Mixing Bullpup And Conventional Gun

[lemd]

Hi everyone,

Recently I have some ideas about weapon system, and I think I can/ should make money with them. I don't work in defense/ weapon industry, and I think for large system like tanks, aircraft,... the investment is huge, and the market is small and only available to home companies. Because of that, only small arm is the potential field, and so I pursue this idea: mixing bullpup and conventional gun.

I am looking for cooperation. Any advice, comment, feed back on the mechanism or how to commercialize the idea is welcome. Currently, I will post it on internet and try to contact every possible company (using world.guns.ru as the reference). If any one here works in small arm industry, or having friend work in that industry, or know someone that I should show this idea to, and if I can make a deal (hopefully), I will share profit. Now, about my idea.

1. Firearm that can be switched between bullpup and conventional configs quickly on the field.

Currently there are two main layouts of small arm: bullpup (BP) and conventional (CON), each has its own pros, cons and supporters. Some companies even pursue two parallel versions of a similar firearm, e.g. MSBS Radon of Poland, BMCR and CMCR of Singapore. My idea is building a single firearm that can be switched quickly between BP and CON configs on the field. There are many potential advantages:

a. Bring the end to bullpup vs conventional gun debate, because user can have both at once.

b. Simplifying the manufacturing process: instead of building two version, e.g. Radon MSBS, BMCR and CMCR, just build a single firearm and let the customers decide later which one they need.

c. Lowering the mass production price. I guess having two versions simultaneously, e.g. BMCR and CMCR, will poses a risk. You can not decide which one will be the requirement/ trend in future, so they need to be produced in a limited number. With a firearm that can be switched between CON and BP on the field, manufacturer has more freedom to build firearm at a larger quantity at the right time, e.g. when material cost is low. This will leads to lower price per firearm even the firearm is a litter more complex.

d. Higher profit margin. The firearm is essentially 2 in 1, which means benefits to user. The extra feature means manufacturer can charge additional price, even when the real manufacturing cost is lower. IMO for individual buyer, a firearm that can be switched between the two is very cool.

e. Simplifying logistic: can be a common firearm between different armies, or different forces. For example, some armies in NATO use bullpup while some NATO countries use CON firearm. It seems special forces prefer CON while normal forces prefer bullpup. A common firearm is a very good reason to start lobbying for a new project.

f. A firearm in different situations. For example, change to bullpup while firing inside vehicle, and change to CON gun when dismounted.

g. Allow user to be trained in different firearms. Gaining knowledge and skill (about different systems, or simulating enemy weapon...) are the most important thing in modern times.

h. Allow individual user to freely choose which one is best suited for himself. For example, in the same army, some may prefer bullpup while some may prefer CON guns.

The idea is based on the main different between BP and CON firearm, which is the positions/ the order between the trigger/grip and the feeding port (magazine well, belt tray). The goal is to change this quickly on the field. There are people that mod CON gun to BP, but there is no firearm that can be switched back and forth between the two. Please see the images below



FIG. 2 illustrates 4 methods to quickly switch between BP and CON.

FIG. 2a shows a firearm 201 with two feeding ports 211 and 213, and a trigger 212. The feeding port 211 is in front of trigger 212, while feeding port 213 is in the back of trigger 212. If user wants to use firearm 201 as a conventional gun, user will load magazine into front feeding port 211, and if user wants to use as a bullpup gun, user will load magazine into rear feeding port 213.

FIG. 2b shows a slightly different version of FIG. 2a. Instead of using two fixed feeding ports, the firearm 202 in FIG. 2b comprises a detachable feeding port 221, and the detachable feeding port 221 can be attached in the front or in the back of the trigger 222, depends on user.

FIG. 2c shows firearm 203 with two triggers 231 and 232 and one feeding port 233. The trigger 231 is in front of feeding port 233, while trigger 232 is in the back of feeding port 233. The gun 203 also comprises an extendable stock 234. When user wants to use the firearm 203 as a conventional gun, user uses trigger 232, and extends the stock 234 as shown in FIG. 2c. And when user wants a bullpup gun, user uses trigger 231, and collapses the stock 234.

FIG. 2d illustrates a slightly different version of FIG. 2c. Instead of using two triggers, firearm 204 comprises a detachable trigger 241 that can be attached in the front or in the back of the feeding port 242.




