78 replies to this topic

[Greek Assassin]

Right now I'm working on an Mp5 version of that rifle. I'm also working on a steyr scout loser rifle that uses the same type of extraction/ejection method, but uses air power and brass shells.

Edited by Greek Assassin, 08 April 2005 - 03:23 PM.

[pigeon4]

I'm not really a fan of either gun, but I've got to ask, what are you going to put at the base of the shell for the bolt to grab onto?

[whatiam]

The bolt is simply used to pull the breech open.

[pigeon4]

The ejector and extractor are part of the bolt. When the bolt slides forward, the extractor grabs the shell. Then, when it is pulled back, the ejector flips the shell out.

[Greek Assassin]

I put 1/2 inch pvc on the back of the shells. The entire bolt mechanism is based on 1/2 pvc and the barrel is made of 9/16 brass. Each shell is made of 17/32 brass so the front end of it fits snuggly in the barrel.

[pigeon4]

Sounds good. I'll like seeing the finished product. For the sharpshooter configuration on my XM8 I'm going to have a CPVC barrel and use the standard PVC shells with nested CPVC. The normal configuration will fire megas though.

[GeneralPrimevil]

The bolt is simply used to pull the breech open.

Bolt handle. And it opens the chamber. The breech is the second rearmost part of a barrel, just before the chamber. So it goes chamber -> breech -> rifling -> crown. This barrel has no rifling, so it's the fired bullet guide (smoothbore).

The ejector and extractor are part of the bolt.

The extractor and ejector are parts of a part of the bolt. The part of the bolt I am speaking of is the bolt face. However, some horizontal sliding action designs call for a different style of bolt, so the ejector is part of the bolt directly. On boltsnipers gun (the one I am talking about now, not casing weaponry in general), it appears he does not have a bolt face as a seperate piece. It is integrated into the bolt body itself, as a one piece unit. It is easier to make without the use of blank stock to machine two pieces.

pigeon4: XM8 trio. So you're going to have only one bolt face, but use smaller stefans for a better ballistic coefficient, resulting in higher velocities, increased range, and increased accuracy? Sounds interesting. I take it all you will have to do is unscrew the large bore barrel and screw in the smaller one. If you really wanted to crank out the range, a boat tail and spitzer style point would do the trick. Just sculpt the rear of a stefan and point the front with hot glue. Just don't make it too sharp.

It's kinda funny how boltsniper has created a cult.

[Greek Assassin]

I guess he really has created a "Cult".

[GeneralPrimevil]

Greek Assassin: Which reminds me (somehow) that I PMed you something that may help you in the brass casing department for your MP5 version of boltsniper's magazine-fed fast-action nerf repeater.
And how well is everyone else doing on theirs? I'm starting to think that I want to make one also, but again with a different design basis and different build materials. But I will wait til the scrap metal yards open here so that I can make the thing weigh fifty pounds. That and I need to finish another project first (a dead topic started by me two days ago), which involves finishing another project before that (wich is another dead topic, by me yesterday). But anyway, so far there have been assault weapon cosmetics chosen, so I will represent the non assaults. I'll show you what I mean by this. The M82, not the M16. I'd probably go with regged CO2, or some other higher pressure gas source, on a remote hose for that beast, instead of spring power. Then again, I want it to be the full 6 feet in length, so it needs high volume pressure to get the darts through the barrel (29"). Otherwise, cosometic construction is easy as all the body is is 1 1/4" PVC. I have started it. I have a few casings made, a T-tubular muzzle brake, the mag is designed, so is the magwell, and the bolt is almost done. All that has to wait for the scrap yards is the magazine itself, the magwell, the firing valve, and the ejector. Same with the carry handle and bipod, which I might omit for sake of simplicity.

[pigeon4]

Thanks for the tip with the stefans GeneralPrimevil. The barrel will be attached with screws instead of being glued in as on boltsnipers. The advantage of this is like the actual XM8, my nerf version can be almost as customizable.

I wouldn't necessarily call this a cult.....I think he's just started the revolution. I mean, if a lot of people start useing fast-action magazine fed guns, it'll change nerf forever.

