This is a prototype accessory I made for AR15 rifle, and it is the second prototype I made related to AR15. The Longziz #1 story can be found here.

First of all, thanks to mod DPMMN for your support.

It's been a week since I started the post and it seems to me that whoever figured out what the Longziz #2 really is didn't actually speak out. So let's cut the chase and reveal what the Longziz #2 really is.

The 7.62X39 has the most tapering casing among all AR calibers. If Longziz #2 can handle it with ease, theoretically it has the capability to handle any casing that its casing tapering is smaller than the 7.62X39. The #2 in this current configuration should be also feed 6.8SPC and 6.5 Grendel reliably without any changes. However, with my patent pending self adjustable mag shell design, the completed Longziz #2 is a universal magazine that can feed ALL AR15 double stackable, conter firing, rifle cartridges reliably.

I know, I don't have a video to prove that just yet. In last summer, I run out of time and production means so I didn't make the mag shell. However, if you have seen what I have shown, do you have the confidence to believe that what I said may very likely to be true?

My lawyer managed to file the patent application before the USPO close for the year. So it is ready to be shown to the public, and here you go for the video.

Longziz #2

For those who are expecting Longziz #2 as another firearm, sorry if this disappointed you. Longziz #1 took almost three years to be finished manufacturing, while longziz #2 only took 2 days.  So it is not hard to accept that #2 is just an accessory.

However, in terms the sequence the concept came into my mind, Longziz #2 is way earlier than Longziz #1. As you may know, the first AR I have ever bought is 7.62X39 caliber, and it was in the year 2006. The reason I didn’t buy the 223 caliber is simple, my first rifle was a SKS and I don’t have any other rifle in 223 caliber. To simplify ammo storage, I choose the 7.62X39 caliber instead. When I bought the rifle, I know the high capacity magazine is hard to find. A friend of mine also has AR in this caliber and he managed to collect almost all possible magazine for this caliber. However, none of them work flawlessly.  By then, the Cproduct LLC was claiming developing 30 rounds magazine for this caliber. However, that claim lasted for more than two years. While waiting, I bought two Cproduct magazines, one in 6.5 Grendel caliber and one in 6.8 SPC caliber. One is with a blue follower and the other is with a black follower. They are not made for M43 rounds so I experienced a lot of jam when used on my 7.62X39 AR15. While waiting impatiently for the dedicated M43 magazine to come, my mind started to work in gear of what I can do to ease the frustration.

The idea is very simple. The M43 round will introduce far more tilt inside of the STANAG magazine comparing to other calibers. If a non-tilt follower is used, the rounds can have a nose dive if certain amount (very small) of ammo is inserted, hence more prone to induce jam. If a tilt-able follower is used, the follower tend to tilt too much if a large amount of ammo is inserted, such that the follower would slide into the gap between the round tips and the front magazine wall and cause the ammo tail sink into the cavity the follower left behind, which also introduce jam. So I thought, maybe I can use a two piece follower approach, one that is non tilt, while the other is tilt-able. This way, the follower assembly would be stable inside of the magazine, while the tilt-able piece to accommodate tilt introduced by the ammo.

I can’t remember exactly why I didn’t prototype this idea by then. Maybe it was only in 2006 and I had not felt the pressure of graduation yet. Or perhaps because I thought it was too expensive to make a prototype since all magazine followers are made by injection molding. Or partly because I thought that Cproduct will have the M43 magazine out soon so my design may have no use.

In the end, it took Cproduct more than two years starting from the first time they claimed to have the magazine out in a few weeks. By then, it is already 2008 (if I remember correctly), and I have already known that I was going to move to Germany, so that magazine did not mean much anymore, since I have to get rid of the AR.  Besides, I had started the Longziz #1 project, so the follower idea was put into my back shelf, until I came back to the States to finish Longziz #1 for the last time. After all, I found out that after five years since the Cproduct had started to make the magazine for this caliber, we are still in the situation of not having the right magazine for this caliber. And I can’t believe that no one else have come up a similar idea to address this. And for the two years that I was living in Germany, I have time to develop the idea even further. However, longziz #1 was still the priority, until now.

