Gun design questions

T

twoblink

New member
While I'm not John Moss Browning by any stretch of the imagination, I am however trying to (in my spare time, whenever that is) design a rifle. I see the popularity of the AR15's, and I don't think they are very well designed, dependency on too many small parts, it sh*ts where it eats as they say in the military, it's main spring is dependent on the existance of a buttstock being intact, the sights are too far apart from the barrel so your parallax is great, there's no positive charge on the handle, thus the need for the stupid postive lockup button, you cannot rerack without moving your face, etc... I can go on.

So I'm trying to design a gun with a few of these goals:

~5.5lbs
~.223 based
~grip type (pistol, or rifle grip) can be changed and reconfigured
~based on the AR15 magazine (so hi caps are possible)
~highly modular
~sights and barrel are very close
~easy to change barrel
~easy takedown
~fewer than 50 parts total
~no single part is smaller than 1" in size (So it's easy to find, hard to lose)
~single spring for recoil absorption as well as next round cycling.
~strong lockup
~self-contained trigger group
~generic cross bar safety (I find these to be the easiest to engineer and the most difficult to screw up)
~charge handle is both positive and negative.

That's just some of the goals.

Hmm.. My design thus far is pretty radical. The lockup is the part I have been working on for a while, I am designing it based on a few new concepts. Are you all familiar with air compressors? You know how the attachments work? Ball joints, you lift the spring based cover on one end, slide the ball in, and the spring cover drops. The lockup on that is pretty solid, and the stress is distributed evenly because it's round. That means the entire bolt would actually be a small ball only.

The other part that is semi-radical, is the firing pin. Instead of a hammer based firing mechanism, I was thinking of moving towards a partial tention spring striker, kind of like a Glock internals. This further reduces the space required, as the spring is at partial tention, and a pull of the trigger adds more tention, then slides off the spring lip, giving you a striker fire. Because the trigger mechanism is below not behind (because there's no need for a hammer to sit behind the firing pin) I figure this combination should reduce up to 3" or so, on the rear end space need for the rifle. The cycle length would only need to be basically the length of the bullet. Also, the lockup is inside the barrel (as the spring loaded ball shroud covers both the barrel lip and the bolt completely). All this should combine for a very short cycle, and short length needed.

But I'm looking for any other radical lines of thinking that you all have had, which I have not thought of. Any suggestions are welcome.

I do not know if this format will allow for gas cycling reliably, if not, then it will be redesigned into a bolt action.

Hope my description above made sense.

Thanks.
Albert
 
never get it produced, not enough demand,

AR's work just fine, and there's millions of both them and other auto rifles already extent. So there's little demand for a new one. Mental exercise is better done on stuff that's more needed.
 
All of the easily available 5.56mm semi-auto carbines have signifigant design failings. Anyone who comes up with a better design deserves an ear (...if people didn't strive for perfect, there'd never be any good!)

The idea of using a striker mechanisim in a rifle is interesting. Just make it out of metal, please! No sqooushy Glock triggers!

I don't know if a ball-type lock could be made strong enough to handle the level of pressure a rifle cartridge would produce. At work, we use a lot of pneumatic sanders, die grinders, impact wrenches, etc. All of them run off a big Ingersol-Rand air compressor that keeps everything on a constant 90 psi, which I understand is pretty high. A 5.56mm cartridge produces around 45,000 psi. An old-fashioned rotary bolt/captive piston might be the way to go, although the idea of hydraulic-delay blowback is interesting...

Make everything ambidextrous. Put the bolt latch directly forward of the trigger guard, so's you can lock the bolt back one-handed. Ditch the crossbolt safety, it ties up the finger that you use for pulling the trigger.

I'd really like to see a rifle that ejects down and forward, instead of to the side.

You said something about easy takedown? I'd kill kittens for a .223 carbine that breaks apart like a Wild West Co-Pilot. Talk about an awesome travel gun. Not sure how you could engineer that, maybe an interupted thread at the forcing cone...

- Chris
 
I've never seen the bolt on a G3, but I heard that it locks similarly to the slide on my CZ-52. It uses a pair of rollers. This part has already been invented and it seems quite simple and quite robust ... if the rollers and their engagement surfaces are heat treated properly.

What ever anyone ever tells you, remember this: mental exercise is NEVER wasted ... it just keeps you sharp. ;)

Saands
 
Shucks, sure it will never get made. I'll be sure to tell that to Robinson Armament about their M96, or Armalite and their AR-180B, Or any of the makers of .223 AKs, or Williams Arms who is prototyping a aluminum receivered .223 FAL, or Bushmaster about their Bullpup that they bought off of Edenpile. Or any of the other .223 semi auto weapons that do the same thing as the AR. And that is of course only counting civillian legal guns in the states, not all of the different manufacturers around the world who are always looking for something better to sell. They should know that nobody would ever tool up to build something that would compete against the great and omnipresent mega rifle; the AR15.

The perfect weapon system has not been designed yet. Doesn't hurt to keep looking. Good luck to you Twoblink.
 
Well, I happen to be an AR fan but nothing is perfect so have at it.

