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Posted: 1/9/2014 4:08:53 PM EST
I did a rough up showing that you could fit the guts of an AR15 into a bull pup. The trick is relocating the recoil springs but i didn't include those details. The first one is a 20 in barrel and the second one is a 14.5. Let me know your thoughts.

http://i.imgur.com/huQJ6Ze.jpg
http://i.imgur.com/GemXbfk.jpg
http://i.imgur.com/iIY7MT6.jpg
http://i.imgur.com/iwodRTV.jpg
http://i.imgur.com/zcjFDuS.jpg
Link Posted: 1/9/2014 4:18:42 PM EST
[#1]
So the BCG has no room to move at all..... looks like a fail to me.
Link Posted: 1/9/2014 4:31:44 PM EST
[#2]
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Quoted:
So the BCG has no room to move at all..... looks like a fail to me.
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The BCG is shown in its rearmost position, out of battery and ready to strip a fresh round if not being held by the bolt catch.
Link Posted: 1/9/2014 4:33:11 PM EST
[#3]
The bcg looks to be locked and back...notice the space from the end of the barrel.
Link Posted: 1/9/2014 5:41:15 PM EST
[#4]
If you build it they will come - especially if you manage to use milspec lower receivers so what you sell is not a firearm.

I think the longziz #1 is ahead of you though....
Link Posted: 1/9/2014 5:58:14 PM EST
[#5]


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Quoted:
The BCG is shown in its rearmost position, out of battery and ready to strip a fresh round if not being held by the bolt catch.
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Quoted:





Quoted:


So the BCG has no room to move at all..... looks like a fail to me.






The BCG is shown in its rearmost position, out of battery and ready to strip a fresh round if not being held by the bolt catch.
Missing space for a buffer & spring... However there are some "AR"s that have done away with the buffer tube by using a piston system & severely modding the bcg
Link Posted: 1/9/2014 5:58:33 PM EST
[#6]
You forgot the buffer.
Link Posted: 1/9/2014 6:00:18 PM EST
[#7]
Figure out what you're going to do with the spring(s) yet, since you don't seem to want to put them on top or out front?
Link Posted: 1/9/2014 6:00:48 PM EST
[#8]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
If you build it they will come - especially if you manage to use milspec lower receivers so what you sell is not a firearm.

I think the longziz #1 is ahead of you though....
View Quote


I was thinking easy to make plastic lower (3d printer)…still working details. I really wish someone had this already.
Link Posted: 1/9/2014 6:06:36 PM EST
[#9]
Why not make it using the Para USA type upper so you dont need the recoil spring behind the BCG.
Link Posted: 1/9/2014 6:06:46 PM EST
[#10]
Gas may be an issue with di. Proximity to the face and lack of heat dissapation inside a plastic stock mostly.  A piston seems necessary.
Link Posted: 1/9/2014 6:07:42 PM EST
[#11]
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Quoted:
Figure out what you're going to do with the spring(s) yet, since you don't seem to want to put them on top or out front?
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Right now i'm making space for long small diameter, diametrically opposed, drawbar springs at 10 and 4 viewed from the back. I'm still trying to look for a better place tho so it could have a drop in left hand bcg without swapping the springs.
Link Posted: 1/9/2014 6:08:30 PM EST
[#12]
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Quoted:


I was thinking easy to make plastic lower (3d printer)…still working details. I really wish someone had this already.
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Quoted:
Quoted:
If you build it they will come - especially if you manage to use milspec lower receivers so what you sell is not a firearm.

I think the longziz #1 is ahead of you though....


I was thinking easy to make plastic lower (3d printer)…still working details. I really wish someone had this already.



