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Ambidextrious Bullpup

Discussion in 'Rifle Country' started by Nightcrawler, Dec 29, 2003.

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  1. Nightcrawler

    Nightcrawler Member

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    Say I had a few million bucks to invest in the development of a rifle.

    I want an ambidextrious .308 caliber bullpup semiauto. By "ambidextrious" I don't mean a reversable bolt like the AUG or FAMAS, I want it to eject downward or in some direction that won't hit you in the face, regardless of which shoulder you fire from. (This would solve one of the big beefs many have with bullpups).

    I want it to be balanced so all the weight isn't in the stock.

    I want it to be sturdy and reliable; able to withstand frozen wind or steamy jungles, and I want it to be tough enough to survive buttstroking someone with enough authority to actually hurt them. (Along those same lines, it would have a bayonet mount).

    I want it to have quality iron sights built into the design (probably a carry handle type arrangement, like most bullpups) but also have a sturdy mount for optics. Ideally I'd have an ACOG scope that was mounted in such a way that I could also use the iron sights; a see through mount. A raised cheekpiece would be built into the stock.

    I don't want the length of pull to be too excessive; many bullpups seem built for people with ape arms.

    Barrel length should be a full 20-22" while keeping the overall length under 40".

    The weapon should have provision for mounting a bipod that does NOT hang off of the barrel (like the FAMAS bipod, for example).

    SO....! Who else would want one?
     
  2. Schuey2002

    Schuey2002 Member

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    I'll take one. You payin'?!?!?! :D
     
  3. tire iron

    tire iron Member

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    I think you pretty well have it covered.

    The only thing I would add is a button up by the trigger that was connected to the magazine catch - so one could 'dump' an empty mag with the 'strong' hand while the weak hand goes for a full magazine.

    The way other bullpups work these days is one's hand MUST go to the magazine location with the weak hand and manipulate the magazine catch and extract the magazine. This works fine when one has the time to do that - but it not the fastest way to change mags.

    Great idea - but I won't hold my breath on this one.

    cheers

    tire iron
     
  4. Correia

    Correia Moderator Emeritus

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    Night, you have got a couple of things standing in your way from a design perspective. (and as you know the behind the scenes you know I've put a bit of time into this thought process!) :)

    The crime bill kind of screws up domestic designers because we need to design around existing magazines. Right now the most affordable .308 magazines out there are for the FAL. So if you design something that takes FAL magazines it needs to be a rock and lock kind of system as opposed to the straight in, straight out (AR mag). So you need to have room in the LOP for the long .308 length receiver, and you need the pistol grip far enough forward that you still have room to rock the magazine forward into place.

    Downward ejection probably ain't going to happen with a .308 bullpup. You can do forward ejection, but that requires some serious from the ground up design and some super dooper machine time. :p If you were not limited by the crime bill you could design a pan feed or something P90 like that would sit ontop of the action, but then you are dealing with the large size of the .308 round.

    My first .308 bullpup prototype was downward ejection. However it was only an 8 shot design. It was based on the M1 Garand action, only flipped upside down. You inserted the En Bloc clip through the bottom of the buttstock, and ejection was downwards. The reason I shelved it was because the line of sight was massively high above the bore. ( take your Garand action out of the stock some time, flip it upside down, and place your cheek above the magwell and you get an idea of what I was seeing). I tell you that you feel really stupid after about 20 hours of coming up with a good trigger pull for an upside down bullpup Garand only to realize that the thing is pretty much useless anyway. :D

    So to reach your stated goals your best bet would be forward ejection, and a AR10 style magwell. LOP is still going to be a touch long. Measure a .308 receiver and you can see what I mean. Forward ejection can be achieved through the use of a casing lifter during extraction, then as the bolt travels forward it gets shoved out the front of the action. (like the FN2000)

    Now to do this you are going to need to design the action from the ground up. That is where the cash comes in. If you happen to have an extreamly large chunk of money laying around somewhere just let me know and I've got the blueprints around here somewhere. :)
     
  5. Andrew Wyatt

    Andrew Wyatt Member

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    What about having the magazine location be 30 degrees from vertical, with two magazine wells. the weapon ejects downward. to change sides, remove the magazine and install it in the other magazine well. alternatively, you could go with a rotary magazine design like the johnson. put the magazine atop the weapon, and feed the strippers through the top or side.


    while you're at it, can you build me a mini-14 with a johnson style rotary magazine?
     
