get to it eventually. I know I keep saying that but that's because it's true. Until I get started, though, my cheers are still for CH.

CH, sounds like your barrel is probably too long. Go here and get your active plunger volume and divide by four or five and if your barrel is longer than that... it's too long.

Don't lube the barrel. Lube is for plastics... like O-rings. Actually, I have verbal confirmation Carrtoon doesn't even use lubrication. Don't use lubrication.

Don't use craft foam or FBR. Use pipe insulation. No slot where two halves connect -- it's round by nature.

[Commonly Hunted]

What kind of link you got there, Hilt? Does nothing when I click on it.

And by pipe insulation do you mean that stuff that is like FBR but many times bigger?

How does Cartoon get his plunger to move without lube?

[Flaming Hilt]

1. http://www.1728.com/diam.htm

2. Yea, and has a hole in the middle. It goes around pipes to insulate them. Thus the name, "Pipe Insulation."

3. All plungers will move without lubrication. You really only need lube if something won't move in the first place.

[Commonly Hunted]

Back again.

These are the same pictures I'm about to send to my Physics teacher for my Science project. I still haven't gotten it to work but I don't care for now because he said I could write a lab report without having a working shotgun. Also, I really want to get back to making the Boltsniper games for you guys.

The barrel. The electrical tape is where the 17/32" is nested in the 9/16" brass. The ends are .5" PVC for support inside of the barrel sheath.


The bolt with the bolt carrier. The e-tape there was the temporary seal.



The bolt by itself.



The barrel sheath. Made of .75" thin-wall PVC and the outer chamber is 1" thin-wall PVC.


The outer chamber. The inner chamber is the 9/16" brass on the barrel, by the way.


The shell and the 1.5" stefan. This is the one that actually fired.



The body. Made of 1.25" PVC and is also the plunger tube and has the catch guide in the back.




The plunger. Has the NTS-style catch just so it works. I really wanted a full around catch.


The main spring and wire catch. The spring is half of an AR-15 spring.


The bolt-shell-barrel assembly.



The rotating bolt and outer chamber interacting.

Edited by Commonly Hunted, 23 April 2007 - 10:58 PM.

[Prometheus]

Yeah, I'm gonna say that plunger stroke is too short for your barrel, Boltsniper used a full length AR spring, but just my opinion... oh yeah, what did you end up using for the seal around the bolt and bolt carrier?

Edited by Prometheus, 24 April 2007 - 08:16 AM.

[Ronster]

How well do the shells eject?

[Commonly Hunted]

Promy, here are some comparisons:

My shotgun
plunger travel= 3.5"-4"
plunger tube ID= 1.34"
barrel length= 12"

Ompa's Rifle
plunger travel= 5"
plunger tube ID= 1.34"
barrel length= 14"

Boltsniper's SCAR-N
plunger travel= 4.5"
plunger tube ID= 1.16
barrel length= 12"

This shows that they aren't much different and should be somewhere near each other in ranges. My shotgun just doesn't have the best seal and so only got ~30'. The seal is still just the e-Tape since that at least got some range. Although, that doesn't work now either.

Ronster, the shells don't eject because this shotgun was just built up to the point where it could fire. Nothing more. I am hoping to get back to this design during the summer. For now, I'm done with this.

[Ronster]

Aw, that's a shame.
I wanted to see how you might have solved the problem of how to get the extractor and ejector in such a tight place...

Oh wells.
Guess we'll have to wait for summer.




Oh! I almost forgot.
It's been a while since I've contributed my share to the thread.

I've come up with a new idea (easier idea) for the carrier to lift without gears and such.

I'll have to find a way to explain it easier, though...

Just wanted to let you know.

[NerfFreak]

I'm incredibly sorry to bring back such an old topic. But I need some answers, as I'm designing my own shotty as well.

What size brass did you use for the breech, bolt, and any other part of the gun that used brass. If I buy some 17/32 and some 9/16 brass, will that work?

[Dart Attack]

If I buy some 17/32 and some 9/16 brass, will that work?

Sure.

[Commonly Hunted]

I used the same sizes Boltnsniper did in his SCAR-N because the components were the same.

This is the schematic for the shell.


There is no schematic for the bolt so I cut mine to two inches and sized the extractor claw and ejector around the rim of the shell.

Be sure to post your designs so that me could help you even further.

And it is no problem reviving this topic which is less than a month old.

[SHADOW HUNTER ALPHA]

As long as this thread is still alive, Piney can't bust my ass for giving up. With my final exams less than two weeks away, it's getting to be the time where I can start doing something with this project. I commend CH for his work thus far, and encourage new participants in the thread to try this design.