FIG. 3 shows more details about firearms with two feeding ports.

FIG. 3a, 3b, 3c show the firearm 310 with barrel 311, front feeding port 312, trigger 313, rear feeding port 314, cartridge pusher 315, support 316, cartridge lifter 317, bolt 319. FIG. 3b shows the gun 310 when used as bullpup firearm. Magazine 3111 is attached to rear feeding port 314. FIG. 3c illustrates the gun 310 when used as a conventional gun. Magazine 3111 is now attached to the front feeding port 312. The cartridge 3112 is pushed backward by cartridge pusher 315, through support 316, to cartridge lifter 317. The whole mechanism works similar to many rifles with tubular magazine, but it allows, for example, detachable box magazine to be used, which allows firearm to be reloaded quicker than tubular magazine.

FIG. 3d, 3e, 3f show another embodiment with two feeding ports. FIG. 3d shows the gun 320 with barrel 321, front feeding port 322, trigger 323, rear feeding port 324. FIG. 3e illustrates the gun 320 when used as a bullpup gun wherein magazine 325 is loaded into rear feeding port 324. Barrel 321 is fixed to the back of firearm, as shown in FIG. 3d and 3e. FIG. 3f illustrates when the gun 320 is used a conventional gun, wherein magazine 325 is loaded into front feeding port 322. Unlike the gun 310, there is no mechanism to push the cartridge backward, but the barrel 321 and firing mechanism 328 are moved forward to match the position of front feeding port 322. This can be done by detaching those components from old locations and then reattaching them to new locations. Another way is attaching all those components to the upper receiver, and then attaches the upper receiver to the lower receiver at different locations.



FIG. 7a and 7b illustrate the gun 710 with two triggers 711 and 712, a feeding port 713, extendable stock 714, pistol grips 715 and 716. Trigger 711 is in front of feeding port 713 while trigger 712 is in the back of feeding port 713. Magazine 717 is loaded into feeding port 713. The stock 714 is extended in FIG. 7a and collapsed in FIG. 7b. Both triggers are connected together by linkage 718, and is connected (not shown) to firing mechanism (sear, hammer….). FIG. 7a illustrates the gun used as conventional gun, with stock 714 extended, and pistol grip 716 and trigger 712 are used to handle and fire the gun 710. FIG. 7b illustrates the gun used as bullpup gun, the stock 714 is collapsed, while the trigger 711 and pistol grip 715 are used to control the gun 710.

FIG. 7c and 7d illustrate firearm 720. Similar to the gun 710. FIG. 7c illustrates the gun 720 used as a bullpup gun, with the trigger 722 and pistol grip 726 folded inside stock 724 while stock 724 is collapsed. In this configuration, the trigger 721 and grip 725 are used to handle the gun 720. FIG. 7d illustrates the gun 720 when used as a conventional gun. The stock 724 is extended, and trigger 721 and grip 725 are folded to clear the space, which may be used for other attachment, e.g. a grenade launcher. In this configuration, trigger 722 and grip 726 are used to control the firearm 720.

FIG. 7e and 7f illustrate firearm 730, similar to the firearm 710, but uses a detachable trigger instead of two triggers. Firearm 730 comprises feeding port 731, detachable trigger 732, extendable stock 733, detachable pistol grip 734, and feeding device 735. In FIG. 7e, firearm 700 is used as a conventional gun, with stock 733 extended, and trigger 732 is attached behind the feeding port 731. In FIG. 7f, firearm 700 is used as a bullpup gun, stock 733 is collapsed, trigger 732 and grip 734 are attached in front of feeding port 731. There is a linkage (not shown) that connects the trigger at both positions to the firing mechanism.



FIG. 12 illustrates firearm 1000, is switched from bullpup in FIG. 12a to conventional firearm in FIG. 12d. Pistol grip 1003 is detachable, and can be slide back and forth along a rail 1015. Firearm 1000 is a version of firearm 730 in FIG. 7e and 7f.

