Longziz, Log out of the site and log back in.  

oops, dbltap

Since you asked, I am not so sure now. I attended a firearm safety class in October this year. It is an all-German course and my German is really fundamental, so after the break I decided to quit. However, before that, the instructor did mention what are considered as firearm. He raised the slide, the barrel, the frame and the mag of a disassembled hand gun, as well as multiple parts he laid down on the top of a table, saying that all these are. Among them, I saw an AR15 pistol grip. May I got it wrong.

To be quite honest, due to my limited German and not knowing the law very well, I would prefer to play safe. However, that doesn't means to spreading the wrong message. So thanks for pointing this out. I need to do more homework.

Actually, when I was playing with my little design [over on another forum that was 6.5 Grendel focussed] I came up with just that solution.  I found that about a 30 to 45 degree stack angle narrowed it enough, while keeping the mag capacity up around 30 or 40 rounds.  Tinkered with an inverted Mini-14/30 mechanism and an inverted AUG schematic.  OAL for the smallest version, came out to around PDR/P90 sizes and I even toyed with the idea of a secondary feed setup so that a standard AR style mag could be used "Bren" style in a pinch.

this thread is awesome.

I'm so in for a kit.

To answer some of you guys question.

1. The rifle has multiple provisional patents filed.
2. The thumb hole. Originally I designed it with a pistol grip, using standard AR pistol grip or any other aftermarket one. However, by then, I was envision using aluminum sheet metal to build the shell, so the material can handle the recoil stress. However, since later I change my mind to use plastic or fiber glass, I was concerned about the strength at that area, so I changed the design to thumb hole. In a designer's mind, either way is fine. So I think whether it should go thumb hole or pistol grip is a marketing decision.
3. Safety. Other than the obvious AR safety, there are multiple safeties designed and implemented into the prototype rifle. For bolt there are two bolt head (fail to lock) safety design, one implemented in the rifle. This is to prevent that the somehow cam pin turned but the bolt head failed to lock with barrel extension. There are cheek piece disposition safety, which double served as cheek piece lock, will prevent the bolt been released and goes into battery, when the cheek piece is not locked in one of the two possible positions. Theoretically, if the switch latch is pull and the cheek piece is pushed out of the first position, you can release the latch and the bolt carrier group will not goes into battery until the cheek piece is locked in the second position. You guy probably notice that when I change the ejection to the left, the latch didn't return to its rest position. What happened is that the left locking mechanism has excessive friction and sometimes it is failed to return to locking position even the cheek piece is in position. This nevertheless created a reliability issue that needs to be studied further. All I can say for now is that it does the job.
4. Cheek piece. There are two cheek piece locking mechanism designed, and one implemented into the prototype rifle. When in the lock position, the switch mechanism are disengage from action. So even if the cheek piece was damaged by whatever reason, the only function lost is the switching function. The rifle is still fireable with last discharge configuration. However, tests are needed to prove all these.
5. Switching mechanism. When locked (cheek piece or bolt), it is not involved in normal firing function. Due to additional parts, failure mode of the bolt assembly are expect to be more than that of the standard AR15's. However, the most stress concentrated part of a bolt assemble is the bolt head, I envision the failure rate of my design only add a fraction of what is with the bolt head. Plus the implement of piston system, I envision it to be more reliable than a standard AR15. Again, tests are need to prove that.
6. Again Weight. As I said before, I didn't care to lower weight. It is a prototype, not a commercial version, weight didn't mean much to me by then. However, for the future commercial version, this is going to be a challenge. All I can say for now is that the prototype is HEAVY. Just like at the upper receiver and the rails, they weights a lot.
7. KB. Well, since I envision myself to be the first test technician, I put a lot of thought behind the design to avoid killing myself. However, that been said, I never experienced a KB and never saw one. I have seen a lot of picture of that online, however, those are static outcomes so it helped me little. All I can say is, due to the two ejection port and other opening, I envision if KB does happen, it at least has double venting path for the hot gas. I made the cheek piece extra large also for this reason. If somehow KB happens, the cheek piece would shield the debris from the shooter.
8. Trigger pull. Again, I didn't pay attention to it. I did minimum work to make it work. If I have the freedom to choose, I personally would implement KEL-TEC RFB design. I never lay my hand on one, but they look damn good on paper.

did I missing anyone?

Nice work out there. What material you used for the lower? Is the upper made by sheet metal? What happened for Magpul PDR?

It is always exciting to see innovation especially coming from a young engineer who is not already in the firearms industry. I wish you great sucess! Perhaps one day you will make it back to the US and be able to persue firearms design full time.

1. Would a window be required to display the AR15 lower recievers serial number?
2. Is the magazine well flared on your lower outer reciever?
3. How are the ergonomics using the angle of the AR15 reciever's magazine well in a bullpup design?
4. Have you considered crowd sourcing to generate start up capital?

1. If it is for commercial one, I would say it has to be, right?
2. Please don't check my poor fiber glass laying technique, but yes I think so (watching out)
3. I don't know what you mean.
4. Man, do I know you? Did you see my doctor thesis? Yes I did, but my boss killed the idea.

Well, well said Sir

That would be very interesting to see.  Dual feed options would be a first!!   (I'm sure that its not and someone will correct me..)

BEWARE of provisionals.  They need to be written to the same standards as any other patent application in order to be useful.

Also, they are "provisional applications", not "provisional patents".  You'll still need to get the applications through the system before you have solid protection.  Provisionals (assuming they are well-written) only set your priority date;  they provide no other protection.  We had a member here who got royally screwed a few years ago, I believe in part because of not fully recognizing the difference.

