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This is my first post and im no physicist so if this sounds stupid to you please explain to me why its dumb because I always like learning new things about gun design. Anyways ive had this idea in my head for a while now about a rifle concept and it first popped into my head when I was looking at the mechanics of a pkm. Like a lot of belt fed guns the piston is on the bottom of the barrel instead of the top and because the bolt and piston is so low it gives the pkm a good recoil impulse. My thought was how come no ones ever designed a rifle with the gas system below the barrel instead of on top? Imagine a SCAR but the barrel and the piston gas block is reversed.

This is one modern rifle that I'm insanely interested in, especially since there was a TFB article that hinted that there was a .308 Winchester/7.62mm NATO version being worked on that might use the same upper as the 5.56mm NATO version that HK has shown in several different versions since 2017. This is the latest (known) iteration of the 433, and if you've seen some of the POTD posts at TFB since May of last year, you've probably seen it a time or two. In short, the 433 is HK's answer to the FN SCAR and to try and one up it. IMO, the most interesting thing about the 433 is that it seems capable of taking way more caliber rounds than items such as the FN SCAR or the Bren 2, which needed new uppers in order to go rounds like .308. Out of curiosity one day, since I've seen numerous (though not often very new) photos of the 433 and I've also seen patent documents (I'll provide a link to patent documents and an article on Spartanat with some photos of the Gen 5 433), I decided to see if my own thoughts on the 433 being caliber convertible beyond .300 Blackout or 7.62x39mm held water. Using a simple image scaling and measuring program, I've determined that the 433 upper, as is, is capable of taking rounds or at least magazines of 71-72mm OAL. Mind you, this isn't exact, and I was conservative with my measurements. Of course, this does further peak my curiosity on what the 433 is capable of firing and how caliber convertible it may be. On top of of course how it comes apart and various details about it. Now the documentation. Spartanat is an Austrian site, and hence is in German, and being new here I'm not sure how Google translate works when linked, so I'll just leave the link (which has good, albeit sadly not ultra HQ/high res images, which IMO is a damn shame) to be copypasta'd into Google's translator or your favorite translator. On the plus side, there's a PDF in the article that you can save or convert to a pretty high res JPG or PNG image, and Google does a decent job of translating the PDF, too: https://www.spartanat.com/2019/05/photo-file-hk433-mit-concamo-im-feld/ Now here's the patent documents and images. This series mostly pertains to the charging handle system, but it shows a good idea of how the guts of the 433 are laid out: https://patents.google.com/patent/DE102018001984A1/en?inventor=Wilhelm+Fischbach

Here at Sturgeon's House, we do not shy from the wholesale slaughter of sacred cows. That is, of course, provided that they deserve to be slaughtered. The discipline of Military Science has, perhaps unavoidably, created a number of "paper tigers," weapons that are theoretically attractive, but really fail to work in reality. War is a dangerous sort of activity, so most of the discussion of it must, perforce, remain theoretical. Theory and reality will at some point inevitably diverge, and this creates some heartaches for some people. Terminal, in some cases, such as all those American bomber crews who could never complete a tour of duty over Fortress Europe because the pre-war planners had been completely convinced that the defensive armament of the bombers would be sufficient to see them through. In other cases though, the paper tiger is created post-facto, through the repetition of sloppy research without consulting the primary documents. One of the best examples of a paper tiger is the Tiger tank, a design which you would think was nearly invincible in combat from reading the modern hype of it, but in fact could be fairly easily seen off by 75mm armed Shermans, and occasionally killed by scout vehicles. Add to this chronic, never-solved reliability problems, outrageous production costs, and absurd maintenance demands (ten hours to change a single road wheel?), and you have a tank that really just wasn't very good. And so it is time to set the record straight on another historical design whose legend has outgrown its actual merit, the British EM-2: EM-2ology is a sadly under-developed field of study for gun nerds. There is no authoritative book on the history and design of this rifle. Yes, I am aware of the Collector's Grade book on the subject. I've actually read it and it isn't very good. It isn't very long, and it is quite poorly edited, among other sins devoting several pages to reproducing J.B.S. Haldane's essay On Being the Right Size in full. Why?!!?!! On top of that, there's quite