Halo 3 BR Replica

[LoneWolf]

Hi guys, I'm a sophomore at U of M's Engineering school, and am looking at starting a side project to help myself learn to use CAD programs. The project is this: from the ground up design a functional Halo 3 BR replica (at least the body, while I'd like to design the internals [if anyone can help with this I'd appreciate it more than you could know!] I might have to use high-quality aftermarket parts). Google seems to think that this has not been done before, so purchasing and modifying a gun ins't even an option, not to mention that that isn't the point of this.

The plan is to design every possible detail with maximum accuracy, use lore-accurate materials, and have it preform as well as possible. And by "every possible detail with maximum accuracy" I mean functional ammo counter on the little screen and everything! I already have ideas for this, I'll discuss later if anyone's interested. Performance wise, I want to create a gun capable of firing around 410 FPS with semi-auto and three-round burst firing modes. I also want it to be extremely accurate, as well as light yet durable.

Now while I know a bit about airsoft internals, I know that there are many of you with MUCH more experience doing something like this. So, I would GREATLY appreciate any advice anyone can give to help me make this possible! Right now I'm kinda in the dark as to how I'll have the parts manufactured after I CAD them up, and only have rough ideas on what to do for the mechbox and hop unit. Please feel free to discuss anything about this, from material selection to design concepts to internal selection, and thanks ahead of time!

[Husky]

If you want it to be light weight yet strong a polycarb be your best bet on the material

[bobbunny]

Well, if you want to go overkill, this is what I'd recommend.

Prommy 6.01mm TBB (Teflon coated)
ER-Hop
M120 or M130
Metal Bushings and Spring Guide
V2 Gearbox
A High-Torque Gearbox (You won't be going for Speed)
STANAG (M4) style magazines
Forward Wired with enough space to fit a nunchuck, or lipos
Metal Spring Guide
Metal Bushings
Standard Ratio Gears (18:1?)
Burst Wizard MOSFET (So you can get the 3 round burst)

Everything I can think of on the spot. Mind you, this isn't going to be cheap.

[deacon]

You Wouldn't be able to use a Famas as a starting point?

[X]

Using this model here are my first thoughts...

fc09.deviantart.net/fs41/f/2009/048/a/e/Halo_3_Battle_Rifle_by_martynball.jpg

If your going from the ground up. I would recommend using a P90 (V6?) gearbox. I would mount it in the rear section of the gun like a P90.

I would use an off the shelf 3 round burst MOSFET. Tap into the signal wire to count each burst. Kills two birds with one stone. Since the halo gun has no semi I would lock it into 3 round burst. If you want semi you would need a mechanical means of engaging the cut off lever. This should also close an electrical switch so you can distinguish burst and semi in your ammo display controller. You could probably get away with a circuit that watched the voltage drop when the motor engages to count shots, but I don't know how to make one of those. This could also prove unreliable when changing batteries.

I wouldn't use a starting point gun. I think you will need to do the receiver totally custom built to do it right.

Sent from my DROID RAZR using ProBoards

[snafu]

What version gearbox is used in a famas? Seems like that would be a decent fit, although the trigger isn't far enough forward..

Edit. I do agree with you X that the body wouldn't be usable but the gb may be a good choice.

[bobbunny]

Have you considered taking down a Tavor and using the parts inside that as a base? Seems like a good idea to me given it's bullpup configuration.

[X]

Jun 3, 2012 18:28:49 GMT -5 snafu said:

What version gearbox is used in a famas? Seems like that would be a decent fit, although the trigger isn't far enough forward..

Edit. I do agree with you X that the body wouldn't be usable but the gb may be a good choice.

Since he's needing a MOSFET for three round burst the trigger won't need to have any mechanical interface to the gear box.

I guess to me I don't see why you would buy a gun for the gearbox when you can just buy a gearbox.

Edit: forgot about the cut off lever if your using a v2. That first statement isn't entirely true. The v6 has a dual stage trigger which would be easier.. I think... Doing 3 round burst only would make it way easier. Pull out the cut off lever and never look back.

In regards to material I would definitely use a polymer of some sort. I would think the future of all weapons is moving away from heavy metals and towards stronger lighter polymers.

Sent from my DROID RAZR using ProBoards

[Blitz]

Buy a Polar Star fusion engine and strip the v2 shell off of it. Then you can make the body however you want and not worry about fitting a mechbox. You can even program 3 round burst and fps.

[LoneWolf]

Jun 3, 2012 18:19:59 GMT -5 X said:

I would use an off the shelf 3 round burst MOSFET. Tap into the signal wire to count each burst. Kills two birds with one stone. Since the halo gun has no semi I would lock it into 3 round burst. If you want semi you would need a mechanical means of engaging the cut off lever. This should also close an electrical switch so you can distinguish burst and semi in your ammo display controller. You could probably get away with a circuit that watched the voltage drop when the motor engages to count shots, but I don't know how to make one of those. This could also prove unreliable when changing batteries.

For the ammo screen, I was thinking to have a proper 36 shot clip, and have the spring feeder like most gas pistols have, and attach a linear potentiometer hooked to that small pusher-plate. Have a connector on the mag and another inside the meg reservoir, going to a small microprocessor (arduino lillypad?). since it then knows how far the feed assist spring is compressed, some simple programming lets it know how many BB's are left! this way I can half-load it and not screw it up, as well as not needing to have a reset switch. Yes, I know that this probably means designing a custom mag, but that's kinda the point of the project; do as much custom work as possible to learn (not to mention making a wicked cool rifle)!

