BarnOwlLover

I'm just explaining what I've been told by others elsewhere. I'm ready and willing to learn as well. However, if that's not desired here, I'm ready and willing to leave. I've read the forum rules and requests, and I'm doing the best I can with what I know. If that's not good enough, all you have to do say please go pound sand.

The thing that has to be remembered is that the SCAR was broken up into the L and H variants, or basically 5.56mm and 7.62mm NATO. The H has an upper that's nearly an inch longer than the L variant, let alone much wider. Also, considering that most of the caliber conversions (such as 7.62x39) have focused on the H variant, I've wondered and come to think that the L is optimized around 5.56mm. I actually can't remember there being any caliber conversions offered for the SCAR 16 aside from .300 Blackout. What has gotten me thinking about the 433 maybe being 7.62mm NATO compatible with a lower, barrel and bolt swap is, one, the TFB article referring to it. But I've also been told on HK Pro that, for instance, HK were shown or at least informed of the concept of the POF .308 chambered AR-15 upper. That's what got me thinking about seeking out an online image scaler/measure feature. Which brings me to Sturgeon saying that it's well within margin of error. Emphasis on the word error on my part. I'm very, very doubtful that my measurements are exact. Also, I haven't been able to locate the length front to rear of a .308 HK mag or SR-25 mag. Granted, I've measured a few photos of the 433 in the same method, and though the measurements haven't come out exactly the same each time, they've fallen into the same 71-72mm range. Which given variations in photos, my un-steady hands and crappy eyesight, can maybe be considered a preponderance of evidence (?). Of course, if the 433 can take .308/7.62mm sized rounds in terms of width and length, that can open up a lot of things, given that the 433 would be a pretty compact rifle for barrel length in those larger calibers. Granted, all the 433's that have been show are not only in 5.56mm, but are marked as 5.56mm on the upper, though the rifles shown are basically the versions they're trying to pitch to the German Army.

Measurements are in millimeters. Upper measurement is OAL, lower measurement is length of the rear of the front trunnion to approx end of mag well: The position of the TE of the rear turnnion was determined from this:

I'm not going to rubbish the Minimi/M249 and stuff like it as weapons designed for a purpose, since they suit that purpose well. What I'm questioning is does an infantry rifle squad need a belt fed MG that actually doesn't weigh a ton less than a light weight 7.62mm/.30 cal belt fed like say a Mk48 or a PKM? It has to be remembered that the M249 and the MG4 and the like are belt fed in part to provide some sustained fire capability. I agree that at the squad level a SAW should fired the same rounds as the infantry rifle does, but I do think that a mag fed weapon, sort of a heavy barreled assault rifle, would be better for squad tactics. Especially if you're trying to do hit and run. Something like the Ultimax or similar in concept would be excellent for such tactics. I might revise this thought if there was a belt fed SAW that weighs less than like 11-12 lbs that is in common use. I know of Knight's Armament LAMG, but so far it's being looked at by the same type of people who took the Stoner 63 LMGs seriously in Vietnam. IE, spec ops. In deference to that, I do think that the platoon or company level weapons should be a heavier caliber for squad support. Basically what I envision a GPMG should be able to do. That's where I see both heavy caliber and sustained firepower being insanely useful. But for the squad, I don't think that in most instances .30 caliber rounds are needed, nor the weight of the GPMG--5.56mm belt fed SAWs are already being criticized by some for being too heavy for their caliber. Hell, even during the original US Army SAW trials in the 1970s the USMC favored the XM106, which was a heavy barreled M16 with a QCB facility. And that basic concept was revived with the Marine's IAR program. Either way, both concepts have their strengths and weaknesses, but what is prized more by an infantry squad: mobility or sustained fire? I guess that depends on who you ask for right now.