a bit of misinformation that gets repeated as gospel. Hopefully, this thread can serve as a collection point for proper scholarship on this interesting, but bad design. Question One: Why do you say that the EM-2 was bad? Is it because you're an American, and you love trashing everything that comes out of Airstrip One? Why won't America love us? We gave you your language! PLEASE LOVE ME! I AM SO LONELY NOW THAT I TOLD THE ENTIRE REST OF EUROPE TO FUCK OFF. Answer: I'm saying the EM-2 was a bad design because it was a bad design. Same as British tanks, really. You lot design decent airplanes, but please leave the tanks, rifles and dentistry to the global superpower across the pond that owns you body and soul. Oh, and leave cars to the Japanese. To be honest, Americans can't do those right either. No, I'm not going to launch into some stupid tirade about how all bullpup assault rifle designs are inherently a poor idea. I would agree with the statement that all such designs have so far been poorly executed, but frankly, very few assault rifles that aren't the AR-15 or AK are worth a damn, so that's hardly surprising. In fact, the length savings that a bullpup design provides are very attractive provided that the designer takes the ergonomic challenges into consideration (and this the EM-2 designers did, with some unique solutions). Actually, there were two problems with the EM-2, and neither had anything to do with being a bullpup. The first problem is that it didn't fucking work, and the second problem is that there was absolutely no way the EM-2 could have been mass-produced without completely re-thinking the design. See this test record for exhaustive documentation of the fact that the EM-2 did not work. Points of note: -In less than ten thousand rounds the headspace of two of the EM-2s increased by .009 and .012 inches. That is an order of magnitude larger than what is usually considered safe tolerances for headspace. -The EM-2 was less reliable than an M1 Garand. Note that, contrary to popular assertion, the EM-2 was not particularly reliable in dust. It was just less unreliable in dust than the other two designs, and that all three were less reliable than an M1 Garand. -The EM-2 was shockingly inaccurate with the ammunition provided and shot 14 MOA at 100 yards. Seriously, look it up, that's what the test says. There are clapped-out AKs buried for years in the Laotian jungle that shoot better than that. -The EM-2 had more parts breakages than any other rifle tested. -The EM-2 had more parts than any other rifle tested. -The fact that the EM-2 had a high bolt carrier velocity and problems with light primer strikes in full auto suggests it was suffering from bolt carrier bounce. As for the gun being completely un-suited to mass production, watch this video: Question Two: But the EM-2 could have been developed into a good weapon system if the meanie-head Yanks hadn't insisted on the 7.62x51mm cartridge, which was too large and powerful for the EM-2 to handle! Anyone who repeats this one is ignorant of how bolt thrust works, and has done zero research on the EM-2. In other words, anyone who says this is stupid and should feel bad for being stupid. The maximum force exerted on the bolt of a firearm is the peak pressure multiplied by the interior area of the cartridge case. You know, like you'd expect given the dimensional identities of force, area and pressure, if you were the sort of person who could do basic dimensional analysis, i.e. not a stupid one. Later version of the British 7mm cartridge had the same case head diameter as the 7.62x51mm NATO, so converting the design to fire the larger ammunition was not only possible but was actually done. In fact, most the EM-2s made were in 7.62x51mm. It was even possible to chamber the EM-2 in .30-06. I'm not going to say that this was because the basic action was strong enough to handle the 7x43mm, and therefore also strong enough to handle the 7.62x51mm NATO, because the headspace problems encountered in the 1950 test show that it really wasn't up to snuff with the weaker ammunition. But I think it's fair to say that the EM-2 was roughly equally as capable of bashing itself to pieces in 7mm, 7.62 NATO or .30-06 flavor. Question Three: You're being mean and intentionally provocative. Didn't you say that there were some good things about the design? I did imply that there were some good aspects of the design, but I was lying. Actually, there's only one good idea in the entire design. But it's a really good idea, and I'm actually surprised that nobody has copied it. If you look at the patent, you can see that the magazine catch is extremely complicated. However, per the US Army test report the magazine and magazine catch design were robust and reliable. What makes the EM-2 special is how the bolt behaves during a reload. Like many rifles, the EM-2 has a tab on the magazine follower that pushes up the bolt catch in the receiver. This locks the bolt open after the last shot, which helps to inform the soldier that the rifle is empty. This part is nothing special; AR-15s, SKSs, FALs