Someone just bullpup'ed an AR-15 and succeeded.


November 26, 2011, 10:26 AM
It's called the Longziz #1 (

I looked for another forum or post where there might be more information on this and came up short. He says there is an AR-15 lower in that thing. I'm guessing that is an AR-15 barrel.

Hope he gets a range video up soon.

EDIT: Found more on this thing! ( From what I can tell he is using a completely new upper and blot. The upper I understood from the beginning but the bolt intrigues me.

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November 26, 2011, 11:05 AM
I sorta like the concept, love the inovations and the pursue of developments!

November 26, 2011, 11:11 AM
Very cool.

November 26, 2011, 11:31 AM
Near as I could tell, he said the AR15 bolt will work for for left/right eject, but he had to make a new bolt to work with the gas piston/bullpup design.

November 26, 2011, 01:32 PM
That is one really neat gun, I would love to have one. Reminds me of the FS2000.

November 26, 2011, 02:00 PM
Very cool. Talented fellow, this Aerostar. I found some old Chinese threads going back to 2005, where he intended to make a 'drop-in' chassis. You just drop your AR15 receiver into it, and go shooting. The current design uses it's own receiver and carrier design. The rails on the outside are from his 2005 project, adapted to the current design (actually, the rails are just a decorative shell over the top of his barreled action).

As opposed to the Aug and FS2000 designs, he moves the AR buffer and spring to the FRONT of the receiver, around the barrel, and links it to the bolt carrier (from which he removes the back half, since it's not needed to push the buffer into the AR buffer tube).

He has a lug on top of his carrier set up for gas piston operation, but I can't see where he installs the piston. Perhaps that's why he's just testing with a primed case rather than loaded ammo. He mentions that he has trouble getting it to work on live ammo.

November 26, 2011, 02:09 PM
Waiting on an ArchAngel kit for the RRA PDS or Para AR next. :evil:

November 26, 2011, 02:43 PM
im not a fan of making a weapon bull-pub. F2000,s, p90s, AUG's etc are great but leave the ARs and the AKs alone

451 Detonics
November 26, 2011, 03:52 PM
I would have to say I have a tough time calling setting off a single blank round a "success". You want a bullpup AR buy a Bushmaster...close enough...

November 26, 2011, 04:58 PM
I'm not a fan of bullpups but that looks pretty neat.

November 26, 2011, 08:40 PM
That is an interesting concept, but I think I'll stick to my M-17S...which looks to be pretty much what he's emulating to begin with (AR-15/18 bolt type + gas piston operation + bullpup configuration). I do wonder why on earth he would choose a long-stroke GP. :confused: That decision will probably have a negative impact on accuracy.


November 26, 2011, 08:59 PM
Success is a relative term.

November 27, 2011, 01:10 AM
Ooookay. So let me re-phrase this as "... succeeded relative to other attempts to bullpup an AR-15". Like the one listed here ( It's toward the end of the page titled "Ace AR Bullpup conversion".

If this goes into production, it would beat the M17S is that is appears to accept standard AR-15 barrels (see the second link on the first page), magazines, and it can eject from either the left or right side which prevents brass from flying in your face.

November 27, 2011, 10:42 AM
If this goes into production, it would beat the M17S is that is appears to accept standard AR-15 barrels (see the second link on the first page), magazines, and it can eject from either the left or right side which prevents brass from flying in your face.I seriously doubt it will beat the M17S where it counts...accuracy and reliability. From the looks of it, it won't be able to use unmodified AR barrels either, and the M17S already accepts standard AR-15 magazines of any type that I've tried (which is a long list). It's correct that you can't change the ejection pattern, but that's a minor issue IMO.


November 27, 2011, 12:49 PM
To echo the sediments of posters above, I like the ingenuity, but id pass on it as a gun id actually buy.

November 27, 2011, 01:16 PM
but leave the ARs and the AKs alone


November 27, 2011, 02:32 PM
Why?+1, new ideas is the stuff that breeds innovation and new designs. It doesn't matter if it works, or is a downright foolish idea, some good may come of it, so why not? I think there are enough ARs and AKs, and parts thereof, to cover one or two used in some crazy R&D experiment. I don't particularly care for it, but who knows the inventor may revise the design, or devise something entirely original, and come up with something revolutionary...for this reason I'm glad he's working on it. As unlikely as it is, he may become the next JMB.