[lemd]

2. Firearm that has feeding port in the front (like conventional firearm) but barrel is extended to the back (like a bullpup)

This is a hybrid firearm, similar to firearm 310 of FIG. 3c above, but without the rear feeding port. This firearm will be compact as a bullpup, but has a external layout as a conventional firearm. Please see the images below:



FIG. 14 illustrates cartridge 1409 in magazine is pushed backward by a pusher 1407, before is pushed forward into chamber.

 

 

FIG. 15a suggests that cartridge 1515 may be pushed backward by pusher 1516 or pulled backward by puller 1517. It depends on design of the firearm and cartridge, e.g. rimmed or rimless.

 

FIG. 15b illustrates firearm 1520 with a fixed barrel 1521, feeding port 1522, trigger 1523, feeding device 1524, pusher 1526, support 1527, lifter 1529, bolt 1528. Firearm 1520 operates similar to firearm with tubular magazine and cartridge lifter. Pusher 1526 pushes cartridge 1525 to the back, through support 1527 to lifter 1529.

Support 1527 is a hollow cylinder, similar to a tubular magazine, and pusher 1526 operates as the spring of the tubular magazine. The user opens bolt 1528, and lifter 1529 lifts cartridge upward, before the bolt 1528 pushes cartridge into barrel 1521.

FIG. 16 illustrates a box magazine 1600. The tops of front wall 1601 and rear wall 1602 are below the top cartridge 1603, to allow cartridge 1603 to move backward easily.

FIG. 21a illustrates firearm 2110 with ammunition belt 2112. While there are machine gun that pulls cartridge to the back, e.g. PKM, this firearm has the barrel extended to the back like a bullpup gun.

FIG. 27 illustrates the perspective view of a simple blowback gun with pusher 2309, barrel 2322, bolt 2306, magazine 2307, support rail 2311, lifter 2312, rod 2314, spring and guiding rod 2318. FIG. 27b shows rod 2308 and pusher 2309 push cartridge 2310 through support rail 2311 into lifter 2312, while lifter 2312 is pushed down by slide 2323, and spring 2318 is compressed by the bolt 2306. FIG. 27c illustrates the bolt 2306 is pushed forward by spring 2318, and bolt 2306 is going to push cartridge 2310 into chamber of barrel 2322.

[lemd]

Well, those are my ideas. Any comment is welcome!

[Colin]

One thing the French have come up against in their search for replacement of the FAMAS is that to switch from bullpup to a "traditional setup" is that it would require redesigning weapon racks in vehicles, armories and elsewhere at significant costs. I suspect going the other way is slightly less of a problem. While your designs are interesting, for the average solider they will want to issue one rifle, with one manual of arms. It can be done such as how I carried a SMG and the rest of my gun crew carried FN's. The question is there a driving need to justify the expense and training required? A traditional gun and Bullpup that shares the same mag, ammo and as many of the controls in the same spot as possible might be doable.

[Chris Werb]

I'm really impressed by the effort you put into this, though I'm not sold on the concept.

[rmgill]

I can see SOME benefit for armory level configuration thats trivial. Doing it so it's doable in the filed seems complex.

Some troops would benefit from a bullpup, others may be better off with the manual of arms of a convetional rifle. Expecting troops to swap between the two is tricky and I think unrealistic.

Support troops get issued with rifles that are bullpups.
Primary combat arms troops like infantry, get the conventional weapons.

[DB]

If you have original ideas, you have to be very careful about making them public, or you may find it impossible to patent them. Take advice before posting too much detail.

[Simon Tan]

Fine effort but breaks KISS.

[Blunt Eversmoke]

Fine effort but breaks KISS.

Hm? The "conventionally-placed-mag" bullpup seems comparable to the PKM in terms of KISS, IMHO, and combines best of both worlds (well, no UGLs to balance that one out, but they suck anyway, right?). All it does is have a puller pull cartridge from mag and onto articulated feed tray. On a short-stroke gas-piston, it would be indeed complex to implement, but on any weapon that has any part travel any significant distance, it wouldn't be much of a hassle. Say, AKM bolt carrier travels all of 12.5 cm, with a puller on that and a second one on the bolt proper, it's what, 18 cm? Enough to be worthwhile. And what is the minimum travel for Ultimax bolt carrier?