For the mechbox, this is where I have very little experience... can someone please explain the difference from a v2 to a v6? and the only thought I had was to use a PolarStar Fusion Engine, or some custom pneumatic circuit, for both increased reliability and better sound/response time (while still having semi-full auto, to my knowledge lore wise the gun has both). But please tell me if this is a bad idea or not, like I said I have little experience in this area

Lastly, lore wise the upper receiver seems to be a titanium alloy from what I can info I can find (cost may force a strong aluminum alloy, but we'll see ), while the bottom looks to be a plastic composite of some sort (glass fiber reinforced pollycarb?).

I intend for this to be a 1-2 year project, and over that timeframe can MAYBE afford to put up to 2 grand into it (SPREAD OUT!!!!! no one $1,500 part I have nothing else to say), so lets' talk in the idea of "if it's worth doing, it's worth overdoing"

[snafu]

Jun 3, 2012 19:36:33 GMT -5 Blitz said:

Buy a Polar Star fusion engine and strip the v2 shell off of it. Then you can make the body however you want and not worry about fitting a mechbox. You can even program 3 round burst and fps.

Ok this seems like the best idea yet.. Casper has a bit of experience with modifying the P* engine as he fit one in an m60, maybe he can chime in with some advise..

[Husky]

as far as the display screen this may be able to be modified or the technology used from this when it were to come out www.youtube.com/watch?v=6awM3HG43FE

[bobbunny]

Jun 3, 2012 19:36:33 GMT -5 Blitz said:

Buy a Polar Star fusion engine and strip the v2 shell off of it. Then you can make the body however you want and not worry about fitting a mechbox. You can even program 3 round burst and fps.

Smart man. This is a pretty good idea IMO for the build.

Body wise, I don't think there's much help here considering you want to roll with something accurate.

One problem I see though is maybe the bullpup design, but that's probably because I have no idea how the airsoft versions really work, unless it's the same as the real steel versions. Still, what do you plan to do with the mag well?

[specks159]

forums.airsoftmechanics.com/ would probably be a good place to look with regards to the electronics on this. There are a few people over there who do electronics and programming with their AEG's and would probably be interested in some of this stuff.

[X]

Jun 3, 2012 19:55:40 GMT -5 LoneWolf said:

Jun 3, 2012 18:19:59 GMT -5 X said:

I would use an off the shelf 3 round burst MOSFET. Tap into the signal wire to count each burst. Kills two birds with one stone. Since the halo gun has no semi I would lock it into 3 round burst. If you want semi you would need a mechanical means of engaging the cut off lever. This should also close an electrical switch so you can distinguish burst and semi in your ammo display controller. You could probably get away with a circuit that watched the voltage drop when the motor engages to count shots, but I don't know how to make one of those. This could also prove unreliable when changing batteries.

For the ammo screen, I was thinking to have a proper 36 shot clip, and have the spring feeder like most gas pistols have, and attach a linear potentiometer hooked to that small pusher-plate. Have a connector on the mag and another inside the meg reservoir, going to a small microprocessor (arduino lillypad?). since it then knows how far the feed assist spring is compressed, some simple programming lets it know how many BB's are left! this way I can half-load it and not screw it up, as well as not needing to have a reset switch. Yes, I know that this probably means designing a custom mag, but that's kinda the point of the project; do as much custom work as possible to learn (not to mention making a wicked cool rifle)!

For the mechbox, this is where I have very little experience... can someone please explain the difference from a v2 to a v6? and the only thought I had was to use a PolarStar Fusion Engine, or some custom pneumatic circuit, for both increased reliability and better sound/response time (while still having semi-full auto, to my knowledge lore wise the gun has both). But please tell me if this is a bad idea or not, like I said I have little experience in this area

Lastly, lore wise the upper receiver seems to be a titanium alloy from what I can info I can find (cost may force a strong aluminum alloy, but we'll see ), while the bottom looks to be a plastic composite of some sort (glass fiber reinforced pollycarb?).

I intend for this to be a 1-2 year project, and over that timeframe can MAYBE afford to put up to 2 grand into it (SPREAD OUT!!!!! no one $1,500 part I have nothing else to say), so lets' talk in the idea of "if it's worth doing, it's worth overdoing"

These guys are totally right P* is the way to go if it fit's into the budget. They are new enough that I didn't even think about it. der...

I don't know about that potentiometer idea. The mag would have to be single stack for sure. Most AR mags the tube in the mag is wider than a bb. This would give you inconsistent readings. With a properly sized tube it would be more do-able. Even then though I'm not sure as to what sort of accuracy you could get. I'm not an electronics guy really (more into software) so take what I say with a grain of salt. It sounds like a cool idea though. The other thing is when the resistance is on a border line your ammo count would flip back and forth. This could be dampened with some hysteresis but then you might lose accuracy. Maybe instead you would wait for a new mag to be inserted and do a best guess based on a look up table. From there you would wait for a drop in resistance by X amount for a round to go through. Or the ammo could still be hooked up to semi/burst/auto switch and it could use that to count down rounds.

If it didn't work I would have a reset switch that get's closed when the mag is inserted. Then you just have to look for a open/close event to reset the ammo count, no manual button press. Not sure if the "real" thing is suppose to have a bolt release, that could be used also.

I read the books, but I can't remember squat.