November 27, 2011, 02:43 PM

Another Bullpup that ejects cases directly into my eye or ear. :banghead: That's great if you live in a dimension where everything moves right and the left side of cover deosn't exist. Ambi? Whuts that?

Have any of these guys witnessed the FN F2000, P90, or Keltec RFB ejection???

November 27, 2011, 03:10 PM
Have any of these guys witnessed the FN F2000, P90, or Keltec RFB ejection???IMO ambi-ejection, in the form that swaps the bolt & ejection port to the other side (after all you're either rt. or lt. handed so why is there a need to switch...particularly when you have to disassemble the rifle and use different parts?), isn't a big deal, but I have to admit the downward and forward ejection designs (like those mentioned) sure are nifty.


November 28, 2011, 11:43 PM

I did a quick search to make sure no one else posted this. It looks very well thought out and the ambidexrious issue is also addressed by a cheek piece that flips allowing the user to switch ejection from side to side without taking down the rifle.

Appearantly the inventor is a member of but I'm not a member there so I haven't looked for it.


November 29, 2011, 12:12 AM
Looks pretty neat but then again I love bullpups. I'd love to hear what the trigger weight is.

November 29, 2011, 11:41 AM
Same here. The barrel looks a little long, but he's still in the development stage anyway.

November 29, 2011, 02:23 PM
I love the way he fixed it for changing ejection direction.

December 15, 2011, 11:18 AM
I almost forgot I have an ID here.

If you guys prefer, and the board permit, I can repost what I did in ARFCOM.


Andrew Wyatt
December 15, 2011, 11:20 AM
That would be optimal.

December 15, 2011, 11:23 AM
and the board permit, I can repost what I did in ARFCOM.No problem. Go ahead.

December 15, 2011, 11:25 AM
OK, then here we go.

There are many questions asked there, but if you guys have any, please fire away. I will answer them as much as I can.


Not until the day before the Thanksgiving had I ironed out the legal content of my invention with my patent lawyer, such that the rifle I barely finished this summer is officially patent pending. Now it is time to show the world. Before anything, let me take this opportunity to thank everyone that helped me every step of the way to make this happen. And here you go...

First, a picture of me with the rifle.

The video you are going to see was shot on August 8th this year. Only one day before that, the Durocoat I sprayed on the rifle finally dry completely. The whole rifle is still kind of stiff. Some of the parts I make have screwed up tolerance, so you may notice some sluggish during the operation. Believe me, if I have had a little bit more time to polish that out, it should have been fine. That day is also scorching hot, 99F plus heat waves, so I have to use a shop fan to prevent dehydrate myself. So sorry about the noise. I have no choice. The very second day I have to leave the country, there is no time for me to shoot a better one.

I will continue to update or post more of the detail, but now let's start it with the video.

The reason prevent me go further is the bolt I made has excessive head space. I don't want to ruin my hard work for some uncertainties. A new bolt was almost finished before I leave the country. It is a shame that I couldn't get it done in time.

Just in case the audio is unbearable due to the noise, here is the transcripts of what's in the video.

My friends at XXX forum, as I promised, today I present you my first design, what I called "Longziz #1". As you can see, this is a bullpup rifle, which is capable to discharge the spent casing either from right or left without disassemble the gun. It is long stroke gas piston operated; it has a 20 inches barrel; I built it on top of an AR15 lower receiver, which is housed here (pointing to the stock). Now, I am going to demonstrate you how the direction of discharging the spent casing is converted. right now, the discharge is from the right. Let's see.(pulling the charging handle and released the bolt), one round in the camber; (racking the changing handle)discharge, (one round coming out of the right ejection port), (racking again) discharge, (another round coming out from right). and change to the left. just pull this lever, and flip the check piece. and now discharge from the left. (racking the gun and one round coming out of left port, rack again and second come out). Now if you want to change back, simply pull this lever again, and then flip the check piece. and it went back to discharge from the right. (rack the gun twice, two more rounds coming out of right port, and bolt holds). now you have it, longziz #1. Tell me what you thought. If you are not interested, if you are not impressed, which is OK. But stay tune for my Longziz #2.