Some of my initial observations;
DPMS had a quick change barrel prototype at the SHOT show a few years back that would give you a good quick takedown feature.
From what I have seen, the cross bolt safety and ambidextrous operation are almost mutually exclusive. The pivoting type (AR/HK) is more natural to me.
If the sights are close in line with the bore the design will have more muzzlerise than the AR. Not a big deal since you don't mention full auto but that was a design criteria for the AR so it is not a design flaw exactly.
A self contained trigger group might well be harder to clean and service (trigger job?) than the AR type. Not real sure, may not need a trigger job (hopefuly) but my old HK's trigger was a pain to clean compared to my AR.
Positive and negative charging handle would indicate a recriprocating bolt handle, not exactly friendly to an ambidextrous design. It will also provide an opening for crap to enter the action OR the need for extra parts to close that opening.

Best of luck.
 
I don't know if a striker style trigger group is really that good of an idea with a rifle either. If you think about it, the rifle is operating in a single action mode with the bolt recocking the hammer upon operation. A striker assist wouldn't really help anything that much.
 
Hmm, one of the things I have been thinking about, if not a ball joint lockup, is a double fishhook lockup. The harder you push, the tighter it locks.

I am left handed, so TRUST ME, anything that is designed will be left hand friendly.

I own a Audi A4 Quattro (Love it!) and their Quattro worm gear theories are great. On the worm gears in the quattro system, the torque is distributed to the wheel with the most grip, that is done by a series of transfer worm gears, which basically says the tighter it bites, the more torque it gets, because the ones that don't bite tight act like a slip clutch. I'm going to dig up my quattro white paper again and reread it.

The part about the spring striker is, there does not need to be space allocated to the rear of the striker, like you would a hammer based trigger system. There can be a frontal tab lobe, which is what the trigger pushes. This reduces the space needed in the rear of the receiver by about an inch at least. Also, the bolt can be shortened significantly. (total bolt size need not exceed 1.5", that's ball joint, extractor, and striker spring housing.)

I'm set on 50 parts or less. I know the pneumatic air accessories are only at 90psi, and actually at my dad's place, I've used some that are 230psi, and I know that is a far stretch from the SAAMI pressures of a .223, but most of those are lipped systems, not a full ball joint. Given a 1" full ball joint that has nothing in the middle but a spring tentioned striker fire system with a lobed tab at the bottom, and a ball shroud that is attached to the barrel, and the bolt ball slides in, the lockup is stronger the more pressure you put on it. 45,000psi strong? I don't know, but we'll see..

The ball joint cycles really easily, since it's circular, it does not ride on rails per say, but it is itself it's on roller! So lube is never a problem, and a jam from overheating or "gunk" is almost impossible. The lockup allows for easy control of gas flow, since it is circular, so it's even distribution of pressure. No leaks rearward ever.


Hmm. What I envision for takedown. 2 screws for the stock to be taken down (or better yet, two pins) and the trigger assembly comes out completely with 2 pins, the barrel is a torque twist star (allen wrench like) twist system, no screws needed. The receiver comes off when the trigger assembly comes off, there's the ball joint which is also your bolt, and the housing. That's it. The gas system, is just a tube with a top like the M1A.

Here's the other "innovation" I've been thinking about. Scope mounting.

My rifle will have a ZIF (Zero Insertion Force) scope mount system. For those of you who are familiar with CPU's, just like that. For those of you who aren't familiar with ZIF's as a concept, it looks like quick releases on bikes. 4 holes, evenly spaced, with ZIF levers, so you drop your scope mount in, and flap 4 flaps and you have a rock solid lockup, that is out of the way as the flaps will lay completely flat.

Take down should take me no more than 5 seconds, it should disassemble into 4 major parts:

1) trigger group
2) stock
3) ball joint bolt
4) Receiver + barrel + gas system

a torque wrench that can be put into the butt stock to twist remove the barrel, and the gas assembly.

The buttstock should be able to be removed without touching the other components, that way, you can remove that portion for easy storage and travel. The buttstock and the rest of the gun should be able to fit into a standard briefcase, sitting side by side.

Maybe tonight, I'll do a parts count on the portions I have in mind so far. I think I might be a little bit over 50, I'm not sure. I know I know, people say, why put such rediculous constraints on yourself, but then again, I say, look at the M1 Carbine, so few parts, reliability is war tested. I'd prefer it over the AR15 because I don't have to look for tiny little springs.

I would have loved to sneak in a loaded chamber indicator, but I probably won't be able to.. also, I don't want people to come to rely on that as their way of checking whether a gun is loaded. Also, parts count is an important criteria to me.

I'm going to try to tackle "gas operation" sometime this week, most basic gas systems are not to my satisfactory.

Christopher II, of course the striker system will be made out of metal! I can't stand the spongy trigger of the glock either! That's why I bought a steyr M40 :-)

hydrolic-delay as a cycling system, from what I can dig up, has not been done before in a gun. I would love to design a short (very short) stroke system, to cycle the gun, without exposing the gas tube to the world. Something small enough to fit into it's own housing, with very few parts. I'm actually thinking about a dual staged system for this. Very interesting thought.. Like a locomotive steam system, it pushes one direction, and then the other, because the gas chamber opening is altered. That way, I get BOTH a positive ejection, and a negative direction force feed of the next round, all from gas. If that's the case, then the spring does not have to be that strong, and I can all but guarantee that there will be no more than 1 main spring used. I haven't figured out how that will work, so I'm digging for locomotive blueprints.