Buy a Bushmaster
Link Posted: 1/9/2014 6:12:26 PM EST
[#13]
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Quoted:
Buy a Bushmaster
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True, but I am in love with DI. I think its such a cool idea.
Link Posted: 1/9/2014 6:12:31 PM EST
[#14]
Probably easier to design a new firearm altogether then try to fit an existing one into another form...
Link Posted: 1/9/2014 6:20:49 PM EST
[#15]
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Quoted:
Probably easier to design a new firearm altogether then try to fit an existing one into another form...
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I can tell you without a doubt it would be.
Link Posted: 1/9/2014 6:28:21 PM EST
[#16]
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Quoted:
Probably easier to design a new firearm altogether then try to fit an existing one into another form...
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Prob what IWI thought when designing the Tavor
Link Posted: 1/9/2014 6:37:07 PM EST
[#17]
Having the drive system at 12 o'clock bothers me.  Will lead to Tavorish optics height.  Needs to be clocked over to the side. Kinda like the AUG.  Getting visions of sten like side mags or tubes.
Link Posted: 1/9/2014 6:41:37 PM EST
[#18]
Why build a bullpup AR?  Design one around the guts of the SCAR 16.
Link Posted: 1/9/2014 6:45:23 PM EST
[#19]

Link Posted: 1/9/2014 6:52:41 PM EST
[#20]
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Wonder if he is still working on that? I love the design and universal mags.
Link Posted: 1/9/2014 6:55:12 PM EST
[#21]
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Why build a bullpup AR?  Design one around the guts of the SCAR 16.
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But without a reciprocating charging handle
Link Posted: 1/9/2014 7:07:12 PM EST
[#23]
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Quoted:


Right now i'm making space for long small diameter, diametrically opposed, drawbar springs at 10 and 4 viewed from the back. I'm still trying to look for a better place tho so it could have a drop in left hand bcg without swapping the springs.
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Quoted:
Quoted:
Figure out what you're going to do with the spring(s) yet, since you don't seem to want to put them on top or out front?


Right now i'm making space for long small diameter, diametrically opposed, drawbar springs at 10 and 4 viewed from the back. I'm still trying to look for a better place tho so it could have a drop in left hand bcg without swapping the springs.


That sounds familiar...

So how about positions for 4 springs and you only use the 2 diametrically opposed pair that works for the side you want the ejection on.  So 10 and 4 for right handed carrier, and the left carrier comes with it's own set of springs at 2 and 8.  Inside the receiver all 4 grooves are present, only two are used any any given time.  And of course you have some way to swap the ejection port cover.

The springs will need guides and it might make sense to attach them to a plate or plug at the rear.  That plug could also have a bumper built into it.  You will need some sort of hard stop at the rear.
Link Posted: 1/9/2014 7:13:58 PM EST
[#24]
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Quoted:
Gas may be an issue with di. Proximity to the face and lack of heat dissapation inside a plastic stock mostly.  A piston seems necessary.
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Unfortunately, he may be right.

Oh, and how will you charge it?  This is a good reason for the springs up front around the gas tube/key or piston.  If the handle is on the carrier, then it will have to be on the same side as the ejection port.  Which makes for awkward charging with the off hand.   And it makes another opening that you will need to close when swapping to the other side, else a guarantee of gas in the face.
Link Posted: 1/9/2014 8:12:03 PM EST
[#25]
I thought of doing one for a .22LR build. No need for the buffer and spring.
Link Posted: 1/9/2014 10:46:24 PM EST
[#26]
It would be much easier to convert a Rock River PDS to a bullpup configuration than a standard AR15
Link Posted: 1/10/2014 1:42:42 AM EST
[#27]
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Gas may be an issue with di. Proximity to the face and lack of heat dissapation inside a plastic stock mostly.  A piston seems necessary.
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The gas puff is still directed away from the face. The proximity to the face is about the same as a carbine with a collapsed stock. The barrel gets very hot also, but heat shielding allows the use of plastics. You would expose some of the metal receiver and shield any portion you need to.
Link Posted: 1/10/2014 1:51:29 AM EST
[#28]
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Quoted:

That sounds familiar...

So how about positions for 4 springs and you only use the 2 diametrically opposed pair that works for the side you want the ejection on.  So 10 and 4 for right handed carrier, and the left carrier comes with it's own set of springs at 2 and 8.  Inside the receiver all 4 grooves are present, only two are used any any given time.  And of course you have some way to swap the ejection port cover.