December 15, 2011, 11:30 AM
I didn't manage to shoot real bullet in the range.

I did, however, fire a blank case with a fresh primer inside of my friend's "range"

Here is another video.

The whole idea started at the beginning of 2008. I was a Mechanical Engineering student in St. Louis, Missouri, facing graduation but holding no certainty of the future. The economic is not great, people around me were more or less killing time not thinking too much about it. I was more or less the same. Although I never consider myself a person the satisfying commonplaces, I wasn't clear where should I start then. Although I had long working experience before, but they were not related to the major I was studying. Even though I consider myself a good mechanical design engineer, I have no experience to back it up.

Playing firearm for many years, I start to develop the idea of doing something in this business. Firearm is considered as an amazing mechanical product in my mind. On the one hand, it is big enough to demand every aspect of mechanical engineering principles, yet small enough to be tackled by a single person. There are numerous forerunner in this business have done that, why not me? On September 2008, when I saw the wall street collapsed in front of my eyes in a single days, I know I need to do something.

Picking Bullpup as the subject to tackle was based on two factors. From a history point of view, this counter intuitive approach was having criticism starting at the day it was born. That is, you can only satisfy a left handed or right handed shooter, but not both. While right handed person are taking the majorities, left handed shooter found themselves distant from this kind fire arm. While the Chinese, Singapore, and Great Britain lefty soldiers are forced to fire their issued weapon with right hand, other counties, such as Israel, France and Austrian managed to make their military bullpup with ambidextrous design. However, to change the spent casing from right to left involves at least the disassemble of the gun, Tavor even needs its bolt to be replace to achieve that. So if I can design a bullpup rifle that allows the discharging switch while not needing disassemble the weapon, it would be a great improvement for this species. I had aware the existence of FN2000. However, discharging through the front is kinda new and not accepted by the main army forces, including its home countries army. Although it did find its home in many countries' special op forces.

The second reason is that, by then, I had purchased an AR15. The axial symmetric design of the AR bolt gave me an idea. If I can turn the bold head 135 degree, the direction of discharge can be achieved. The shape of the bolt head (together with the extractor head) is also like a straight tooth gear, if somehow I apply another mate-able gear to turn it, turning the bolt head is then possible. At the time, I have another AR15 lower with no use at the time, why not use it to build a bullpup? There are many AR part available in the market, going this way will lower the amount of machine work needed to complete a rifle. Isn't that great?

Since it is a bullpup, then the DI system must to go. Although there are many piston system or even revised DI system available in the market, since apparently I have do design a new bolt carrier, which is by no means a small scale project, why not design a new piston system of my own? When AR changed from DI to a piston system, the accuracy of the rifle suffers. This is almost considered as norm. If I design a piston which does the same or worse, why should I do it? So I set my aim to design a piston system that would maintain the DI accuracy, if not better.

Looking back, I consider myself was a dumb ass with first degree. If this is not shooting the moon, I don't know what is.

I had this idea at the beginning of 2008, started to play around with some CAD model in July and August, after September, I started the detail design for real. It took me about two month to finish the draft design, and it was almost Christmas time. In January I have to travel to Germany for three month. I married the woman of my life and she lives in Germany. I did try to convince her to come to the States, but been a poor foreign student with slim hope of find a good job in such a harsh economic environment, it is not hard to choose what was the best for the family. However, I couldn't give up my dream here just yet and hoping by doing this, I may achieve a better bargain to change my wife's mind. So even with only two weeks left, I decided to start manufacturing. Needless to say, I was way overestimate my capability of machining and way underestimate the challenge. If I knew what I know now, I probably wouldn't do it. However, the backside of the coin is, when people are cornered, it may inspired the inner energy that they themselves may not realize that it is there.

The bolt was naturally the most important part of this concept. So it is also the first to be manufactured, and soon I hit the first stone. Just before Christmas I ruin the only 3/32 mill bit I had in hand, only after milling out the first lug on the bolt. This is a must-have tool if I want to finish the rest seven lugs, but around Christmas, there is no way I can find a store that I can just walk in and pick it up. Online purchasing was the only way, but the delivery will last over the new year. So I start to make some parts that does not demand this drill bit. I did make some parts for the piston system. However, been a green mechanist, I just screwed up in every possible way. Judging from a few pictures I managed to took by then, I only made a few parts like gas block, piston, and some parts of the bolt assembly. The bolt head was made, but it was in such a bad quality it won't fit into the AR15 barrel extension just by looking at it.