  6. Knife_Sniper

    Knife_Sniper Member

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    Offset magazine, eject downward to side of magazine.
    Their you go, ambidextrous. Needs some R&D.

    Trigger? Why not use an "electronic" trigger that creates a charge in the same way fireplace lighters work when you pull their triggers? Just find a way to route that to the primer through the firing pin and boom. Instant lock time with the trigger however you want it. Of course, it would be semi and you would have to worry about grounding out and water.

    I thought of a good trigger linkage a long time ago involving R/C car ball joints, and plastic end caps. Almost NO play if you used metal ball joints and the captured them with a nut. Also, trigger could by adjusted by turning the tie rod connected to both caps and making it shorter or longer, thus the amount of pull required would be shorter.

    I know you have absolutely no idea what im talking about.
    It makes sense in my head, all of it!
    :scrutiny:
     
  7. Destructo6

    Destructo6 Member

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    I like the idea of a ball-jointed trigger linkage setup with a turnbuckle thrown in for adjustment. The pivot points have to be tight, though or the whole setup will be sloppy.

    Why not a 7.62x51 version of FN's F2000? It ejects spent cases forward, so it would be equally friendly to all.
     
  8. Andrew Wyatt

    Andrew Wyatt Member

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    forward ejection = evil.

    if you have a stoppage, you have to dissassemble the gun to clear it.
     
  9. Nightcrawler

    Nightcrawler Member

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    Is there any reason you couldn't, as was suggested, put a downward ejection port right next to the magazine well? (The mag well'd be funneled so you wounldn't be trying to stuff the fresh magazine into the ejection port during a quick reload).

    The weapon would have to be a little bit wider, but it wouldn't matter any, really.

    Take the M249 SAW, for instance. When using the M16 magazines (assuming it works), it feeds from the lower left and ejects to the lower right. You could probably rotate both the magazine and the ejection so they're vertical. It'd require a well-designed ejector, though.
     
  10. George Hill

    George Hill Member

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    Other ways to look at it... Instead of a pan style mag system like a P-90 or a Lewis... why not a rotary mag like a Calico or Bizon? (just use flat nosed bullets instead of sharp points)
    Hmmm... then you would have that high sight problem that Correia already mentioned with his inverted M1 system.

    To be truthful, I really don't see the advantage of requiring a down eject.
    Just make the bolt and ejector reversable. Simple. Done. There is no need to make it more complicated than it has to be. The best gun designs are not the more clever ones, but the most elegantly simple.
     
  11. Andrew Wyatt

    Andrew Wyatt Member

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    you don't have to use flat pointed bullets. Calico made a couple models of 5.56mm assault rifles.
     
  12. George Hill

    George Hill Member

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    Serious?
    I did not know that.
     
  13. Correia

    Correia Moderator Emeritus

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    These are all great theories, the hard part is making them work. :)

    Andrew, the only reason you would have to take the gun apart to clear a malfunction on forward eject is because it was designed that way. It isn't any weirder than side ejection, it just isn't what we are used to. But since there are only 2 designs on earth that do this, and none of us have ever seen either it is all pretty much conjecture. If the receiver is designed in a matter that the ejection port is reachable then it will be clearable.

    Downward ejection with angled mag insertion, I've thought about it a lot, but I think what kills you is that during the extraction and ejection it is going to be really easy for the shell casing to bounce back into the action instead of down and out. Same reason you just don't have some sort of cover over the ejection port of an existing right ejection bullpup. I imagine that an ejector design could be made that would work, but I can't visualize exactly how.
     
  14. Andrew Wyatt

    Andrew Wyatt Member

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    I don't see what you're getting at, larry. the ejection port would be open to the air and there'd be a straight path to the ground. My idea was to have the magazine on the top of the gun. thving the magazine at an angle on the bottom would probably be better, since you'd only need one mag well.
     
  15. Nightcrawler

    Nightcrawler Member

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    Well, George, I'd be quite content with a side-ejecting bullpup that could be reversed for lefties. The trouble with those occurs in those few instances where it's handy to fire from the off shoulder, such as when you're laying prone behind cover, say a wall.

    Other than that though...