and many other rifles do this. What is special is what happens when a fresh magazine is inserted. There is an additional lever in each magazine that is pushed by the magazine follower when the follower is in the top position of the magazine. This lever will trip the bolt catch of the rifle provided that the follower is not in the top position; i.e. if the magazine has any ammunition in it. This means that the reload drill for an EM-2 is to fire the rifle until it is empty and the bolt locks back, then pull out the empty magazine, and put in a fresh one. That's it; no fussing with the charging handle, no hitting a bolt release. When the first magazine runs empty the bolt gets locked open, and as soon as a loaded one is inserted the bolt closes itself again. This is a very good solution to the problem of fast reloads in a bullpup (or any other firearm). It's so clever that I'm actually surprised that nobody has copied it. Question Four: But what about the intermediate cartridge the EM-2 fired? Doesn't that represent a lost opportunity vis a vis the too powerful 7.62 NATO? Sort of, but not really. The 7mm ammunition the EM-2 fired went through several iterations, becoming increasingly powerful. The earliest versions of the 7mm ammunition had similar ballistics to Soviet 7.62x39mm, while the last versions were only a hair less powerful than 7.62x51mm NATO. As for the 7mm ammunition having some optimum balance between weight, recoil and trajectory, I'm skeptical. The bullets the 7mm cartridges used were not particularly aerodynamic, so while they enjoyed good sectional density and (in the earlier stages) moderate recoil, it's not like they were getting everything they could have out of the design. note the flat base In addition, the .280 ammunition was miserably inaccurate. Check the US rifle tests; the .280 chambered proto-FAL couldn't hit anything either.

So after doing some sluething on my state laws, I discovered some pretty major loopholes in handgun ownership for those under 21 (I’m 19) From what I’ve gathered and from what I’ve been told by those I know in law enforcement and those currently serving in the military, I can legally own a handgun and actually carry the handgun in my vehicle even though I’m not 21 due to some loopholes in handgun and firearm ownership laws. What would be a good starter handgun to buy as my first handgun? I would like to buy one now and then get my CCW and use that handgun for when I’m legally allowed to carry it on my person. I personally wouldn’t mind carrying SOME full sized handguns like a Glock 17 or M&P 2.0 Also what would be a good starter AR to get that’s below $1,000; that’s another firearm on my list to soon get.

This post is probably going to be a bit ramble-y, but bear with me as I get to the point. It has become apparent to me, over time, that the United States has something of a strange pathology regarding violence and authority. With the recent racially-tinged unrest in Ferguson, I thought it might be time to both chat about this and offer a concrete, material, all-American solution to the problem. Firstly, there seems to be a strange (and, from what I hear, common) misunderstanding in the US and some other places about the role, effect and legitimacy of violence in bringing about social change. All too often, there seems to be an implicit understanding that protest can only be legitimate if it is non violent - with any incidence of violence during a protest being used to tar that movement generally. This, combined with a frankly disturbing cult of worship centred around law enforcement officers and members of the armed forces, results in 'seen but not heard' syndrome. The way this works is pretty interesting: if a movement uses non-violent means to protest, then it gets ignored and beaten up by the cops (who are, by virtue of their magical status in society immune from substantial criticism for doing so). If it uses violence, then the cops suddenly play nice while the media takes on the task of delegitimising the movement. Finally, if no protest occurs then nobody notices. There are, so far as I can see, only a few ways out of this trap: Be white, upper-class and non-violent. Push your agenda through using the existing state apparatus and a friendly media (who will treat a rich and pretty white woman with kid gloves 99% of the time and a handsome, well-spoken white man damn near 100%) Be white, of any class and violent. Rely on the fact that the target of your violence isn't on the right side of the media divide and that you can use existing state apparatus to push your agenda from within. Be non-white and form a massive coalition with prominent white backers and supporters. Be aware that any non-white leaders/figureheads will have their lives scrutinised ruthlessly and thus need to be saints. Also be ready to have said leaders/figureheads posthumously canonised by the very same people who would happily feed them to the dogs in the present. The above is, of course, intentionally provocative. However, what is indisputable is the fact that no movement that