Real Steel Halo MA5C Rifle

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Loess

Member
For the last year or so, I've been working on combining my job as a CAD worker, my engineering degree, and some gunsmithing experience to do something very awesome.

I'm going to build a real-steel, live firing MA5C.

I have been staying at the office after hours, and spending lunch breaks at my desk, and I finally have some models far enough along that it's time to share some screen shots with the folks here.

About a year ago, I was reading about old, unusual rifles, and ran across a video of the internal components of the German FG42 Paratrooper rifle. Seeing how short the action in it is, I started thinking about using it to make a functional MA5. After somewhere north of 500 hours of design time, I've gone away from the FG42 operating system, to my own custom derivation of a Leader Dynamics T2 rifle.

I've given up on fitting the 7.62x51 NATO cartridge into the rifle that the fiction specifies, since it's just too big to work. (That's where most of the 500 hours went.)
Instead, I'll be chambering it for 5.56x45, since I already have rifles and the reloading equipment for it.



I'm currently looking at building a custom reciever around a stock AR15 barrel and barrel extension, with a custom bolt carrier and a modified AR15 bolt.


Here's a view of the gas piston, if you watched the Leader video, you should recognize how it works.



The piston and charging handle go through the trunnion block, and push on the bolt carrier. The piston will push the carrier for 0.75 inches, which puts enough energy into it to completely cycle the rifle. The charging handle also goes through the trunnion, but it will run back through the entire travel length of the bolt.


The bolt and carrier lock in place much the same way that a standard AR bolt does.


These screen shots also show the extended feed ramp.
Since the rifle is so short behind the magazine well, I had to figure out a way for the bolt carrier to pick up a round from the mag, and pull it forward into the feed ramp, then on the next cycle, the bolt will pick up and load the round in the feed ramp as it is grabbing the next round out of the magazine.

This will do for getting ammo into the chamber, but it's going to be more susceptible to feed stoppages.


This design has the advantages of using off-the shelf parts for the barrel extension and bolt, since they have to be cut from tool steel and hardened fairly precisely. It also will use standard GI magazines, to remove some complexity there. I'm still kicking around the idea of machining the locking lugs and barrel mounting threads directly into the trunnion, since that would eliminate any chance of the barrel extension working itself loose from the trunnion.

I don't know exactly how soon I'll be cutting metal, since I want to have the models fully complete and detailed, and the drawings made before I begin ordering parts.


I suppose I should add that Yes, this is legal where I live. It will be semi-auto only, to stay that way.
 

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Riceball

Master Member
Very interesting project, I look forward to seeing your progress on this. If the rifle works you should consider getting an FFL so you can do a run of them, heaven knows that there's not a whole lot of new guns coming out that aren't a variant of the AR.

If you can't get it to work as an entire gun or if it's proving to be more difficult than anticipated you might want to consider making it as a shell to the Ruger 10/22 or Mini 14, both are very adaptable to to new shells/bodies and I think that both can be converted to bullpups as well. The nice thing about making a shell is that you wouldn't need an FFL to sell it and I'm sure that there are enough 10/22 or Mini-14 owners who are also Halo fans that they would sell fairly well.

Sent from my KFTT using Tapatalk 2
 

Loess

Member
awesome, legal?

Yep, semi-auto only, and well above the minimum barrel length.

In the USA, federal law (and state law where I live) is that you can build firearms for your own use. You still need to comply with the various laws about what types of firearms are legal to own, the 1934 NFA requires a $200 tax and registration for things like short-barreled rifles or shotguns, and the manufacture of new full-auto firearms was prohibited for non law-enforcement or military use in 1986.

Study up before you build something like this, there are frighteningly easy ways to get yourself 10 years in federal prison.

Very interesting project, I look forward to seeing your progress on this. If the rifle works you should consider getting an FFL so you can do a run of them, heaven knows that there's not a whole lot of new guns coming out that aren't a variant of the AR.

If you can't get it to work as an entire gun or if it's proving to be more difficult than anticipated you might want to consider making it as a shell to the Ruger 10/22 or Mini 14, both are very adaptable to to new shells/bodies and I think that both can be converted to bullpups as well. The nice thing about making a shell is that you wouldn't need an FFL to sell it and I'm sure that there are enough 10/22 or Mini-14 owners who are also Halo fans that they would sell fairly well.

Sent from my KFTT using Tapatalk 2

I've kicked around the idea of building a shell, but I'd really love to scratch build most of the non-critical parts.

I did see a guy a while back who used an AR15 lower to make a really nice looking bullpup.

I've actually started looking into what it'd take to get an FFL and set up for doing some gunsmithing and custom rifle building. Engineering texts are way easier to understand than zoning regulations and business laws.
 
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Loess

Member
Ok, so now that I have internet back, I can post what I've worked on since last Thursday.

Worked a bit on the gas piston and gas block, this is a direct impingement style piston.


I'll probably have to build a barreled action as a test stand prototype for tuning the gas system and recoil springs.

****
And here, I go and change the rifle to another caliber entirely,
I've been kicking around between 5.56x45 and 5.7x28. I've liked 5.56, because it is (relatively) available, and (relatively) inexpensive, and could be run with standard AR magazines. It's also usually available in bulk quantities.