The springs will need guides and it might make sense to attach them to a plate or plug at the rear.  That plug could also have a bumper built into it.  You will need some sort of hard stop at the rear.
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I was thinking the same. I just wish you didn't have to mess with the springs to change the ejection.  The forward assist/case deflector would also need to be interchangeable.
Link Posted: 1/10/2014 5:22:22 AM EST
[#29]
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Quoted:
It would be much easier to convert a Rock River PDS to a bullpup configuration than a standard AR15
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Or use that "EXTAR" pistol that New Frontier Arms is manufacturing.
Link Posted: 1/10/2014 7:40:49 AM EST
[#30]

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Quoted:
Wonder if he is still working on that? I love the design and universal mags.
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Quoted:









Wonder if he is still working on that? I love the design and universal mags.
He made a post in the AR mag forum sometime last year. I asked him about the bull pup and he said something like he hasnt had a lot of time to work on it

 
Link Posted: 1/10/2014 8:10:35 AM EST
[#31]
ACE Riflestocks had a really neat prototype for a AR bullpup at their booth at SHOT almost a decade ago. I am surprised it never made it to the market.
Link Posted: 1/10/2014 9:38:38 AM EST
[#32]
How is that still an AR?
Link Posted: 1/10/2014 9:41:38 AM EST
[#33]
Longliz #1?
Link Posted: 1/10/2014 3:31:42 PM EST
[#34]
As far as the spring, think AK. Machine a gas key with the ability to accept a spring guide rod just above the gas port in the key. The rod with spring around it would be supported internally in the stock at the rear. I would use a plastic buffer at the rear of the stock for the BCG to slam into and as far as the standard AR Buffer weights, why not incorporate that into the rear hollow of the BCG?

Those buffer weights are critical in delaying the carrier long enough for pressure to subside in the case.
Link Posted: 1/10/2014 4:52:41 PM EST
[#35]
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Quoted:
How is that still an AR?
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At that point it really isn't an AR-15, it is just a new bullpup that uses AR components!  

Nothing wrong with that as you get parts availability and compatibility, but yeah, I would have to agree it really isn't an AR-15 all that much at that point.

Honestly, trying to shoehorn in AR components and move around the recoil assembly- at some point it really is easier to start from scratch and not be locked in by all the design constraints you inherently pick up by using off the shelf parts from an AR-15.
Link Posted: 1/10/2014 5:22:33 PM EST
[#36]
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Quoted:
As far as the spring, think AK. Machine a gas key with the ability to accept a spring guide rod just above the gas port in the key. The rod with spring around it would be supported internally in the stock at the rear. I would use a plastic buffer at the rear of the stock for the BCG to slam into and as far as the standard AR Buffer weights, why not incorporate that into the rear hollow of the BCG?

Those buffer weights are critical in delaying the carrier long enough for pressure to subside in the case.
View Quote


The buffer weights in the carrier make the extra length useful so i agree.
Link Posted: 1/10/2014 6:45:58 PM EST
[#38]
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Quoted:


I was thinking the same. I just wish you didn't have to mess with the springs to change the ejection.  The forward assist/case deflector would also need to be interchangeable.
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Quoted:
Quoted:

That sounds familiar...

So how about positions for 4 springs and you only use the 2 diametrically opposed pair that works for the side you want the ejection on.  So 10 and 4 for right handed carrier, and the left carrier comes with it's own set of springs at 2 and 8.  Inside the receiver all 4 grooves are present, only two are used any any given time.  And of course you have some way to swap the ejection port cover.

The springs will need guides and it might make sense to attach them to a plate or plug at the rear.  That plug could also have a bumper built into it.  You will need some sort of hard stop at the rear.


I was thinking the same. I just wish you didn't have to mess with the springs to change the ejection.  The forward assist/case deflector would also need to be interchangeable.


And I wish you didn't have to change the carrier and bolt.  But since you do, it isn't a big deal to swap the springs at the same time.  If the rear plate didn't need indexing to keep the spring guide rods in alignment, you could use the same spring set, just slide it onto the lefty carrier in the proper position.

FA?  Case deflector?  What are those?  Most guns don't have or need an FA, and a case deflector is for lefties shooting a right handed bolt.  That isn't going to happen with your design, unless the shooter likes cheek burns.  Don't invent problems that you don't have.  Or do, like how in the hell am I going to get forward eject to work with a gas tube in the way and not modifying the bolt... or including any other unnecessary features.
Link Posted: 1/10/2014 6:50:11 PM EST
[#39]
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Quoted:


The buffer weights in the carrier make the extra length useful so i agree.
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Quoted:
Quoted:
As far as the spring, think AK. Machine a gas key with the ability to accept a spring guide rod just above the gas port in the key. The rod with spring around it would be supported internally in the stock at the rear. I would use a plastic buffer at the rear of the stock for the BCG to slam into and as far as the standard AR Buffer weights, why not incorporate that into the rear hollow of the BCG?