I left the States on January 2009 with a broken heart, not only that I almost had nothing to show, I was also facing the challenge of finishing my dissertation paper in three month if I want to graduate in May. Before that I almost didn't write a word. Long story short, I wrote three paper in that three month. And together with other paper I published before, I managed to finished the dissertation paper before April, so a defense either by the end of April or early May was possible. In between all these academic obligation I had to stick with, I kept thinking what I did wrong in that two weeks. Looking back, that two weeks were not a total loss, simply because I screwed up every possible way. I was start too much in a hurry so a lot of things I didn't think straight before I did it. In those tiny biddy spare time between writing papers, I figured out the right sequence, tooling and setups that would help me have a clean run of manufacturing. So when I landed at Chicago ORD, I was pumped. I am going to get my goal. I am going to get my Doctor degree, and I am going to get the rifle done!

December 15, 2011, 11:32 AM
OK, too much story telling and too much texts. We need pictures!

This was the only two pictures I took during manufacturing period of the Christmas 2008. Believe it or not, the thing in the picture is the basic for the bolt head, with the firing pin hole just finished. The second is gas block, in 90% finished shape.

From now on the picture was taken between April 2009 to May 2009.

This is the 20 inch barrel before Christmas 2008. You can see it in the video, except this is before it is machined. I bought it cheap from an online retailer. When I first checked the barrel, I found the gas part bur was lodged inside of the barrel, and I couldn't push it out with a cleaning rod. I called to ask how I can deal with this. The guy said you can just shoot a round it will be out. I was skeptical but by then I was planning to work on it right away, so I didn't ask for a exchange. I shot two round out of it after I mounted it on my 7.62X39 AR15. It did DE-burred, just don't know if the barrel was scratched inside.

Billet used to make the upper receiver, 7075-T6 Aluminum. On Mcmaster it asks for $120, bought locally from Saperal (sorry if spell wrong) for just $40.

Some half done parts. Some of them didn't make it to the rifle you see. In it, there were piston, gas block, op rod interlink, upper receiver with barrel nut on it, and a locking ring to be the first one I discarded.

more picture.

Setting up to machine the barrel.

Start to turn down the profile. In my commercial design of the future (if I go that far at all), this is not necessary. I did this just for using the one AR15 A2 recoil spring I had in hand. Long story later.

Almost complete piston system.

You may notice the lathe I used in this picture is different from the one I used in previous two picture. There is a story behind it. The loathe I used in previous two picture belongs to my dear friend John. I also took my video shot in his garage. The lathe he has, compare to the lathe in my school, has better quality. This was why I do the barrel job in his shop. However, the shear pin that interlock the head with the cutter table was broken, so I can't cut thread on the barrel with his lathe. I don't trust the the lathe in my school to do the job (not a good judgement really), so I bought a die to cut the thread instead. This was one incident that showed I was an amateur. I didn't press the die before I turn it. It started with an angle and I didn't realize it until I couldn't turn it. The thread bite deep into the barrel and the thread cut looks like a snake. I thought this barrel is wasted.

My another friend Steve, who is also a friend of John, came to the rescue. He convinced me that any turning lathe is a good lathe and in terms of thread, as long as you have enough material left, it will do the job. We went to our school and I, under his instruction and supervision, got the correct thread back. Steve used to be a tool maker for McDonald Douglas and later Boeing. Like John and many other seasoned manufacturing expert, they lost their job due to various direct reasons, but nevertheless all accumulated to the fact that the manufacturing job in this country were shipped aboard. After several layoffs until 2006, Steve gave up his career as a tool and die maker, and find himself a prison cop job. He is still doing it today...


The piston system mounted on an standard AR15 for a firing test. The op rod was not made yet and won't able to be installed anyway. I was initially hoping to shoot a video to see if the piston would circle. Well, the home camcorder can't do ****. In the end, I did feel the gas blowing backward toward me, so at least the piston went out of the gas chamber.