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

Just commenting on what I read in this thread. One of the criticisms I read was how difficult the EM-2 would've been to mass produce with 1950's tech. Yes, we built nearly 6 million M1s in World War II, as well as numerous BARs, Browning 1917s and 1919s and Thompson SMGs that relied heavily on forgings for assembly. Also, Enfiled made the Bren LMG, which was made almost entirely out of forgings. But two things are worth remembering. One, for the Bren, until it was made in Canada, almost all Bren LMGs were made at Enfield, and there was a worry that if the factory was badly damaged enough in an air raid that Bren production would've been crippled until the factory could be repaired. And two, I wouldn't want to go to war against the Russians in the Cold War if shit hit the fan and World War II broke out between the Warsaw Pact and NATO knowing that I had a great rifle, but it costs a relative fortune in time and money to make. The AK-47 or the AKM, probably a much inferior rifle than the EM-2 performance-wise, but especially the AKM could be made in larger numbers quicker and cheaper. Paradoxically, the SA80's problems really began in earnest due to Enfield by the late '60s or early '70s having most of the design talent having retired or gone elsewhere (such as EM-2 designer Stefan Janson going to the US to work for Winchester after the EM-2 program ended), combined with the demands to make the rifle cheap on top of that. And yes, I read your commentary on the .280, where you basically said (as the ARES blog article on the EM-2 also commented) that 280 as it was wasn't an optimal round compared to 7.62mm NATO for the given time. One issue that the British had was simply what should they use for bullet cores. The ideal cartridge committee recommended steel or tungsten cores for rounds between .250 to .270 caliber, but if they had to stick to steel or lead, then they'd be better off going .270 or larger in caliber. And I do remember the comments that the steel cored rounds had erratic accuracy. Of course, I do question why the British opted for trying steel cores for .280 ball ammo (even 5.56mm M193 still used lead cores). I know that the Russians did it for 7.62x39mm for cost and barrier penetration reasons, but I doubt that was well known to anyone outside of the Soviet Union/Warsaw Pact at the time (early to mid-1950s). And the US Army (though much of it was the old "Not Invented Here" adage speaking) was critical of the .280 round's trajectory at longer ranges. Cited on Forgotten Weapons is that when shot out to 800 yards, .280 would tend to miss and fly over anyone at 400 yards when being shot at with a rifle zeroed for that 800 yards even with a center of mass aim. Of course, the same reports cited also argued that 7mm rounds didn't have enough capacity for tracer elements or incendiary filling (both of which are obvious BS, as 5.56mm proved). And of course, cold weather (like in the arctic) or in Russian winters would make that issue worse. Of course, the whole irony with that is that the US Army shortly there after (starting near the end of the Korean War I believe) to research SCHV rounds, like say .22 rounds. And yes, modern SCHV rounds will do better in terms of ballistics than the .280 will. However, even early 5.56mm ammo wasn't at it's best when pushed out to it's max range (which is why the 6mm SAW was worked on for a while), and what we have now, we have the benefits of decades worth of R&D, something that the British didn't have when .280 was developed. As for the construction of the EM-2. I've been reading this thread, and I'm wondering how they intended to make it. I may not understand it completely, which isn't helped that it never did make it mass production, but it does seem to be a fairly complicated rifle to make. It seems almost akin to the Thompson SMG, which was criticized for being a pain to mass produce. For all of that, though, not even the M3 completely replaced it and the Thompson remained in production until the end of World War II. At least the EM-2 as far as mis-handling ought to have been a tank like the FAL or the forged AKs tend to be. However, a lot of this is hard to say beyond those who used and handled EM-2 have said and contemporary reports. Seeing Forgotten Weapon's videos on the EM-2, I do generally agree it was probably the best Cold War rifle that never was. And it's damn sure better than the SA80 that the British Army ended up with until HK overhauled them (and that was just HK tuning up the SA80 to the production standards and fit and finish standards they should've been built to in the first place). Naturally, none of this conjecture is helped by the fact that only 59 EM-2s ever got built, and it wasn't adopted long enough for much to happen aside from field trials.

Wonder if anyone would be interested in me posting at least links to HK433 patent images. I'm also open to discussing the rifle in an appropriate area given what me and Sturgeon have mentioned in the Ammo Discussion thread.

I'm not going to bash the EM-2 as a concept, but in some ways it was flawed. Namely, as has been pointed out, in it's original for, the .280 round (like most non SCHV intermediate rounds) has issues with accuracy due to a fairly heavy bullet being propelled at fairly low velocity. Like Ian pointed out in his EM-2 and .280 FAL videos and Forgotten Weapons articles, .280, though designed mostly as a 600 yard round, tended to have a high arc between the muzzle and most of the longer ranges it was intended to be used in. If it was chambered in the 6.25mm/.280 (6.25x43mm round) or the intended 6.25x46mm round (sort of a shorter OAL 6mm SAW) or even 5.56mm NATO, it would've been more effective across all ranges. Biggest issue I have with the EM-2, as already mentioned, was it would've been a relative pain in the ass to mass produce. The EM2, like say the FN FAL, had a forged receiver, a steel forged receiver. Not forged aluminum, or extruded aluminum, but forged steel. The original mass produced AK-47s that had forged receivers were replaced with the AKM (perfected stamped receiver) due to cost and production reasons. FN even tried to make investment cast receivers for the FAL in the 1970s to reduce costs and speed up production times. If the EM-2 was made from forged aluminum or an aluminum extrusion, it would've been great, but that technology had yet to be proven in the late 1940's/early 1950s. Not to mention that the EM-2, as good as it was, never the less still had the normal issues that most bullpups have in regards to ergonomics. They're short and handy, but most bullpups don't have length of pull or cheek weld adjustable stocks, and if you're among the 10% of people who happen to be left handed, you're kinda screwed. One of the things that HK couldn't fix on the SA80 was it's right hand ejection only, and hence almost impossible to fire left handed if you're a southpaw or from cover. The AUG and FAMAS can be converted to right or left ejection, but that requires a field strip and a new bolt or replacing parts on the bolt. So the EM-2 in my opinion? Very good rifle, but would've been better in a newer, more modern caliber and more modern production techniques. Not to mention in some ways the .280 and .308 FALs were superior to the .280 and .308 EM-2s from a practicality stand point. Ironically, if a production optimized/modern EM-2 was out today in .308 and Enfield were still making firearms, they'd kinda have a bullpup HK433 in as far as (alleged) caliber conversions. After all, there's a chance that the 433 was designed by HK to take rounds up to .308 though being rebarreled and fitted with a new bolt and lower.