[BansheeOne]

I really like the "conventional bullpup" idea too, kind of a reversed F2000 which pushes the spent brass out of the front to get around the ambidextrous ejection issue (something not addressed by this design BTW); but I'm also concerned about the added complexity, particularly stoppages related to what would appear to be a rather inaccessible feed tube. Suppose a cartridge somehow jams in there - what would be the procedure for clearing it relating to the other functions of the action? If the action itself jams, will unfired ammo pile up in the tube?

[Simon Tan]

OPERATING SEQUENCE (GAS OPERATED PISTON)

 

Cartridge Initiation

Propellant gas initiates piston operation (long or short makes no difference.)

Lower Carrier picks up cartridge from magazine. I am assuming an extractor catches onto the rim.

Upper Carrier is initiated by the Lower Carrier and begins rearward motion, allowing the bolt to unlock (prolly rotary), extract and eject the spent cartridge.

Lower Carrier is stopped against receiver buffer. Upper Carrier continues operating stroke further to the rear.

Upper Carrier completes recoil stroke and moves back under mainspring pressure.

Twin elevators lift the fresh cartridge into the feedpath and is stripped by the bolt of the Upper Carrier.

Upper Carrier and Lower Carrier move back into battery.....bolt rotates and closes.

Lower carrier extractor engages rim of next round.

 

REPEAT.

 

That is a complex multi- part carrier assembly with at least 2 operating springs, 2 extractors, cartridge elevators etc. Then you have to design a trigger group that doesn't interfere with the various recoiling elements.

 

A very complex operating cycle. Gas operated short recoil......

 

Can be done.

[Simon Tan]

You cannot have feed tubes with center fire spritzer ammunition. Unless you have spiral grooving a la Lebel which is even messier. PKM is top fed.

Edited May 1, 2015 by Simon Tan

[Blunt Eversmoke]

What I had in mind is not a tube with multiple rounds in it but a bolt carrier downward extension to strip cartridges from mag. Therefore, only one return spring. Extension strips cartridge from mag and brings it to a spring-supported loading paw, which sits where otherwise the mag lips would be. That only wins us as much lenght as the bolt carrier would travel (on the Ultimax, this would probably be enough - what is minimum bolt cartier travel there?, on the AKM with its 12.5 cm of bolt carrier travel, rather so-so). If one wants to win yet more length, a two-stage cartridge pulling arrangement would be needed, though, and you would have to cycle twice when loading a completely empty firearm.

[Simon Tan]

You need a 2 part carrier. That can be designed....it's the fire control that will be a PITA.

[Blunt Eversmoke]

You need a 2 part carrier. That can be designed....it's the fire control that will be a PITA.

As with any 'pup, innit

Re two-part carrier... Now here's what one could do with the AK-107 balanced action besides balancing the action

[lemd]

Well, thanks for comment and suggestion

 

It is patent pending (quite cheap because I do it all by myself), and I show basic because I don't want to reveal more details to let other capture the weakness (if any) of my design (and claim). But your suggestion is welcome if you don't want to patent it, because since you reveal it to public, it will stop other patent it. I already try to claim key features, and your suggestion will not have priority date over mine.

 

First, the complexity. could anyone can give more details? Here is my thought

 

The firearm 1 (which can switch between configs):

 

Extendable stock: simple, already done on issued rifle, e.g. G36

 

The two mag well or detachable mag well. Since firearm is mostly built around mag well, it is a bit complex since it require precision machining, but it is doable.

 

The two trigger or detachable trigger, IMO, is very simple. You only need a linkage with two holes, one in front and one in the back, so you can attach the trigger to it. Low precision required. There are people that mod CON to BP firearm, e.g. bullpup m14, bullpup aK 47, easily. The only improvement I made over them is making those process easier and repeatable.

 

For ejection, I didn't mentioned because I think it already on market, e.g. forward ejection... which is normal for bullpup. For a quick build, just normal ejection, because many bullpup still has them.

 

Complexity in conventional bullpup, modified PKM is the first thought. Just separate the puller (mechanism that pulls cartridge backward) and the bolt group.

 

What else do you think it makes the gun more complex?

 

Jamming in conventional bullpup

 

For belt feed, a modified PKM will have a similar jam rate as the PKM.

 

Jamming in tube may be an issue, and the fastest fix is let those component accessible easily, e.g. tube is made from two parts which can be opened to eject jammed cartridge.