Start to milling the upper receiver. The complex hole was contracted out to be done by EDM. This is the only machining that wasn't done by myself, and not counting the airline ticket fee, this is single most expensive investment of this project as well. And the result? Absolutely worth it!

Start to look familiar?

Start to mill the upper portion.

This is the third bolt head I've ever made, and it is the one in the rifle you see. Base on the lesson learned before, I manage to pull this one off without a glitch. It is pretty much finished based on look. However, there were still more work need to be done, the extractor slot, ejector hole, ejector retaining pin hole, extractor pin hole, etc, to name a few. Unfortunately, this is not going to be the one that do a real firing test. It has excessive head space and it is doomed even before I start to make it.

As I stated before, I only had a 7.62X39 AR, so I didn't buy a new 223 bolt to be the reference due to the stingy reason. I was a poor student and I have to use the money wisely. I borrowed a 223 bolt from a close friend. But I didn't ask and he didn't bother to tell me either, that his bolt was a second hand one. Even he didn't know, let along myself, that that bolt was already worn out. Plus the measurement error, the result is that the bolt had excessive head space on the drawing board. Later when I told my friend about this, he tell me something that was even more interesting. Not long after I returned this bolt back to him, the bolt was split in half during a range trip. Again, he didn't tell me (not that he has to). Costly lesson! There are more stories associate with this bolt and allow me to share with you later.

Now, the completed bolt with the bolt carrier assembly. The bolt is on a left discharge position. As you may notice, the bolt hadn't been heat treated yet. The triangle-ish shaped bolt carrier was not intentional. It was a weight relieve cut on the carrier. The mill was set on auto feed and my mind slipped for about several seconds.

Time was running out fast. The main purpose of the trip, to get my doctoral degree, was fulfilled. However, completing the gun was not. By then, I had an international meeting I scheduled to attend in, coincidentally, Germany. Before that date, I only managed to have completed about 75% of the upper, while the lower wasn't even started. This leave concluded my more than ten years stay in the United States. This also means my hope of finishing this project had to be suspended indefinitely. This is life, you don't always get what you want. On June 3rd 2009, on my way boarding the out bound airplane, I was thinking Arnold, "I will be back!"

December 15, 2011, 11:33 AM
Now, fast forward to June 2011.

I did come back. Two years past, more preparation and more design work done, I determined to finish the project this time, and more. To my gratefulness, all the help that I needed are still there, maybe even more so. I hit the shop very next day. I still had lots of screwed up along the way, but with lord's help, it went away one by one. I first managed to finished the upper, which is crucial for me to demo the function of changing sides.

This is the near completed upper receiver furniture. Can you find the charging handle? I utilized the CAD model I created for AR15 charging handle as the baseline of my design. It looked great on CAD, but when it was made for real, it was too small. But I didn't want to waste time on this just yet. If I had some cushion time later, I would remake one. Turned out to the right decision.

Remember I said the EDM was the only marching job I contracted out? That's true, but it is not the only job done by someone else. The sheet metal I used for the furniture skin was designed too thick that I can't bend it with a 12 foot break that my friend had in his shop. Thanks to the technician (sorry for forgetting his name) in a special lab, he helped me bent the metal, and he didn't charge me. It was actually made on 2009's trip. I didn't further machine on it much by then. Now the thing start to look like a bad ass.

Now start the lower part of the rifle.

This was the CAD model finished back in 2009. It was not the final version that you saw in the video, but it is pretty close. By then, I was thinking to mill this out of solid plastic, but changed my mind in the last minute due to the same stingy reason. I made the lower shell with fiber glass and aluminum hybrid. It was my first time mess with fiber glass so the finish really sucks. Nevertheless, it does the job. Here are the finish look before I paint it.

This proves that the rifle is related to AR15.

Now,here is the second part of the story, if not the legend, of the bolt.