[GeneralPrimevil]

I got another great idea before I fell asleep at 2 in the morning...again. I figured out how to keep the pressure in my homemade higher than normal for a longer (30"+) by using a combination of spring power and an air source. I also found a doable way to make a mag-fed the size of an M82 to be semi-automatic. No shit there. The problem is, I don't know if I can make a valve that precise in cuts and drills unles I get another drill press. But it relies on a three way valve, one for pushing back the bolt, the other for filling the firing chamber, and the third as an inlet which. Depending on were it is in relation to the valve's body travel, the in will be filling a piston for the bolt blowback, the firing tank, and both at one short time in comparison to the other stages. Unfortunately, it requires some very precise components so the bolt doesn't blow back just before the rifle fires. It's kinda like a 'Cocker's pneumatics, only made of hardlines instead of braided steel. I'll post a MS Paint enhanced sketch once I wake up. This will not be found on my first rifle, as it is too complicated for a "well let me see if I can build this" experiment.

So this may not be a cult, unless someone shaved their head with the silhouette of his rifle. It does have quite the following, however.

Well progress on my rifle is great, I will skip the two-piece bolt in favor of having the bolt face be a washer to limit the movement of the ejector and to allow a groove to be milled for an o-ring. So the bolt will be more traditional to boltsniper's original, unlike everything else on this rifle. I also am using rimless casings, as they take up less space. The problem is getting all the rim grooves turned to the same specifications. I might just make a cutting guide which slips on the end of the casing blank and mark the flute line. I also will be using a standing ejector, unlike the plunger ejector found on boltsniper's. That is simply because I forgot about the sprung plunger ejector when I ground the bolt.

Edited by GeneralPrimevil, 09 April 2005 - 09:14 AM.

[NJNerfer]

Ok I am going to try and compile a list of all materials needed. There are some I may be missing. I want to get everything together before I start on this. So here it goes...

1) 1 and 1/4" sch 40 pvc
2) 1" 200psi* pvc
3) 1/2" sch40 pvc couplers
4) 1/2" sch 40 pvc
5) the airsoft spring foundHere
6) Carbon Rod**
7) Balsa Wood

I dont know the other materials needed. I also dont know the lengths of the above materials, so any help would be appreciated...




* what does this mean?
** where can i buy this or what can i put in place of it

Edited by NJNerfer, 09 April 2005 - 09:15 AM.

[Greek Assassin]

200psi pvc (Also known as sdr 21 pvc), has a thinner wall and a larger inner diameter.

[boltsniper]

Ok I am going to try and compile a list of all materials needed.  There are some I may be missing. I want to get everything together before I start on this. So here it goes...

1) 1 and 1/4" sch 40 pvc
2) 1" 200psi* pvc
3) 1/2" sch40 pvc couplers
4) 1/2" sch 40 pvc
5) the airsoft spring  foundHere
6) Carbon Rod**
7) Balsa Wood

I dont know the other materials needed.  I also dont know the lengths of the above materials, so any help would be appreciated...




* what does this mean?
** where can i buy this or what can i put in place of it

I`ve tried to remain out of this thread because it is interestingg watching everyone discuss the design points of my rifle. Most of you are picking everything up nicely. I`m glad to hear that so many are attempting a homemade inspired by mine...wheter a carbon copy or not.

Just a few clarifications:

The spring is NOT an airsoft spring. If anyone says that again I will slap them. The spring I used is a rifle length AR15 buffer spring.

Joe, the spring is fully compressed when the bolt is retracted. Yo can also use a carbine spring which is about two inches shorter. Performance drops slightly as one would think.

Pigeon4, the barrel on my rifle is attached with screws to the receiver and can be removed. I`m not sure what part you think is bonded. That chamber is bonded to the end of the barrel. I did this to keep the number of components down and also to permanantly set the headspace which is semi critical in the rifle. If I ever convert the rifle to different propulsion system like CO2 I would likely build a longer barrel to accompany it.

Greekassasin is right on about the 200 psi 1" stuff. You need to use it to fit the 1/2" couplers inside it.

Carbon rod can be ordered from a few different places on the internet. Just search "carbon rod", or "carbon fiber rod" etc. You cold definitely use wood dowels in place of the carbon stuff. I don`t foresee a problem with that.

GeneralPrimevil, Your project sounds pretty sweet. If you plan on usig the thign though you might want to tone it down a little. If you are going to make something that powerful you might as well make a pintball or potatoe rifle.


PICS. I want to see what all this stuff looks like. POST PICTURES!

Edited by boltsniper, 09 April 2005 - 10:43 AM.

[NJNerfer]

sry bout that

[pigeon4]

Pigeon4, the barrel on my rifle is attached with screws to the receiver and can be removed.  I`m not sure what part you think is bonded.  That chamber is bonded to the end of the barrel.  I did this to keep the number of components down and also to permanantly set the headspace which is semi critical in the rifle.  If I ever convert the rifle to different propulsion system like CO2 I would likely build a longer barrel to accompany it. 