doesn't already have the nation substantially on its side (in as far as that phrase includes such diverse things as existing biases in media, power dynamics and politics) can achieve much in the way of change in the US if it is peaceful or directly violent. As a consequence, any movement should look to the careful cultivation of the media, a strong and continual attempt to use existing state structures to further your agenda and the ability to credibly threaten violence if it wishes to succeed. Central to all of this is to have very strong discipline and control - something which is especially hard in a surveillance state such as the US. Here is where I (finally) get to the reason why this post is in this forum. What the libertarians get right (even if it is damn near the only thing) is that being well armed suddenly makes people take you seriously. Unfortunately, the people who need to be taken seriously tend not to be well armed: weapons are expensive and weapon controls tend to push down on the undesirables more than the privileged. What people who want to affect change in their societies need, then, is a way to arm significant numbers of their members in ways that are both credible and cheap. For this (overly) simplistic solution to an intricate problem, I am going to ask my fellow forumites to do two things: 1) Debate the use of violence as part of a legitimate strategy of social change in a paradoxically docile and reasoned way, and 2) Design a weapon that can be made simply and very cheaply to provide our would-be protesters the means to march in peace while the cops stand far, far away. Having had a bash at number 1), here is my bid for number 2): For the US - with its easy access to ammunition, parts and machinery - it might be best to design a rifle of some sort. My pet solution here is an intermediate calibre weapon using a gas-delayed blowback action (basically a straight blowback with a gas tube venting to the rear of a very heavy bolt) and firing from a closed bolt. People who know more about gun design than me (a low bar to clear if ever there was one) can feel free to propose something less idiotic. Have at it, gents.

At the end of January, 2018 and after many false starts, the Russian military formally announced the limited adoption of the AEK-971 and AEK-973 rifles. These rifles feature an unusual counterbalanced breech mechanism which is intended to improve handling, especially during full auto fire. While exotic outside of Russia, these counter-balanced rifles are not at all new. In fact, the 2018 adoption of the AEK-971 represents the first success of a rifle concept that has been around for a some time. Earliest Origins Animated diagram of the AK-107/108 Balanced action recoil systems (BARS) work by accelerating a mass in the opposite direction of the bolt carrier. The countermass is of similar mass to the bolt carrier and synchronized to move in the opposite direction by a rack and pinion. This cancels out some, but not all of the impulses associated with self-loading actions. But more on that later. Long before Soviet small arms engineers began experimenting with BARS, a number of production weapons featured synchronized masses moving in opposite directions. Generally speaking, any stabilization that these actions provided was an incidental benefit. Rather, these designs were either attempts to get around patents, or very early developments in the history of autoloading weapons when the design best practices had not been standardized yet. These designs featured a forward-moving gas trap that, of necessity, needed its motion converted into rearward motion by either a lever or rack and pinion. The French St. Etienne Machine Gun The Danish Bang rifle At around the same time, inventors started toying with the idea of using synchronized counter-masses deliberately to cancel out recoil impulses. The earliest patent for such a design comes from 1908 from obscure firearms designer Ludwig Mertens: More information on these early developments is in this article on the matter by Max Popenker. Soviet designers began investigating the BARS concept in earnest in the early 1970s. This is worth noting; these early BARS rifles were actually trialed against the AK-74. The AL-7 rifle, a BARS rifle from the early 1970s The Soviet military chose the more mechanically orthodox AK-74 as a stopgap measure in order to get a small-caliber, high-velocity rifle to the front lines as quickly as possible. Of course, the thing about stopgap weapons is that they always end up hanging around longer than intended, and forty four years later Russian troops are still equipped with the AK-74. A small number of submachine gun prototypes with a BARS-like system were trialed, but not mass-produced. The gas operated action of a rifle can be balanced with a fairly small synchronizer rack and pinion, but the blowback action of a submachine gun requires a fairly large and massive synchronizer gear or lever. This is because in a gas operated rifle a second gas piston can be attached to the countermass, thereby unloading the synchronizer