The story happened before the lower part was made. Up till then, everything looked on the right track, and I was ready to assemble the upper all together to test the function of the discharging. When I first made the bolt and later heat treated in 2009, I was trying to install the ejector, extractor onto the bolt. I did it in the shop. As every AR15 DIY would experienced if they didn't study carefully of the sticky post in the DIY section of this forum, or not follow it thoroughly, would spring out the ejector at least once. If this happened in a nice clean room with carpet floor, it may only cost you several minutes and/or plus a few curse. However, if it happened in a machine shop that has piles of metal chips and cutoffs, you may wisely save a few minutes by just doing the cursing part, which I did. By then, I know I couldn't finished it and an ejector would be the last thing I would worry about. I left it without the ejector installed. The unfinished rifle, along with the bold, sit in my friend's safe for two years and maintained in a sparkle clean conditions. If you saw the pictures in previous post you may notice the barrel is Chrome Molly and after machining it looked like stainless steel. That actually is the natural color of Chrome Molly steel. I never did any surface treatment with it but it kept that shiny look without a single trace of rust. That fooled me big time.

When it was time to install a new purchased ejector in, I didn't bother to check the pocket hole. It is heat treated piece, from the outside, the dark oxidized surface is the right think to fight the rust. Little did I notice that inside that ejector hole, it is another situation. The ejector spring was put in with no problem telling. but when I push the ejector further in to insert the retaining pin, I realize something terribly wrong. The little bit rust on the wall seized the ejector and because for the installation of the retaining pin, it was pushed further inside that very little part of the ejector was exposed outside of the bolt face. All needle pliers that I can find had been tried with no luck. My friend tried heating and cooling method, WD40 overnight. No luck! The ejector was anchored there as if it was part of the bolt. So suddenly a promising track record was completely derailed.

I had no choice but to remake one. It supposed to be at least five day delay, that was the time I used to make the ****ed up one. The beginning of the remake was full of **** up also. I failed clamp the rough tight enough so it jumped and ruined. The second time when I drill the firing pin hole, the 90 degree drill bit seized inside the hole, what an oz! Later I have to cut the material out around the drill bit to save it. To my surprise, the HSS drill bit wasn't break. " You know what? God likes you." My friend John said that calmly when he saw the bit came out. It turned out to be true.

The third try was a charm. It turned out to be the best part I had ever made. It should be after all the lesson learned. This is how it looks. I spent three days to bring it to this stage and it is still like this when I am typing.

Right before I set up to mill the extractor pocket and on, I took the old bolt out for a final look, and I was stoned! Last time when I left it in a box after all the heat, cold and oiling, the ejector head was about flush with the bolt face. That day, I saw the ejector head came just a little bit above the bold face. Very slightly but noticeable. I immediate tried to slam it on the brick floor to let the momentum to drive it out, and guess what? After only five try, it came out! Later that day when John learned what happened, again he smiled and said calmly: "You know what? God likes you."

So, I lost three days out my time frame, but had a rescued bolt and a best made part that would not go into the file. Or so I thought...

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.

Cecil Sharps
December 16, 2011, 09:37 AM
I enjoyed reading the thread over on ar15, Hope you have some success with it.

Would you discuss your piston and recoil systemsl?


December 16, 2011, 03:07 PM
Well, as you can see, it is a annular piston system. so theoretically it will has less bending momentum acted on the barrel than other "on the top" system when firing. So I expect it will be more accurate than other piston systems.

However, that been said, the recoil is a very complex process and there are many other factors playing a role. As you may know already, the current piston system you see is a compromise of using a A2 recoil spring, so there's a lot of things need to be reconsidered before I can claim what I said above is true. So in that regard, it is still too soon to make any judgement. I do think it has a lot of potential though.

December 16, 2011, 03:24 PM
so are you any where near the taking orders stage? :D

December 16, 2011, 03:41 PM

Maybe a mod will combine the threads, better to track it that way.

December 16, 2011, 03:55 PM
<Your wish, my command --- merged!>

December 16, 2011, 04:03 PM
I think there is a long way I need to walk, if not crawl, through before I can confidently claim I am taking orders. However, whenever I heard someone saying that is like a kick on the butt for me to go further. :evil:

December 16, 2011, 07:24 PM
I cant wait for an OD model with maybe a 16 inch barrel :D would you sell it as a full rifle or start out with conversion kits to start?

December 16, 2011, 09:26 PM
thats awesome. one of my favorite new designs but i doubt it will go into production unless he kicks it to a major company

December 18, 2011, 02:07 AM
I had aware the existence of FN2000. However, discharging through the front is kinda new and not accepted by the main army forces, including its home countries army. Although it did find its home in many countries' special op forces.

Belgium Special forces use F2000s.