Oops, I don't know what I was thinking. I gotta start drinking coffee when I stay up that late. Very sorry, for my mistake.

[GeneralPrimevil]

I've decided to skip the repeater, for now. Straight-pull bolt action single shot. I also skipped standard style ejectors on the new bolt I had to make. Now I have a push button ejector hole in the side of the upper receiver. It will still have a magwell and feed ramp though, just in case I wanted to install a mag later. I've decided that about 90-110 psi should be good for what it will be used for. The people I nerf with don't care about pain. It builds character. However, safety is still a concern, and we'll see how it does when it's finished. Maybe it won't be that powerful. It will fire mega stefans, so the frontal surface area of the projectile should compensate for higher velocities when it comes to penetration, with lack there of as the goal. Oh yeah, boltsniper, how much pressure did you run your first homemade at? The CO2 bolt action one?

[Greek Assassin]

I used to modify water guns before i got into nerf, and if i remmber correctly, about 150psi was able to create a stream of water powerful enough to sting from about 60ft. Imagine what 100psi could do with a stefan! Just make sure that you only use your best stefans with that gun, otherwise any imperfection in the dart could severly diminish proformance(sp?).

Edited by Greek Assassin, 09 April 2005 - 04:13 PM.

[NJNerfer]

proformance(sp?).

Performance...

BoltSniper: the springs you used for the bolt action and trigger... are they found on the site you mentioned earlier as well? or is just the plunger spring on that site?

Edited by NJNerfer, 09 April 2005 - 05:14 PM.

[GeneralPrimevil]

Well my mega stefans are a 1/16" too big for my 5/8" PVC, so the tight fitting dart probably doesn't help any with the safety of the whole thing. I am going to go the Nerf route and include mounts for air restrictors if need be. This rifle will be firing its first battle shots in May. Or at least that's when I need it done and working perfectly by. I have plans for making three of these now. A bolt-action (15 degree throw) single shot (current), a bolt action (linear pull) repeater, and if I can afford it, a semi-automatic (pneumatical blow back) carbine. That is essentially a chopped version of the M82, using smaller casings designed for micro stefans. That one probably will not leave the sketches sitting on my counter. Unless I designed it on what I just thought of 3 seconds ago, which is to use excess gas from the barrel, not from the HP tank. I'll figure out a few pressures, then decide on whether to adapt my current rifle to test it.

This homemade based on a homemade has had the most thought of all my mechanical/pneumatical designs ever. I think boltsniper jumpstarted my brain. I hate it when that happens.

[NJNerfer]

arlight I have taken boltsniper's pic of the gun taken apart and tried to assess what all the parts are. correct me if I am wrong.

[boltsniper]

Close NJNerfer....

Here:

[GeneralPrimevil]

So what exactly did you base your homemade off of boltsniper? Or did form follow function?

I belive the aesthetics of a piece should be linked to the operation of itself. That is why I have added several design elements to the M82A3 base. I have redisigned the handgaurd, muzzle, and stock to better suit nerf. I will be done within two weeks and pics will be posted after next Wednesday, as that is why I am going to Home Depot, Lowes, Menards, and a few scrap yards. Thursday will have in progress pics taken and posted. The following weekend shall have the finish of the rifle with the rest of the week trouble shooting and testing, along with accurizing of the rifle (further action lapping, leaks repaired, etc.)

[boltsniper]

Form follows function. Everything on the rilfle is there for a reason. I had no particular shape that I was shooting for during construction. In order to get a well proportioned rifle that would be comfortable to shoot I took things like length of pull, chargin handle location, pistol grip location and angle, etc into account during design. Other than that components like the receiver cover spawned purely from need to fulfil a function.

I look forward to seeing your projects.

[GeneralPrimevil]

I think I just realized something very horrible that I seem not to have noticed before. The valve I am using to fill the tank can't work in the space provided. I may have to use electromagnetic force and a small 12VDC solenoid valve found in International school buses. If I screw up on it, I'll still have about twenty left*. That way I can route wires instead, with a small momentary switch attached to the trigger. Should I swap out the firing valve with the same (upscaled valve) thing? Or should I skip electricity and make the lower receiver larger (more like the real deal M82) to accomodate the valve which was my first post/topic on NH (quarter-inch in/out, 1/2" is for the firing)?

I just realized that the design element I had been building to regulate the pressure throughout the barrel length will increase pressure in the tank. That means I could either use about 50-60 psi or I could get rid of the expansion pressure reg all together to use 90 psi.


*I have access to all of my school system's old bus parts. Pretty much, whatever they are going to throw away, I have first dibs on. You better believe I have a folding stop sign.