I like it!  Definitely looks better than the agressively curved CP 7.62x39 mag

Range Report

Tagged for next year.

Well if you do come out with this and the followers are reasonably priced I would imagine you'd have a pretty big market for these... I know I would pick up a couple dozen

Fred R.

Dude, your designs are on to something. Keep being creative and 2012 is going to be a rewarding year for you.

I like it.  The only problem I see is that chainsaw is leaking bar oil all over your cement.

tag

Guys, I need you help on testing Longziz #2.

Whoever lives in Chicago area, that either have an 6.8SPC upper and/or 6.5 Grendel upper, and willing to help, please contact me. I will ask a friend of mine to meet with you to use Longziz #2 on your rifle, to see if it can feed those caliber efficiently without any problems. Your help will be highly appreciated, and you are welcome to ask for return. Thanks!

Again, happy new year!

Tagged for interest as a 7.62x39 AR owner who would deperately like a 20-something capacity mag.

You are doing some Great Work my friend.  Thanks for sharing.  It lets us know that there are still some people with some new ideas that will make our sport even more fun.  Best wishes in 2012 and may God bless!

Impressive to say the least.  Very excited to see what's next.

One more range report video.



My friend John (no, the other John) shooting AR with Longziz #2

Longziz,

I have always stayed away from the 7.62x39 uppers because of the magazines. Your take on the situation is as innovative as your other project (#1).

It is great to see such a breath of fresh air in the firearms community - I wish you much success!

Tag for updates.

It's been a week since I started the post and it seems to me that whoever figured out what the Longziz #2 really is didn't actually speak out. So let's cut the chase and reveal what the Longziz #2 really is.

The 7.62X39 has the most tapering casing among all AR calibers. If Longziz #2 can handle it with ease, theoretically it has the capability to handle any casing that its casing tapering is smaller than the 7.62X39. The #2 in this current configuration should be also feed 6.8SPC and 6.5 Grendel reliably without any changes. However, with my patent pending self adjustable mag shell design, the completed Longziz #2 is a universal magazine that can feed ALL AR15 double stack-able, center firing, rifle cartridges reliably.

I know, I don't have a video to prove that just yet. In last summer, I run out of time and production means so I didn't make the mag shell. However, if you have seen what I have shown, do you have the confidence to believe that what I said may very likely to be true?

goodness, that is interesting.

Very interesting.

What would the capacity be for a .223/5.56 case?  30?

Is this going to be just a follower that can be used with STANAG mags? If so that would be great for ban staters.

Very cool.  Keep up the good work.  I'm in the Chicago area, but unfortunately do not have the 6.8 or 6.5 calibers you need tested  

I have a 6.5 g.  Send it to me and I'll test it for ya.

usmc0331tamu00, thank you very much for your offer, you are so kind. However, no offense, but I am not sending out the prototype for test. A face to face range time with my friend is the only way I am looking for. Since the time is really limited, I am not pushing it anymore. As one of the member suggest, I may buy a 6.8 and 6.5 upper myself. It's a good excuse to enter into this caliber now.

Don't blame you- I wouldn't either.  My offer was really tongue-in-cheek.  

Just out of curiosity ...... have you tried this out with rimmed cartridges?  If your follower would allow the reliable feeding of rimmed cartridges out of AR (and other) mags, you will have changed the firearms world.

Futuremodel, you just raised the bar, as an engineer I always like to take on challenges. The reason I exclude rim caliber is the only rim caliber upper I know is 22LR. It is simply too short and too small to stack orderly in the mag. Name the rim caliber you are interested in, I at least can simulate it on CAD to see if there is a possibility.

I'm about to build my 7.62 x 39 ar, and i would give almost anything for a few mags that worked, but weren't so long and goofy looking as the asc/cproducts. I'm not concerned with having more than 20 rounds, so this follower would be perfect!