I would also like to see how some of you have resolved or thought about resolving the problem with getting the carrier to rise at the appropriate time and not jam. My own design would involve a single part that makes up the entire carrier, but I realized that the carrier would fall back down before the shell could be even partially chambered.

[Prometheus]

Ronster had a design in mind for a carrier, he just never posted it yet. Perhaps if we were to obtain it, we would be able to have more feasible designs...

[SHADOW HUNTER ALPHA]

Ronster had a design in mind for a carrier, he just never posted it yet. Perhaps if we were to obtain it, we would be able to have more feasible designs...

Feasible? I'm close enough to knowing how to build this gun that the carrier is the only hitch in the plan. Once I figure that out, I can start getting materials/beginning construction

Edited by SHADOW HUNTER ALPHA, 20 May 2007 - 10:33 PM.

[NerfFreak]

Well, I figured since this topic is starting up again, I might as well post my idea for an ejector.



The black is the bolt, and is basically constructed the same way as Boltsniper's in the FAR, except brass tubing is utilized in the 1/2" PVC. Basically, when the shell is inserted, the brass is pushed back into the 1/2" PVC, and is under pressure by the compression springs while the shell is pushed into the chamber by the bolt. When the bolt is pulled out of the chamber, the brass can push the shell forward and hopefully out of the ejection slot in the side of the main reciever.

This is just an idea, and would require some precision dremelling, but is possible.

Edited by NerfFreak, 21 May 2007 - 07:26 PM.

[Prometheus]

Ronster had a design in mind for a carrier, he just never posted it yet. Perhaps if we were to obtain it, we would be able to have more feasible designs...

Feasible? I'm close enough to knowing how to build this gun that the carrier is the only hitch in the plan. Once I figure that out, I can start getting materials/beginning construction

Well, not that these designs aren't feasible, but that a simple, efficient carrier is used. Otherwise, it's a gun without a carrier, kind of like a car without a motor. Sorry if you mistook that, I was more referring to a feasible carrier.

[SHADOW HUNTER ALPHA]

There are a few problems with the overall design of that ejector, but the concept is pretty much correct. The spring-loaded piece (the actual ejector) that pushes the shell out would need to be only on the side opposit the ejection port. Otherwise, the system will push the shell forward and not out. There also needs to be a clamp, in this case just a small wedge of a smaller-diameter brass, fastened to the side of the bolt where the ejection port is. What happens is this clamp, or "lip," latches on to the rim of the shell, where the smaller-diameter brass is showing, and the shell is held in place. The ejector is depressed by the shell being caught in this lip, and will not be able to move the chambered shell. Once the bolt moves backward, and past the ejection port, the ejector no longer has anything blocking the shell from exiting, and the spring will throw the shell out of the opening when this point is reached. Picture from Boltsniper's FAR page:

[NerfFreak]

I understand your point, but mine is that if the shell is launched forward by my ejector, some sort of guide could almost ramp it out of the ejection slot, almost like a mini-ramp. Anyway, I'm just brainstorming ideas here, and might try a few different one's with my bolt. As for the extractor, I'm not so sure, but I think I'm going to try that of a real M4/M16, just like in Boltsniper's FAR.

Edited by NerfFreak, 21 May 2007 - 08:29 PM.

[SHADOW HUNTER ALPHA]

It is difficult to do a ramp-style ejection system in a shotgun because the carrier will be rising at the same time as the ramp will be required to pop out (I don't see how you could integrate a stationary ramp into the design and still be practical). Perhaps you could do a variant of Boltsniper's SCAR-N with the magazine well facing to the side of the receiver (like an FG42) or on top (like a Bren or a Vickers LMG) and have the shells fall out of the bottom of the receiver, but you would need a spring-loaded pad in the chamber to prevent the shell from being pushed back into that vacant space when the bolt retracts.

Edited by SHADOW HUNTER ALPHA, 21 May 2007 - 09:00 PM.

[privateer]

I just fabricated a boltsniper-esque ejector for my homemade. It's not even all that hard, just time consuming; it took me about 45 minutes.

I brainstormed many of the ideas listed here, and ultimately found bolt's to be the easiest. I used 3/16" aluminum rod instead of carbon because it was cheaper.

I strongly recommend you go with this type of ejector; it's not as hard as it looks. Trust me.

Good luck. Lord knows both of our homemades are going to need it.

[six-five-two]

...Don't expect Commonly Hunted updating his progress, he was banned in an Off Topic thread.