5.7x28 is appealing, because the cartridge overall length is fairly short, so it fits the length of the rifle much better, the case has straight walls, so it's easy to design a custom magazine, and the case is smaller diameter, so it has less bolt-thrust when it's fired. It's less common, and usually more expensive, though.



Changing caliber also lets me move the hammer back where it's supposed to be.


Which lets me move the bolt cam pin back to the side of the bolt carrier, where the Leader had it, and it doesn't mess with the guide rods.


I also spent some time cleaning up the bolt carrier, guide rod, and recoil spring assembly. A lot of this is looking ready to start cutting.


Now, I need to start looking for short-run metal stamping vendors, to make the sheet metal sides, and the magazines.
 

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Loess

Member
Been busy at work, so there hasn't been much time to work on this, and I've been fighting with laying out the fire control group, to try to prevent the usual problems bullpups experience with terrible feeling triggers.


I did get a chance to add the stamped designs on the sides of the sheet metal, though.
 

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Riceball

Master Member
Looking good, keep up the good work, can't wait to see the finished gun. Btw, I ran back what I said about getting an FFL to sell copies, that would require an 07FFL and as cool as this is, I don't think that you could sell enough to justify the couple of grand in annual ITAR fees that come with an 07FFL for manufacturing. Now if you could team up with an existing FFL that would be great.

Sent from my KFTT using Tapatalk 2
 

Loess

Member
Looking good, keep up the good work, can't wait to see the finished gun. Btw, I ran back what I said about getting an FFL to sell copies, that would require an 07FFL and as cool as this is, I don't think that you could sell enough to justify the couple of grand in annual ITAR fees that come with an 07FFL for manufacturing. Now if you could team up with an existing FFL that would be great.

Sent from my KFTT using Tapatalk 2

Thanks!
Yeah, I looked into that, too, and I don't think that I'd make back the FFL and ITAR registration fees before Microsoft and 343 sent the lawyer squad after me...

Depending on interest, I could do parts kits, and let people make their own receiver, and do final assembly. There's plenty of precedent for that with 80% AR15 lower receivers. That'll take some research, and talking to the BATFE for a determination of how much work would have to be left undone.
 

Xplicitt

New Member
This looks amazing! Are there any plans to integrate an optic or Iron-sight? Any other electronics? Ammunition count, Camera for an Integral Optic?
 

Riceball

Master Member
This looks amazing! Are there any plans to integrate an optic or Iron-sight? Any other electronics? Ammunition count, Camera for an Integral Optic?

An optic or even back up irons would be easy enough, all he has to do is add a pitcatinny rail
to it although it would no longer be accurate. Adding integral electronics would probably be extremely difficult if not impossible.


Sent from my KFTT using Tapatalk 2
 

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Loess

Member
Oh, this has to have the electronics!
I really want to put the compass and a working counter into it.
I need to teach myself a lot more about electronics than just how to connect some LEDs and a fan to a battery pack without burning them up, though.

According to Halopedia, it does have back-up iron sights, even though they don't show up in any of the renders.

I've been working on the smaller details since the last update, like the fire-control group, which is going to be an AR15 hammer, trigger sear, and disconnector.


I've also worked on the handguard, lower receiver, and buttplate.


I've started breaking this up into the assorted subassemblies and weldments that it'll be built up from, so that I can figure out how everything attaches together. There's also some thinking of what exactly some of these parts will be. Some parts are obviously sheet steel, and the upper shroud is probably going to be compression-molded fiberglass, but I haven't completely decided what to make the lower receiver out of. It may be fiberglass, or CNC'd plastic or aluminum. I'm leaning toward fiberglass over a sheet steel frame, since that would be fewer parts to contract out.
 

Loess

Member
Awessooommeee. This is the Halo 3 assault rifle?

Thanks!
Yeah, this is the H3 and H3:ODST version.

I spent lunch break today setting up and running some FEA simulations of the bolt and trunnion, The good news is that this shouldn't kill me.


The stress levels came in below the yield stress for hardened and tempered tool steel (104 ksi), so it shouldn't deform the locking lugs, which would lead to the rifle blowing up.

I separated the sides of the sheet metal handguard into 2 separate pieces again, because some quick calculations of the stamping forces for them were up at 90 tons for each side, and I wanted to make sure that they wern't going to be over capacity for the short-run stamping places I'd found.

After work, I spent a few hours working on the fire-control group, trigger linkage, and the internal structure to hold the various lower parts in place.


Going to take a lot of spot-welds to hold this together.

The stock and butplate attach to a pivot pin, and hinge down to allow field stripping it for service and cleaning.


Looks like a rifle!


It's about time to start getting quotes for some of these parts.
 

joberg

Master Member
Love the planning phase and with good reason; working with real gun is always tricky and seeing how you're doing the study and the engineering of the whole weapon is reassuring.
Subscribing for sure...way cool if you achieve life fire:)
 

Lear60man

Master Member
RPF PREMIUM MEMBER
I dont get Auto CAD type stuff but I do understand firearms and custom builds. Be safe and please keep going. As long as you observe federal laws.......blaze on!
 

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