Those buffer weights are critical in delaying the carrier long enough for pressure to subside in the case.


The buffer weights in the carrier make the extra length useful so i agree.


This?
Link Posted: 1/11/2014 2:34:43 AM EST
[#40]
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Quoted:

And I wish you didn't have to change the carrier and bolt.  But since you do, it isn't a big deal to swap the springs at the same time.  If the rear plate didn't need indexing to keep the spring guide rods in alignment, you could use the same spring set, just slide it onto the lefty carrier in the proper position.

FA?  Case deflector?  What are those?  Most guns don't have or need an FA, and a case deflector is for lefties shooting a right handed bolt.  That isn't going to happen with your design, unless the shooter likes cheek burns.  Don't invent problems that you don't have.  Or do, like how in the hell am I going to get forward eject to work with a gas tube in the way and not modifying the bolt... or including any other unnecessary features.
View Quote


With the springs I won't argue. It just means the springs have to be easy to swap. (this should be done any way)

I agree with your other points, however, I have learned a painful lesson during my years in designing other systems that if a feature could be potentially useful but not necessary include it in the design phase and only eliminate it at the end. Also don't eliminate the feature in a way that it can't be brought back. Thats really just a philosophical difference.

On the case deflector in particular my thoughts are a cheek burn is possible depending on where the lefty puts his face on the rifle. Without some type of deflector, getting hit in the neck with brass AND getting a cheek burn is worse than a cheek burn alone.

Also I'm thinking drawbar springs at this point so the spring guides can be thought of as being assembled with the springs…think AK47.

Link Posted: 1/11/2014 2:40:12 AM EST
[#41]
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Quoted:


This?
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Quoted:
Quoted:
Quoted:
As far as the spring, think AK. Machine a gas key with the ability to accept a spring guide rod just above the gas port in the key. The rod with spring around it would be supported internally in the stock at the rear. I would use a plastic buffer at the rear of the stock for the BCG to slam into and as far as the standard AR Buffer weights, why not incorporate that into the rear hollow of the BCG?

Those buffer weights are critical in delaying the carrier long enough for pressure to subside in the case.


The buffer weights in the carrier make the extra length useful so i agree.


This?


Ya, that, just the little weight would need some play to slam forward after the bolt closes.
Link Posted: 1/11/2014 3:18:16 AM EST
[#42]
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I spent a lot of time following up on that…there seems to be a complete blackout on that rifle and exactly how it works.
Link Posted: 1/11/2014 9:26:54 AM EST
[#43]
I would bet they copied the ZM, as it is proven, and there is no recourse to sue them.  A piston could also be done, using a similar keyed end to capture the forward end of the spring (in this case, it would also serve as the piston head).
Link Posted: 1/11/2014 9:37:26 AM EST
[#44]
ACE Ltd. was working on a bullpup AR back in 2006.  I can't find it on their website any more, but here's a photo I found on another site:



 I have no idea if/how they linked that trigger to the fire control group.

Link Posted: 1/11/2014 10:49:05 AM EST
[#45]
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Quoted:


With the springs I won't argue. It just means the springs have to be easy to swap. (this should be done any way)

I agree with your other points, however, I have learned a painful lesson during my years in designing other systems that if a feature could be potentially useful but not necessary include it in the design phase and only eliminate it at the end. Also don't eliminate the feature in a way that it can't be brought back. Thats really just a philosophical difference.

On the case deflector in particular my thoughts are a cheek burn is possible depending on where the lefty puts his face on the rifle. Without some type of deflector, getting hit in the neck with brass AND getting a cheek burn is worse than a cheek burn alone.

Also I'm thinking drawbar springs at this point so the spring guides can be thought of as being assembled with the springs…think AK47.
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Quoted:
Quoted:

And I wish you didn't have to change the carrier and bolt.  But since you do, it isn't a big deal to swap the springs at the same time.  If the rear plate didn't need indexing to keep the spring guide rods in alignment, you could use the same spring set, just slide it onto the lefty carrier in the proper position.