December 18, 2011, 12:00 PM
You are right, that's also why I said "Although it did find its home in many countries' special op forces. " :p

However, I just noticed that Croatia ordered FN2000 for their army, not just special force. So I guess I was wrong in some sense.:D

December 18, 2011, 12:38 PM
aerostar, as I mentioned before your design doesn't appeal to me much, but I applaud your tenacity and fortitude. I hope you are rewarded with success and push on to design other systems...perhaps one that suits my tastes a bit more.


December 18, 2011, 01:19 PM
Maverick223, thanks for your comment. I am not just looking for applause, but criticism as well, cause that will make me to design something better. So I appreciate your input.

To answer your question about long stroke. Well, not all long stroke are necessarily bad. AK's long stroke is good on reliability but sucks on accuracy due to its offset of the center of mass of the bolt carrier group and the barrel line. Mine are concentric. I need to use long stroke cause that I only need one set of spring to return the bolt carrier and the piston, and it also allow me to move the spring forward to allow shorter stock. I am yet to prove that mine will be as accurate as a DI system, so chances are I could fail and I also have a chance to achieve it. Until then, I am walking the walk.


BTW, what other system you are not satisfied with? So maybe I can make it a Longziz #8 or #9 or something. :D

December 18, 2011, 11:47 PM
I am not just looking for applause, but criticism as wellYou got it! :evil:

To answer your question about long stroke. Well, not all long stroke are necessarily bad. AK's long stroke is good on reliability but sucks on accuracy due to its offset of the center of mass of the bolt carrier group and the barrel line. Mine are concentric. I need to use long stroke cause that I only need one set of spring to return the bolt carrier and the piston, and it also allow me to move the spring forward to allow shorter stock. I am yet to prove that mine will be as accurate as a DI system, so chances are I could fail and I also have a chance to achieve it. Until then, I am walking the walk.I see. Keeping the mass in line with the bore will certainly be a improvement, but additional moving mass (harmonics) would seemingly be another concern (I don't profess to be an expert on the topic, just a thought to keep in mind).

BTW, what other system you are not satisfied with? So maybe I can make it a Longziz #8 or #9 or something.If it's a bullpup and a kit build (not a outright new design), it classifies as unsatisfactory (of course I haven't tried your design, so I can't rightfully lump it in with the others). To your credit, you have modified most of the original design so much that very little AR remains, whether that is good or bad has yet to be determined (I never much cared for the DI AR-15, so I don't consider it a detriment, but it does have quite a following).


December 19, 2011, 03:00 AM
That's actually very cool!

December 19, 2011, 03:41 AM
This is a really awesome and rare opportunity to see the trials an individual must go through in the development of a new weapon system. Thank you for sharing! I think you have a very succsessful career ahead of you.

December 19, 2011, 05:27 PM
Say what you want about bullpup rifles - but there is no denying that mans engineering skills!

I like your piston design much better than those currently on the market.

December 19, 2011, 07:39 PM
Part Kahn from King of the Hill
Part Eugene Stoner
All awesome.

December 19, 2011, 07:43 PM
... You DO realize he is participating in this thread right?

December 19, 2011, 08:22 PM
Thats Awesome!

December 19, 2011, 09:56 PM
Say what you want about bullpup rifles - but there is no denying that mans engineering skills!Who said anything about disliking bullpup rifles? Two of my favorite designs are bullpups and no less than four more (also not kits) are near the top of my list of things to purchase in the near future. I did, however, say that in my experience bullpup kit builds (I have tried several) leave quite a bit to be desired. I also prefaced that statement with something to the effect of: that was a blanket statement and without trying the aforementioned design that has yet to be determined. As far as engineering skills, that is a topic best left for the first test firing (I sincerely hope that all goes well, but anything before which time is bold speculation).


December 19, 2011, 10:30 PM
Truly excellent work.

December 19, 2011, 10:35 PM
Wow... thats one of the coolest conversions I have ever seen...

December 20, 2011, 12:30 AM
Guys, I appreciate all your kind words. As a former resident of the great 'show me' state, in term of evaluating myself, I actually agree with Marverick223. I claimed that I can do certain things, I bear the burden to prove it. Before I made this prototype, nobody believes me that it is achievable. Now one done, one more to go. My confidence is high. :evil:

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