gear. There are three BARS designs of note from Russia: AK-107/AK-108 The AK-107 and AK-108 are BARS rifles in 5.45x39mm and 5.56x45mm respectively. These rifles are products of the Kalashnikov design bureau and Izmash factory, now Kalashnikov Concern. Internally they are very similar to an AK, only with the countermass and synchronizer unit situated above the bolt carrier group. Close up of synchronizer and dual return spring assemblies This is configuration is almost identical to the AL-7 design of the early 1970s. Like the more conventional AK-100 series, the AK-107/AK-108 were offered for export during the late 1990s and early 2000s, but they failed to attract any customers. The furniture is very similar to the AK-100 series, and indeed the only obvious external difference is the long tube protruding from the gas block and bridging the gap to the front sight. The AK-107 has re-emerged recently as the Saiga 107, a rifle clearly intended for competitive shooting events like 3-gun. AEK-971 The rival Kovrov design bureau was only slightly behind the Kalashnikov design bureau in exploring the BARS concept. Their earliest prototype featuring the system, the SA-006 (also transliterated as CA-006) also dates from the early 1970s. Chief designer Sergey Koksharov refined this design into the AEK-971. The chief refinement of his design over the first-generation balanced action prototypes from the early 1970s is that the countermass sits inside the bolt carrier, rather than being stacked on top of it. This is a more compact installation of the mechanism, but otherwise accomplishes the same thing. Moving parts group of the AEK-971 The early AEK-971 had a triangular metal buttstock and a Kalashnikov-style safety lever on the right side of the rifle. In this guise the rifle competed unsuccessfully with Nikonov's AN-94 design in the Abakan competition. Considering that a relative handful of AN-94s were ever produced, this was perhaps not a terrible loss for the Kovrov design bureau. After the end of the Soviet Union, the AEK-971 design was picked up by the Degtyarev factory, itself a division of the state-owned Rostec. The Degtyarev factory would unsuccessfully try to make sales of the weapon for the next twenty four years. In the meantime, they made some small refinements to the rifle. The Kalashnikov-style safety lever was deleted and replaced with a thumb safety on the left side of the receiver. Later on the Degtyarev factory caught HK fever, and a very HK-esque sliding metal stock was added in addition to a very HK-esque rear sight. The thumb safety lever was also made ambidextrous. The handguard was changed a few times. Still, reception to the rifle was lukewarm. The 2018 announcement that the rifle would be procured in limited numbers alongside more conventional AK rifles is not exactly a coup. The numbers bought are likely to be very low. A 5.56mm AEK-972 and 7.62x39mm AEK-973 also exist. The newest version of the rifle has been referred to as A-545. AKB and AKB-1 AKB-1 AKB AKB, closeup of the receiver The AKB and AKB-1 are a pair of painfully obscure designs designed by Viktor Kalashnikov, Mikhail Kalashnikov's son. The later AKB-1 is the more conservative of the two, while the AKB is quite wild. Both rifles use a more or less conventional AK type bolt carrier, but the AKB uses the barrel as the countermass. That's right; the entire barrel shoots forward while the bolt carrier moves back! This unusual arrangement also allowed for an extremely high cyclic rate of fire; 2000RPM. Later on a burst limiter and rate of fire limiter were added. The rifle would fire at the full 2000 RPM for two round bursts, but a mere 1000 RPM for full auto. The AKB-1 was a far more conventional design, but it still had a BARS. In this design the countermass was nested inside the main bolt carrier, similar to the AEK-971. Not a great deal of information is available about these rifles, but @Hrachya H wrote an article on them which can be read here.

As a current side project stops and starts according to my whims, I figured I might as well create here and keep updated a list of rules/guidelines for design of lightweight automatic/autoloading rifles and other weapons. Here's what I have so far: 1. Volume is mass; smaller means lighter. 2. The lightest, strongest shape is the sphere, and it has the least surface area for its volume. Cubes, though conceptually simple, should be avoided where possible. All light weapons desire to approach the shape of the cylinder, an elongate sphere. 3. (For conventional-layout weapons) Adding one ounce of weight in front of the point of balance adds two in total. 4. The primary mass is the primary driver of the total system mass. As a rule of thumb, adding 1 gram to the bolt mass adds 10 grams total to the rifle. 5. The only way to achieve exceptional lightness of weight is to reduce weight wherever possible, no matter how minor the savings in each case. The best way to lighten a rifle by 10% is not by cutting the weight of one component dramatically, but by reducing the weight of all components by 10%.