FA?  Case deflector?  What are those?  Most guns don't have or need an FA, and a case deflector is for lefties shooting a right handed bolt.  That isn't going to happen with your design, unless the shooter likes cheek burns.  Don't invent problems that you don't have.  Or do, like how in the hell am I going to get forward eject to work with a gas tube in the way and not modifying the bolt... or including any other unnecessary features.


With the springs I won't argue. It just means the springs have to be easy to swap. (this should be done any way)

I agree with your other points, however, I have learned a painful lesson during my years in designing other systems that if a feature could be potentially useful but not necessary include it in the design phase and only eliminate it at the end. Also don't eliminate the feature in a way that it can't be brought back. Thats really just a philosophical difference.

On the case deflector in particular my thoughts are a cheek burn is possible depending on where the lefty puts his face on the rifle. Without some type of deflector, getting hit in the neck with brass AND getting a cheek burn is worse than a cheek burn alone.

Also I'm thinking drawbar springs at this point so the spring guides can be thought of as being assembled with the springs…think AK47.


I hope you don't taking my posts personally, I am just trying to point out things you may not have thought of, and to educate myself about new (to me) engineering concepts.  I would love to see a bullpup based on the AR15, and was hoping that Longziz didn't fall off of the map.  My guess is that he was hired by someone and now has the backing to bring it to fruition.

1) I am confused with the draw bar concept.  Is it functionally different than the AR18 spring setup, basically a plate with two guide rods and springs on it?  My thoughts are two relatively narrow guide rods extending forward from a rear plate, and the plate has a bumper incorporated into it.  The springs ride on the rods, and lay alongside the carrier in grooves on it and in the receiver  Or since you are making your own receiver, solely in the receiver.  If you do what some have done, access is thru the rear buttplate, you slide the spring assy out, followed by the carrier, slide in the lefty carrier, followed by the same spring assy, rotated to the correct grooves.  The rear plate can have 2 or 4 indexing notches for both left and right rotational positions, and 1 or 2 keys in the stock, each indexed for either the left or right position, and marked with an (wait for it...) R and L to know which rotational position to use.  What captures the springs up front to compress them?  I have the springs riding in grooves, part of the groove is on the carrier, the other part in the receiver.  And a stud screwed into either side of the front of the carrier, with a hole for the guide rod to pass through, the stud capturing the front of the spring and does the compressing during cycling.  Right side eject carrier uses the 10 and 4 grooves in the receiver, left eject uses the 2 and 8 position grooves.

2) Since we are talking bullpup, I assume we are in agreement that the ejection port needs to be swapped, the 'other' port closed due to face proximity, etc.  Since we are swapping port to the appropriate side for the shooter, what function does a deflector have?  It allows weak side (opposite shoulder) shooting without getting brass in the face in the AR15. Considering that the ejection port is going to be under the cheek, weak side shooting will be problematic at best, even with a deflector.

3) FA is a contentious feature, and even Knights (numerous others) doesn't have them on their 308 guns.  I suspect they do have them on the 5.56 guns as it is a milspec feature in 5.56 caliber rifles and is already on the forgings they use. That said, since the bolt is so close to the face and you aren't relocating the springs forward, the FA you come up with is going to be a pain in the a$$ to implement, and possibly to use as well.  OK, I take that back.  As long as you allow that you have to remove the rifle from shooting position (not ideal, but workable), you can have it on the left side in the exact same position in relation to the carrier that is is now,  and you don't have to swap it.  iirc, Stag's FA doesn't swap, thus the carrier has the same notches as a standard carrier.  So when you shoot left handed, the FA should be just behind where your cheek rests, right?  Shooting from either side, you would have to pull the rifle away from you to operate it, but it would be the same parts as an AR and use the existing notches on the carrier.

4) If you have already listed it, refresh my memory on the charging handle solution.  Recip or not?  Either way, again, with nothing extending forward of the bolt head attached to the carrier, the slot that the handle operates in will be alongside the face, and thus dumping gas where you don't want it (alongside the face).  And it will be another thing to fill/cover when you swap sides.   It will have to be on the opposite side the stock from the face, and being up next to your face, it won't be in the most ergonomic location to operate.  Like the FA, you may find pulling the rifle out of firing position to operate it is the most comfortable.