For AR style mags I'd start with the most popular rimmed pistol rounds like 357 mag, maybe 327 mag, then move on to 454 Casull and 44 mag. Some like the 480 Ruger also fit, but are probably too obscure to waste time one. 460 S&W (at 2.29") and 500 S&W (at 2.25") would be awesome but may be too long to fit reliably.



Most rimmed rifle cartridges are too long for AR mags with the exception of 30 carbine, but many would fit in a AR308 mag (30-30, 45-70) if you take it to that next step.

My thoughts are that the old less curved Colt 7.62x39 "30 round" mags ...... that in reality could only take 5 or 6 rounds before *jamming up in the mag ......... would be ideal for a 20-ish round 7.62x39 AR mag.



*ETA:  I should state it as "binding" rather than "jamming", just to keep the nomenclature concise.

futuremodal, no offense, but AR does not make those caliber upper. I think it is pointless to do a mag for those caliber. If you are talking other firearms, then it is different story.

BTW, rim ammo need some clearance on the barrel to allow the extractor to catch the rim. On current AR barrel configuration, I don't think it is feasible to have a rim caliber AR upper. 22LR is using chamber insert plus blow back mechanism, so that is a totally different story.

There are .357 and .44 magnum AR15s out there. Pretty sure they use desert eagle magazines. Obviously they are something that must be custom made. Ronald Williams is working on the .357 and I think Tromix used to offer the .44 magnum.

Ah, just realized that these are pistol caliber. well, then this is another story. As I said, my current design only deal with rifle cartridge. But, this might be a good challenge if the demand is high.

There are already AR barrels made in .310 for the 7.62x39 so a barrel in .312 isn't that far off the mark. Plenty of pistol caliber AR barrels in .357 and .45, just need to ream the chamber to the new specifications.



One reason this would be a huge market is for when people go out in the backcountry where you want a large bore revolver as a sidearm against bears and such, you can have your sidearm and your AR using the same cartridge type.   Especially if you can use stardard AR mags with these new fangled followers.

Do you see these followers working with 5.45 cartridges in standard AR mags?

ETA: Specifically, only about 75% of my C-product 5.45 mags cycle reliably. Of those that work, they only hold the last round open maybe half the time. I've modified followers on Pmags to work with 5.45 but can only load to 25 rounds without malfunction.

If your follower feeds 30 rounds of 5.45 and operates the bolt hold open reliably, I think you'll do well.

Yeh, I noticed that I made a mistake by assuming these are for rifle caliber, while in fact they are pistol caliber. When you say rimed ammo for AR, I was thinking something like 30 Herrett. Since they are shorter than usual rifle calibers, so space wise it is possible with a modified mag shell. with a plug in the front or something. However, how to stack then in double stack fashion is kind a challenge. Can you or someone else tell me is there an existing mag that double stack rim cartridge? Does desert eagle mag double stack or just single stack? Never saw one myself.

I just did some quick calculation, both of the 357 mag and 44 mag have equivalent case tapering (because of the rim) larger than the 7.62X39. So theoretically my current follower would only handle around 20 round, give or take. 44 mag has bigger rim diameter than the 7.62X39, so for this one may be even a little bit lesser.  Would this be too few?

this is what I was wondering about but the mag issue has kept me from getting into 7.62x39 also

Tagged 4 later

I just assumed the DE mags were single stack.  I know .22lr AR mags are single stack as well as the .410 AR mags from Safir.  This is one reason I envisioned sticking to the larger bores like 454 - the 450 Bushmaster is sort of an offset single stack.  357 would probably end up being sort of offset single stack, not straight line single stack nor true double stack.  I think the 327 mag would probably double stack okay since it's rim is a bit less obtuse than the others.  



Hopefully someone will clarify this assumption on my part.

Interesting idea.  Standard mag body shape with an insert having a wider back than front would allow the rear of the cartridges to slightly stagger, and the front would be perfectly aligned.  That would allow a lesser curve, one that could match the 7.62 body curve.