 

Another approach should be modified belt feed for mag fed, e.g. catch the rim rather than push the cartridge as Blunt Eversmoke mentioned, so it can have similar jam rate to belt feed

 

You cannot have feed tubes with center fire spritzer ammunition. Unless you have spiral grooving a la Lebel which is even messier. PKM is top fed.

 

I already think about this. The pusher is a hollow cylinder, which pushes cartridge on the shoulder or the sloped side of the bullet. But I think about bolt action first, easy and manual, so the reload motion will be slow which may not damage the tip.

 

That is a complex multi- part carrier assembly with at least 2 operating springs, 2 extractors, cartridge elevators etc. Then you have to design a trigger group that doesn't interfere with the various recoiling elements.

 

A very complex operating cycle. Gas operated short recoil......

 

Can be done.

 

To avoid 2 springs, and to add additional travel, I uses this mechanism (image below). There is a gap between bolt group and puller/pusher. The operational spring and pistol apply to the pusher/ puller rather that the bolt carrier. The puller will travel as much as you want. The bolt carrier can travel as little as you want. And the difference between them is the length of the gap. This will be the quick fix that will be applied to PKM to separate the puller and bolt carrier.

 

2 extractors, I think it will be as complex as PKM. So not a big problem

 

Trigger group that doesnt interfere. The trigger is just a trigger, link it to the back (like bullpup). On 2D it seems complex, but in 3D it is easy to avoid interference. There is room for that, e.g. side by side, or rotate it a little, or upside down but after all, it depends on the specific design

 

Edited May 2, 2015 by lemd

[lemd]

One thing the French have come up against in their search for replacement of the FAMAS is that to switch from bullpup to a "traditional setup" is that it would require redesigning weapon racks in vehicles, armories and elsewhere at significant costs. I suspect going the other way is slightly less of a problem. While your designs are interesting, for the average solider they will want to issue one rifle, with one manual of arms. It can be done such as how I carried a SMG and the rest of my gun crew carried FN's. The question is there a driving need to justify the expense and training required? A traditional gun and Bullpup that shares the same mag, ammo and as many of the controls in the same spot as possible might be doable.

 

For average soldier, maybe. But I also want to aim at civil arm market. So I think for the one who purchases his own rifle, this design is cool, isn't it? You can have 2 at the same time, and try to play with it as you want

Edited May 2, 2015 by lemd

[Colin]

Hmmm, bullpup stocks are prohibited in Canada, make sure you know the laws of your target market. Make sure you use commonly available mags and trigger group if you can.

Edited May 2, 2015 by Colin

[Simon Tan]

I don't think you're really interested in what I think. It's very nicely drawn up. Now you need to go and get it printed out and tested.

[Colin]

yes 3D printing is a wonderful thing for prototyping, my friend did all his magazine designing that way. You can start with the softer cheaper materials and then as the design progress get the tougher more expensive plastics.

[Archie Pellagio]

This all comes down to the old chestnut: why?

 

The different ergonomics means you're effectively halving the training time for a soldier's primary weapon and to what end?

 

It isn't as though the secco is going to be giving his orders and go "we're going to be patrolling in bullpup mode today".

You've clearly put a lot of work and thought into it and if it works could achieve some success catering to the civilian market but this just strikes me as another Internet gun nut "wouldn't it be cool if" or "we can solve this super-specific problem if" solution that isn't practicable or worth the cost in the real world.

[Colin]

Yes but we fought a World war and Korea and Northern Ireland and whole host of other battles with Main Battle Rifles and SMG's issued, to very different arms with even different ammo, but they were able to get through it. Even I trained on those 2 myself, it's not hard with competent instructors.

[BansheeOne]

That's why I like the "conventional bullpup" design though - you get the advantages of both in a single package without having to fiddle around swapping parts and added training. Of course you possibly also get the disadvantages of both.

[Blunt Eversmoke]

That's why I like the "conventional bullpup" design though - you get the advantages of both in a single package without having to fiddle around swapping parts and added training. Of course you possibly also get the disadvantages of both.

Yes, having to design a way for ambidextrous use and a crisp, consistent, not-too-heavy trigger (although at least the Israelis showed it ain't that hard).

[Simon Tan]

No...a fella from PA.