5)  I am not saying your design won't work, but you aren't doing yourself any favors with it, except retaining a few parts for commonality with the AR15 platform.
Link Posted: 1/11/2014 12:10:47 PM EST
[#46]
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Quoted:


I hope you don't taking my posts personally, I am just trying to point out things you may not have thought of, and to educate myself about new (to me) engineering concepts.  I would love to see a bullpup based on the AR15, and was hoping that Longziz didn't fall off of the map.  My guess is that he was hired by someone and now has the backing to bring it to fruition.

1) I am confused with the draw bar concept.  Is it functionally different than the AR18 spring setup, basically a plate with two guide rods and springs on it?  My thoughts are two relatively narrow guide rods extending forward from a rear plate, and the plate has a bumper incorporated into it.  The springs ride on the rods, and lay alongside the carrier in grooves on it and in the receiver  Or since you are making your own receiver, solely in the receiver.  If you do what some have done, access is thru the rear buttplate, you slide the spring assy out, followed by the carrier, slide in the lefty carrier, followed by the same spring assy, rotated to the correct grooves.  The rear plate can have 2 or 4 indexing notches for both left and right rotational positions, and 1 or 2 keys in the stock, each indexed for either the left or right position, and marked with an (wait for it...) R and L to know which rotational position to use.  What captures the springs up front to compress them?  I have the springs riding in grooves, part of the groove is on the carrier, the other part in the receiver.  And a stud screwed into either side of the front of the carrier, with a hole for the guide rod to pass through, the stud capturing the front of the spring and does the compressing during cycling.  Right side eject carrier uses the 10 and 4 grooves in the receiver, left eject uses the 2 and 8 position grooves.

II don't blame you for being confused. I have not shared any real pictures yet. However yes the drawbar is completely different than the ar 18 concept. Just google "drawbar spring". Its a type of extension spring. The extension spring would connect to the  back of a "carrier catcher" plate. You would have no grooves in the receiver. the drawbar springs would span from about the FSB to the back of the carrier (very long). You may need an eyelet somewhere in between to ensure the coiling spring doesn't knock the drawbars out of line , but other than that the drawbars are in tension so they are stable.


2) Since we are talking bullpup, I assume we are in agreement that the ejection port needs to be swapped, the 'other' port closed due to face proximity, etc.  Since we are swapping port to the appropriate side for the shooter, what function does a deflector have?  It allows weak side (opposite shoulder) shooting without getting brass in the face in the AR15. Considering that the ejection port is going to be under the cheek, weak side shooting will be problematic at best, even with a deflector.

I don't disagree totally one hidden benefit of the magazine being so far forward is the ejection is further forward. In what i'm proposing the ejection port is further forward than practically any other bull pup i have studied. When I put my dummy in there I don't find that the ejection port is under the cheek.

3) FA is a contentious feature, and even Knights (numerous others) doesn't have them on their 308 guns.  I suspect they do have them on the 5.56 guns as it is a milspec feature in 5.56 caliber rifles and is already on the forgings they use. That said, since the bolt is so close to the face and you aren't relocating the springs forward, the FA you come up with is going to be a pain in the a$$ to implement, and possibly to use as well.  OK, I take that back.  As long as you allow that you have to remove the rifle from shooting position (not ideal, but workable), you can have it on the left side in the exact same position in relation to the carrier that is is now,  and you don't have to swap it.  iirc, Stag's FA doesn't swap, thus the carrier has the same notches as a standard carrier.  So when you shoot left handed, the FA should be just behind where your cheek rests, right?  Shooting from either side, you would have to pull the rifle away from you to operate it, but it would be the same parts as an AR and use the existing notches on the carrier.

FA could be done with a reverse able subassembly plunger and pawl. or some type of reverse charging handle. I would leave room for whatever one is easier, but leave it out of a prototype

4) If you have already listed it, refresh my memory on the charging handle solution.  Recip or not?  Either way, again, with nothing extending forward of the bolt head attached to the carrier, the slot that the handle operates in will be alongside the face, and thus dumping gas where you don't want it (alongside the face).  And it will be another thing to fill/cover when you swap sides.   It will have to be on the opposite side the stock from the face, and being up next to your face, it won't be in the most ergonomic location to operate.  Like the FA, you may find pulling the rifle out of firing position to operate it is the most comfortable.