Well, I just figured another problem with rimmed ammo in AR. For auto loader firearm, the ammo has to allow the bolt and bolt carrier group to pass on top of them to allow feed. For AR, there is a gap between the end of the bolt head and the front face of the bolt carrier. When the bolt carrier cleared the rim, the ammo will be pushed out and the rim will occupy the space between the bolt and the bolt carrier, when the bolt carrier moves backward. This will cause a problem, cause the bolt head will catch up with the rim. Although the momentum of the bolt carrier group may clear the bolt over the rim and pass it, it also may throw the first round out of the mag as well. In bolt action rifle or a blow back rifle, this is not a issue cause there is no bolt carrier and the bolt is continuous. I will draw a picture if my text above is hard to understand.

That's a good point.  What would need to happen is a way to rotate the bolt on the back movement in a way where the lugs won't catch the rim, maybe have to eliminate one of the lugs (like this? ^ ), then on the forward movement rotate one of the lugs straight down to catch the next round.  That might end up being more R&D work than is worth it since it might mean a complete boltface/bolt carrier redesign.



On a related subject, I just read up on the new Coonan Arms .357 1911-type pistol.  The gun uses a more staggered single-stack in the mag, and I'm betting the bolt uses the same type of rotation I described above to avoid the problem you brought up.



http://www.gunsamerica.com/blog/coonan-arms-classic-357-magnum-1911-pistol/

For 1911 type hand gun there is no issue with rimmed ammo, cause the slide (bolt) is one piece. The barrel is moveable for the ease of feeding and locking.

Longziz, your theory about the pistol cartridges would be true in the case of a bolt with locking lugs. The Olympic Arms pistol caliber uppers use a cone shaped bolt and are blowback operated. I feel that it would work in this regard.

My lever action .357 pushes factory 158 grain bullets about 1600 fps and I can load it much hotter. If I could up my magazine capacity it would make it a hell of a short range blasting stick.

Tag

I have an Oly 9mm upper and the bolt is as you describe.  Thing is, I believe a 357 mag, or even a 327 mag could probably use a DI system.



One other thing I forgot to mention regarding rimmed cartridges in AR's - the Safir .410 upper uses a rotating bolt that has an ejector lug, a holding lug opposite the ejector, and bottom lug.  When rotating back the bottom lug is off to the side so it doesn't catch the rim, then as the bolt returns forward the bottom lug is rotated back to the bottom to catch the next round.  Seems the same could work for other rimmed cartridges.

on all these little wildcat ammo things you have to wonder just how big the market really is.  You are outside the u.s. so you can tool in China, use cracked CAD and do whatever you want as ITAR is a one way door that doesn't care about things coming in.  But it still is going to be expensive even in China if you did the whole magazine.  If you are just making a follower, hell even in the U.S. an injection molded follower like the magpul follower is only 20K.  

If your design is accomodating to taper I would say it is the exact opposite of what half these people judge as a good magazine-anti-tilt.  The lips are long enough that you just need the follower pushing to match the math addition of taper angles and you could do this by spring pivot shifts, really tilting follower with spring bias, a bunch of different ways to have the rounds level at lips and let the follower decide its own push angle.  

Glad to see you use your brain, the world of arms has just been flat out abandoned with true ingenuity and replaced with advertising and buzz words that people just use to argue over the internet with.

Sorry, Just realized that I overlooked your question. I haven't done any test neither made a prototype follower to suit with a standard AR mags. However, theoretically the 5.45 has a smaller tapering case than that of the 7.62X39, so it should feat. However, please allow me to remind you that the rim diameter of 556 is 9.6mm and the 5.45 is 10mm. Don't underestimate the .4mm difference. That may translate to less round of 5.45 in a standard AR mags. However, 25 rounds seems to be fewer than I thought. My guess is it should be able to handle 27 or 28.  

So when can we get our hands on these magazines??!!?! I have a 7.62x39 that runs 100% reliable with ASC Magazines, but if the Longziz follower is real, I'm all over it...

How about people quit worrying about other random loads and lets get the 7.62x39 into production first. Once he's revolutionized the industry, then we can worry about pistol rounds.

What's the status on this? I really want a 7.62, but this is kind of what I'm waiting for.