On the HK Pro board, I've been discussing with others if the 433 was designed to take up to 7.62mm NATO/.308 rounds as far as width/OAL. As far as is known, only the 5.56mm versions have been shown publicly thus far, though they've said for sure that versions in 7.62x39mm and .300 Blackout will be out shortly after the 5.56mm version is released (if it gets adopted by the German Army), and from what I can tell, will likely be available for conversion though different bolts, lowers, barrels and mags. Also, again messing around with with a photo scaler/measurer, it does seems to be more possible that the 433 upper can maybe take .308 Win/7.62mm NATO with few if any modifications. Newer measurements I've taken is that the distance between the approx TE of the mag well and where the ending of the front trunnion is indicated on patent drawings indicates a length of 71-72mm. Not quite enough to fit a .308 in a mag, but then again, I'm being a bit conservative with my measurements. Of course, it'd help big time if photos of the 433 field stripped and of the upper and lower internals existed. Someone from HK Pro has said that the reason why this might or might not work out is that POF's .308 chambered AR-15 (not an AR-10, an actual AR-15 upper in .308) was shown to HK designers. Also, consider this factoid. An HK433 with a 16.5 inch barrel with a folded stock is 28.23 inches. A FN SCAR 16 with the same barrel length with a folded stock is only .4 of an inch shorter, which the longer length of the 433 can be at least partly explained in that the stock latch (fixed to the rear of the upper) is counted as OAL, and obviously adds some to the OAL with a folded stock. And it does have to remembered that HK designed the 433 as a competitor to the SCAR before they pitched it to the German Army to replace the G36. And as such, it has to bring something new to the table to be a serious competitor. I'd love to know if that was the intention and such. That all being said, the 433 would probably be a caliber conversion dream. Though the current lower is restricted to 57.4mm/2.26 in rounds, it does seem that a barrel, bolt and lower/mag swap is very easily doable to many calibers. Also, as to caliber, I know that a lot of people favor the bigger hole theory, which is nice and all. However, smaller caliber rounds are lighter, flatter shooting, when done right they have a ton more stopping power and lethality than their size suggest (after all, game significantly larger than human sized has been taken down by .223 Rem/5.56mm NATO), and as you've pointed out on a blog I commented on, smaller caliber HV rounds do tend to yaw/tumble more readily in a shorter distance vs larger caliber rounds, which all spitzer bullets do to one degree or another already. SCHV just tend to do it better and quicker.

I was actually reading some stuff on ammo at TFB, and I have to admit that I'm not the biggest fan of being constrained to the 56mm-57.4mm OAL rounds that the AR-15 and AK-47/47 platforms have proliferated. However, I really like the .224 Vulcan and 6.86mm Romulan rounds that were hypothetically created. Both do things well in different ways. 6.86mm is basically a .276 Pedersen capitalistically (which I think .276 is an underrated round), while the .224 Vulcan is a .223 Remington/5.56mm NATO or .224 Valkyrie on roids. The 6.86 does punch a fairly big hole, while the .224 suits the SCHV with an effective long range round that might be good for use against some forms of body armor at longer ranges. This doesn't take away from modern 5.56mm rounds like M855A1 or Mk 318 or Mk 262, however. But I to think that the rounds mentioned IMO do reinforce my favor or modern modular rifles like the HK433 or the FN SCAR. For example, I was just dickin' around with a photo scaler/measurer and a photo of an HK433 and also examining some patent illustrations that you can find on Google patents. I haven't done this with the SCAR yet (and I think that the SCAR 16 wouldn't be the best candidate for this as it is, since I don't know if it can take rounds wider than 5.56mm as far as base/rim diameter), but the 433 it seems can take rounds up to about 66-67mm (maybe longer even, though not much). Which means from what I can tell it can't take .308 WInchester/7.62mm NATO or 6.5mm Creedmoor or .276 Pedersen without a modded upper, but if you change lowers, barrels and bolts, if the 6.86mm and .224 Vulcan were real, they'd be good round for the 433 and similar modular rifles (the 433 also has clearance bulges on the upper to accommodate rounds at least .447 wide, since it's designed it seems to be rebarreled to 7.62x39mm). It can also take real life rounds like .280 British or 6x45mm SAW as well.