I'm working thru charging but i'm thinking of hooking the carrier catcher to the carrier and using a Tavor like pin to push it back. I have been thinking about this for a while but I didn't start designing until maybe a month or so ago after I modeled up an M4.  

5)  I am not saying your design won't work, but you aren't doing yourself any favors with it, except retaining a few parts for commonality with the AR15 platform.

I think saving the barrel, gas block, gas tube, bolt carrier group, bolt catch, fire control group is a majority of the working parts of the rifle. Only thing i'm throwing out is the recoil system and receivers. Even an m4 and m16 have different recoil systems…technically.  
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And I wish you didn't have to change the carrier and bolt.  But since you do, it isn't a big deal to swap the springs at the same time.  If the rear plate didn't need indexing to keep the spring guide rods in alignment, you could use the same spring set, just slide it onto the lefty carrier in the proper position.

FA?  Case deflector?  What are those?  Most guns don't have or need an FA, and a case deflector is for lefties shooting a right handed bolt.  That isn't going to happen with your design, unless the shooter likes cheek burns.  Don't invent problems that you don't have.  Or do, like how in the hell am I going to get forward eject to work with a gas tube in the way and not modifying the bolt... or including any other unnecessary features.


With the springs I won't argue. It just means the springs have to be easy to swap. (this should be done any way)

I agree with your other points, however, I have learned a painful lesson during my years in designing other systems that if a feature could be potentially useful but not necessary include it in the design phase and only eliminate it at the end. Also don't eliminate the feature in a way that it can't be brought back. Thats really just a philosophical difference.

On the case deflector in particular my thoughts are a cheek burn is possible depending on where the lefty puts his face on the rifle. Without some type of deflector, getting hit in the neck with brass AND getting a cheek burn is worse than a cheek burn alone.

Also I'm thinking drawbar springs at this point so the spring guides can be thought of as being assembled with the springs…think AK47.


I hope you don't taking my posts personally, I am just trying to point out things you may not have thought of, and to educate myself about new (to me) engineering concepts.  I would love to see a bullpup based on the AR15, and was hoping that Longziz didn't fall off of the map.  My guess is that he was hired by someone and now has the backing to bring it to fruition.

1) I am confused with the draw bar concept.  Is it functionally different than the AR18 spring setup, basically a plate with two guide rods and springs on it?  My thoughts are two relatively narrow guide rods extending forward from a rear plate, and the plate has a bumper incorporated into it.  The springs ride on the rods, and lay alongside the carrier in grooves on it and in the receiver  Or since you are making your own receiver, solely in the receiver.  If you do what some have done, access is thru the rear buttplate, you slide the spring assy out, followed by the carrier, slide in the lefty carrier, followed by the same spring assy, rotated to the correct grooves.  The rear plate can have 2 or 4 indexing notches for both left and right rotational positions, and 1 or 2 keys in the stock, each indexed for either the left or right position, and marked with an (wait for it...) R and L to know which rotational position to use.  What captures the springs up front to compress them?  I have the springs riding in grooves, part of the groove is on the carrier, the other part in the receiver.  And a stud screwed into either side of the front of the carrier, with a hole for the guide rod to pass through, the stud capturing the front of the spring and does the compressing during cycling.  Right side eject carrier uses the 10 and 4 grooves in the receiver, left eject uses the 2 and 8 position grooves.

II don't blame you for being confused. I have not shared any real pictures yet. However yes the drawbar is completely different than the ar 18 concept. Just google "drawbar spring". Its a type of extension spring. The extension spring would connect to the  back of a "carrier catcher" plate. You would have no grooves in the receiver. the drawbar springs would span from about the FSB to the back of the carrier (very long). You may need an eyelet somewhere in between to ensure the coiling spring doesn't knock the drawbars out of line , but other than that the drawbars are in tension so they are stable.


2) Since we are talking bullpup, I assume we are in agreement that the ejection port needs to be swapped, the 'other' port closed due to face proximity, etc.  Since we are swapping port to the appropriate side for the shooter, what function does a deflector have?  It allows weak side (opposite shoulder) shooting without getting brass in the face in the AR15. Considering that the ejection port is going to be under the cheek, weak side shooting will be problematic at best, even with a deflector.