You mentioned working with a patent attorney,;  I hope he has talked with you about these issues.



Your thesis was on crowdsourcing??  I'd be interested in reading it if you would let me know how to find it.  The email link will reach me;  my IM box is overfull.

It's somewhat sad to me that the freedoms we Americans enjoy are too often taken for granted.   On the flip side, I'm damn proud that someone like the OP can come here and invent something like this.  Who knows where your invention will lead you, but I hope you follow it through.  You sir are welcome here and I hope you choose to stay.  Thank you for sharing!!

Tagscribe!

Continue the story.

Although I still have parts out of tolerance range, I finally assembled everything together. After a few teak I made the first switch with real rounds for the first time. Initially I could only make the bolt turn to left eject but not back to right. A real patient filing of the hardened bolt clear that final obstacle. I finally achieved the main goal of this trip. However, to make a completed rifle for a demo video, still more thing need to be done. Lower receiver shell took a big chunk of my time but it is finally done as well. Just one week before I scheduled departure day, I fired a spent casing with a fresh primer for the first time. It is a success. However, when I bring the rifle in to eject the casing, I found I couldn't rack the charging handle. My hand and arm had exceed the fatigue point for a long time and they were weak, but not 'that' weak. After some hassle, I managed ejecting the casing and immediately spot something is wrong. The primer is sticking out of its pocket. Oh no, the word "head spacing" jumped into my mind. Neither my friend or I have a 223 go or no-go gauge. I used the mask tape method and the result is whopping 0.025", 10 times than it is allowed!



Continuing the bolt work and hardening it and mating it with other parts wasn't fit into the time frame, I was already into the manufacturing of Longziz #2 and mooning for the Longziz #3. So I started to think about working on the barrel. After all, my design don't care if the gas port is upright. However, we couldn't find a suitable vise to clamp the barrel to keep it from turning when we wanted to unscrew the barrel extension. With the final day approaching and after weighing the risk associated with live fire, I decided stop short of firing it but paint it instead. I need it to look good!

So, here you have it. Longziz #1, and a full story behind it.

Congratulations, you have now made the FALFILES!!!

more!

The lower is Nylatron, similar to Nylon 6, and the upper is extruded aluminum oval, with the bottom radius milled off.
Magpul never built a working prototype of the PDR unfortunately...

http://www.ar15.com/forums/t_1_5/1258215_Homemade_Bullpup_with_AR_15_Lower_Receiver.html

 

1. My limited, laymans understanding is that yes the serial number would have to be visible externally.
3. What I mean is the angle of magazine insertion on a bullpup is not the same as the angle of insertion on a traditional AR15. Were magazine changes easy?
4. What is your thesis about?

This might be a tag. Great job OP.

I think it is great idea and would love to handle a final version. Being lefty I always felt "meh" about bullpups, but this has real promise.

^^^^yes

Looks damn good so far....TAG

You sir are a gentleman, and you beat me to it.  

Reminds me of:

Bushmaster was designing a bullpup ACR in 2010?

Good job. I wish I was smart enough to figure out 1/10 of what you have.

Been following this for a couple of days now. Really cool and can't wait to see progress as time goes on.

Posted Via AR15.Com Mobile

Those are badass

They are not real, some with photo shop created them

they did a hell of a job

COOL!
reminds me of the polish  MSBS 556

Does anyone here want to marry longziz to get him back here so he can finish this thing?  Maybe someone in Cali?

Very interested, I can almost guarantee that when you bring to market, if the quality is there, you will have a buyer here <-

Thats a sick looking platform. My only concern is with operating controls like the trigger, mag release and bolt catch.

Man, you are killing me! But thanks not MA or NY, at least Cali has some sunshine....

You are a good man! You are right, I fully aware of the difference. I am just not getting use to speak lawyer's language. My lawyer reviewed this thread and OK-ed it.

PS: My account can't generate email. You can PM me your email address.

3. I think it is OK, but since the position changed, I bet the feeling is different.
4. Open source product design.

Thank you sir! With you guys support, my hope is high.

Awesome, I see what you did there

Great thread, please keep us updated. Not to often one gets to follow the development of something new along with some thoughts/bio of the person behind the idea. Looks like an interesting concept, keep it going !!

YOU ARE A TEAM MEMBER!

My heart swells with pride.

You are more American than you think. I cant get over your attitude and appreciation. Many of us here strive to get the country back on track. Sorry if I've dwelled on this aspect, but Longziz, you can stay in my country any day. Plus if this thing gets big, you will hire some of us!

A free state! Someone from AZ or TX step up and marry this dude.

if this design works out for the  ar-15 platform ...will a 308 config be next ,it will sell very well !

Wow, not until Cavgunner mention it did I notice what changed! I guess I am slow in this regards. This is amazing! Totally out of my expectation. Thanks and I am honored!

Forgive me if I am wrong, but since I mentioned I found the woman of my life (hint married) in the previous post, I guess what he means is the special one available in Cali. But the dilemma is, I am straight and already married, Cali has to pass a new law to allow bi-marriage to make this works.

Did I just give them a new idea for free?

Thoroughly impressed. Amazing work.

Taggg

Thank you Sir! Lots of my friend in US are working hard on this, I mean the 'getting the country back on track' part. I, as a foreigner, will do my share to help, if possible.

This is amazing. If it could be done for the right price (not like the ACR) and works good, I would be in for at least one! Would love a bullpup rifle. Keep up the amazing work!

Nice work Longziz, I'd totally buy one of these. Get them produced!