Christopher II, the other system I was thinking about was for the stock attachment. What about a slide in fit?? There's a rail based guide, 2 tabs that stick out, and the buttstock slides in until you hear "click" and it's got a solid lock. That way, the receiver rear face is the ajoining face to the buttstock! You can then add a pistol grip or anything else you'd like, since there's a common interface. You want to removed it, push a side rod out, rotate it 45 degrees, and the two tabs sticking out, will flip down. Slide out your buttstock. I'll have to think about that one for a moment.

But yes, mental exercise is best done on stuff that is needed, and a .223 rifle with the qualities I've mentioned before, IS something that is needed..

Albert
 
Jake,

You are assuming that the recoil on my gun is the same as that of an AR15. The the report is somewhat milder, then the sight so close to the barrel will not present that big of a problem, also, if the blowback recoil is very straight, then that will take a little bit off the edge on the second shot accuracy.

If the self-contained trigger group is in a housing assembly that is easy to take apart and reassemble, then it's no problem as far as cleaning. But I hear what you are saying, I'll definitely keep that in mind. Ease of cleaning is a definite criteria for me.

Shuck, Aiwa stereos will play music, go ahead and tell all the audiophiles not to design anything new. It's the same thing, just because it's en-mass doesn't mean it's done correctly. And as a engineer and programmer, it doesn't work UNLESS it's right, (the NetBSD motto) is what I abide by.
 
Ambidextrous.

Charging handle on left side(for right handed shooters) so as to maintain weapon at shoulder.

quick-change barrel, a la the AUG

if you want to reduce sight height, put the gas mechanism underneath. I personally like it where it is just fine.

two-stage trigger, I think Stoner designed it.

caseless if you can solve the problems everyone else has had--better thermal efficiency.

I don't have a problem with small parts. You shouldn't be field-stripping in combat, anyway. Squirt it with oil and keep shooting.

Bullpup style for tight quarters, weapon rest, etc.

don't waste time on a bayonet.

I've often wondered about the ability to insert a second mag before the first runs dry...feed from either side, maybe? It alternates until one is empty, then you replace that one. This may be undoable.

Sling swivels mounted for multiple sling options.

It might not sell, but it never hurts to speculate.
 
I have not done my trigger homework (as of yet) so I have not decided on the trigger, but I really like my M1A trigger a lot, easy slack, tention, crisp 3lb break. So probably the same two-stage feel.

alternating magazine feeds?? Hmm. I'll think about that one, but that might not be possible.

I do have problems with small parts, they generally are harder to find and refit. Also, very small springs are probably quicker to fatigue than big main springs.

I would like to make the gas system small enough to hind inside the lower forearm of the stock, that way, it's protected.

I've looked at about 100 nipple/coupler combinations for pneumatic tools. The highest pressure ones I've seen was 6000psi, that is not acceptable. I have not seen a ball-joint/coupler combination though. So I don't know what kind of pressures that combination will be handle, since it's not just biting on the lip of a nipple like most pneumatic tools, but swallows the entire balljoint into the lockup system... Oh well, more research.

I'm trying to solve the thermal efficiency problem by having the least amount of parts, and having the most minimalistic friction points.

Thanks for the suggestions thus far.
Albert
 
Your ball locking system sounds very much like the HK roller locking system. It's not simple in any way. 9mm versions have several different locking pieces for depending on type of ammo and whether a suppressor is used.

What I'd like is a quick and easy conversion of ARs to a gas piston setup. You could use the gas key securing points to attach the piston to the bolt. A new front sight assembly would be required that is now more of a FAL or AK style gas block. All of this would hopefully, fit under the current M4 style handguards.
 
Madmike, you won't be field striping the beast during a firefight but in the field I have had to help search the ground for lost firingpin retaining pins and other small parts. People should be responsible for keeping up with their parts but it is an imperfect world. The M60 was notorious for losing small parts but that is another topic. Don't get me started on that piece of crap.
 
Madmike, I have to agree with Jake. When I was at combat camp, during the rifle series, we all had a bunch of different rifles. Mostly FN/FAL's, and AR15's. After about 2000 rounds, every rifle started having some gunk buildup and thus some reliability issues. We took a water break, in which a few of us, did break open the guns, and tried to scrape some gun out, or lub a few places. a very quick field strip of my M1A was not bad, the trigger group stayed intacted, and the barrel and stock was very hard to lose...

I might tend to agree with "squirt some oil on it and keep shooting" but sometimes, you have to break the guns down to a certain point before you can squirt some oil. If I can possibly accomplish my (no item is smaller than 1") goal (at least with regards to a general field strip) then I'll be very happy.

Destructo,. can you give me any help on reading up on the HK roller locking system?

Thanks.
Albert
 
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