I don't disagree totally one hidden benefit of the magazine being so far forward is the ejection is further forward. In what i'm proposing the ejection port is further forward than practically any other bull pup i have studied. When I put my dummy in there I don't find that the ejection port is under the cheek.

3) FA is a contentious feature, and even Knights (numerous others) doesn't have them on their 308 guns.  I suspect they do have them on the 5.56 guns as it is a milspec feature in 5.56 caliber rifles and is already on the forgings they use. That said, since the bolt is so close to the face and you aren't relocating the springs forward, the FA you come up with is going to be a pain in the a$$ to implement, and possibly to use as well.  OK, I take that back.  As long as you allow that you have to remove the rifle from shooting position (not ideal, but workable), you can have it on the left side in the exact same position in relation to the carrier that is is now,  and you don't have to swap it.  iirc, Stag's FA doesn't swap, thus the carrier has the same notches as a standard carrier.  So when you shoot left handed, the FA should be just behind where your cheek rests, right?  Shooting from either side, you would have to pull the rifle away from you to operate it, but it would be the same parts as an AR and use the existing notches on the carrier.

FA could be done with a reverse able subassembly plunger and pawl. or some type of reverse charging handle. I would leave room for whatever one is easier, but leave it out of a prototype

4) If you have already listed it, refresh my memory on the charging handle solution.  Recip or not?  Either way, again, with nothing extending forward of the bolt head attached to the carrier, the slot that the handle operates in will be alongside the face, and thus dumping gas where you don't want it (alongside the face).  And it will be another thing to fill/cover when you swap sides.   It will have to be on the opposite side the stock from the face, and being up next to your face, it won't be in the most ergonomic location to operate.  Like the FA, you may find pulling the rifle out of firing position to operate it is the most comfortable.

I'm working thru charging but i'm thinking of hooking the carrier catcher to the carrier and using a Tavor like pin to push it back. I have been thinking about this for a while but I didn't start designing until maybe a month or so ago after I modeled up an M4.  

5)  I am not saying your design won't work, but you aren't doing yourself any favors with it, except retaining a few parts for commonality with the AR15 platform.

I think saving the barrel, gas block, gas tube, bolt carrier group, bolt catch, fire control group is a majority of the working parts of the rifle. Only thing i'm throwing out is the recoil system and receivers. Even an m4 and m16 have different recoil systems…technically.  
Link Posted: 1/11/2014 12:15:09 PM EST
[#47]
Here is another picture I put together. It shows the size comparison to the baselines. http://i.imgur.com/iwodRTV.jpg
Link Posted: 1/11/2014 1:34:32 PM EST
[#48]
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Only thing i'm throwing out is the recoil system and receivers.
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Quite frankly, throwing out the lower receiver will IMNSHO kill it as a product.  Now you've become a firearms manufacturer, and you've gotten yourself into a huge mess of paperwork and delay.  Getting off the AR-15 lower-receiver "firearm" platform gets rid of a ton of the benefit of using AR-15 components....
Link Posted: 1/11/2014 2:52:51 PM EST
[#49]
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Quite frankly, throwing out the lower receiver will IMNSHO kill it as a product.  Now you've become a firearms manufacturer, and you've gotten yourself into a huge mess of paperwork and delay.  Getting off the AR-15 lower-receiver "firearm" platform gets rid of a ton of the benefit of using AR-15 components....
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Only thing i'm throwing out is the recoil system and receivers.


Quite frankly, throwing out the lower receiver will IMNSHO kill it as a product.  Now you've become a firearms manufacturer, and you've gotten yourself into a huge mess of paperwork and delay.  Getting off the AR-15 lower-receiver "firearm" platform gets rid of a ton of the benefit of using AR-15 components....


The lower being the "firearm" is only true from a bureaucratic and legal point of view. I couldn't care less about paperwork, do it all day long. I could do it if I really wanted to make a profit. I do just fine. I plan on making my own. No paperwork required.
Link Posted: 1/11/2014 4:10:52 PM EST
[#50]
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Quoted:
The lower being the "firearm" is only true from a bureaucratic and legal point of view. I couldn't care less about paperwork, do it all day long. I could do it if I really wanted to make a profit. I do just fine. I plan on making my own. No paperwork required.
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Fair enough - thus my comment about "as a product" - I misunderstood your intentions. Have fun.
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