    In any case a lot of countries seem to make the bullpup work. Singapore, Australia, Austria, the UK, China, and France, to name a few.
     
  16. Correia

    Correia Moderator Emeritus

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    Andrew, I'm confused, if you are talking top feed with a traditional magazine (like a BREN) then you can't have a cheek weld.

    I was thinking something like this. Imagine an inverted V. This is the gun, viewed from the rear. The point of the V is the action. One leg is the magazine, the other leg is the ejection path.

    If you have the magazine on the left side with downward to the right ejection your are going to have the magazine turned into your body when you take up your stance. If you rotate the V until the magazine doesn't hit you in the body then your are starting to eject more and more out the side, which is what you are trying to avoid. If you design the gun to deflect the shells downward then I'm afraid that it would be easy to bounce casings back into the action.
     
  17. Nightcrawler

    Nightcrawler Member

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    Correia, is there any reason, as was suggested, that a configuration couldn't be worked where the magazine would feed vertically into a well, and the ejection would be downward directly to the side of the well? I mean, surely it's not IMPOSSIBLE to design this? (Don't have the R&D resources, obviously, but still)
     
  18. Knife_Sniper

    Knife_Sniper Member

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    Make it eject downwards toward the user, and have the cases deflected by a shell deflector. Bam, it ejects forward by ejecting backwards. Kinda like an AR turned sideways.
     
  19. corncob

    corncob Member

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    I've been working on a design for a commercially-viable bullpup deer rifle for a while now, and this is what I've decided:

    1. I thought of the inverted V configuration, but I ruled it out because the spent cases will hit your arms and burn them. Point your rifly and note where the path of the cases goes.

    2. If you plan on using 20 or 30-round mags (or whatever) the mag needs to protrude from the bottom of the rifle vertically. They are heavy when full, and you can't simply add weight to the other side of the rifle to balance it because they get lighter as you empty them.

    3. The only way to manufacture these cheaply enough to sell requires a design that eliminates a lot of the machining used in most guns.

    Any way you slice it, it is tough proposition, even before you start talking about the trigger linkage, which must be as good as the other (cheaper) traditional rifles on the rack if you want to sell it at all.
     
  20. Andrew Wyatt

    Andrew Wyatt Member

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    Imagine a bren with the magazine entering the weapon at the 10 o clock position. or the 2 o clock position.
     
  21. Correia

    Correia Moderator Emeritus

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    Knife sniper, and those forward flying cases under the gun are going to go where? Picture where your hand and arm are holding the pistol grip please. :)

    Night, if it is possible it needs to come from somebody a whole lot smarter than me. Try to visualize it with me. Say the mag is vertical on the left, on the right, parrallel to the mag is the ejection port. The spent casing will need to extract, be moved to the right, then shoved downward, all while not bouncing around and causing a malfunction. This would have to be a pretty well controlled action to accomplish this. If you watch a regular action it is a pretty violent and straight forward system.

    I imgine that it could be done, but it would be a complex system, and great care would have to be taken to get it to work reliably. That calls for some serious $. :)
     
  22. Correia

    Correia Moderator Emeritus

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    Andy, that would preclude a cheek weld, or at best make the gun so that it couldn't be used ambidextrously and thereby defeat the purpose of making it downward ejecting.
     
  23. Andrew Wyatt

    Andrew Wyatt Member

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    hence the two magazine wells. if you really feel you neeed to switch sides, just move the magazine to the other well.
     
  24. Badger Arms

    Badger Arms Member

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    The Steyr ACR is already an ambidexterous bullpup. It does have bottom ejection, but uses a ringfire ignition system and a unique breaching system. I think it fires from the open bolt of necessity, but I could be wrong. Just to give you an idea of the layout, though, the magazine has to be far to the rear in order for it to work properly. One thing that annoys me with my Ithaca 37 is that casings are thrown forcefully, and I do mean FORCEFULLY against my leg and foot when I eject them. Not bad with empties, but can bruise with live rounds. I'd imagine that if ejection force were not controlled, injuries can occur with a bottom-eject semi-auto.

    http://www.steyr-aug.com/acr2002.htm

    [​IMG]
     
  25. Nightcrawler

    Nightcrawler Member

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    Now, if the ACR were to be up-calibered they might be on to something.

    Dunno how a flechette round would perform compared to a regular spitzer bullet, though.
     
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