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Posted: 10/22/2025 6:30:38 AM EDT
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Came across this on X, a Jap guntismo account that is usually flawlessly researched. Rumor of SOCOM pursuing a new upper that can handle the SIG 5.56 MAX/HYP 80kpsi loads as well as Shell Shocks high performance steel cases. Anyone heard any similar scuttlebut about this? https://x.com/teppoblog/status/1979797885811388614  https://x.com/2805662/status/1941256932352049250
 https://soldiersystems.net/2025/02/12/sig-sauer-global-defense-range-demo-day-ammunition/ One of the biggest announcements was that new military caliber ammunition using the hybrid case will be referred to as HYP for Hybrid Performance and pronounced “hype.” Their 5.56 HYP is demonstrating a +400 fps increase over M855A1. Naturally, that comes with even higher chamber pressures than M855A1, but the increase in velocity is impressive.  SIG SAUER Defense Range Day 2025 – Ammunition Demonstration |
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Some 5.56 MAX specs from a guy who works for Janes. 62gr @ 3182fps from an 11.5"
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Some very random thoughts, may or may not be based in reality: -I thought M855A1 was already pushing toward 70kpsi as it is? -If they wanted to run an 80k psi round, it seems like they would be looking at an all new upper design, or at least new bolt metallurgy that doesn't exist today, to keep it safe and reliable. -If 80kpsi 556 ever made it onto the civilian market, you might have a real, legitimate/serious safety issue about keeping it out of the vast majority of guns on the market which aren't designed for that. Not the normal 223/556 argument, like... an actual problem. |
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Good grief!! I'll bet that shooter needed new pants. Hopefully no human damage. |
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Quoted: Some 5.56 MAX specs from a guy who works for Janes. 62gr @ 3182fps from an 11.5"
Thanks Spydermonkey  As your post points out: “Max cannot be used by legacy rifles.” OK But presumably, “legacy ammunition” would still work in new rifles designed for 556 MAX. Also, a prior USGI loading has been made in 3 versions, some of which would KB earlier or “legacy” rifles: U.S. 45-70. Some guns were black-powder only, some were “smokeless” (but only to a certain PSI) and some modern guns chambered in 45-70 can handle much hotter loads (Ruger #1 rifles, and some bolt action rifles). But all 3 loads will “fit” the same chamber. Max is not perfect (nothing is). But I like the idea more than the 6.8. |
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Quoted: Some very random thoughts, may or may not be based in reality: -I thought M855A1 was already pushing toward 70kpsi as it is? -If they wanted to run an 80k psi round, it seems like they would be looking at an all new upper design, or at least new bolt metallurgy that doesn't exist today, to keep it safe and reliable. -If 80kpsi 556 ever made it onto the civilian market, you might have a real, legitimate/serious safety issue about keeping it out of the vast majority of guns on the market which aren't designed for that. Not the normal 223/556 argument, like... an actual problem. M855A1 stays around 60k or less, it's been nerfed a bit |
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Quoted: Good grief!! I'll bet that shooter needed new pants. Hopefully no human damage. Quoted: Good grief!! I'll bet that shooter needed new pants. Hopefully no human damage. Blew the mag out the bottom, shooter felt something hit him but didnt leave a mark. |
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Quoted: I was under the impression that the shell shock stuff provided similar results without the need of special uppers and bolts? The current loads with Shell Shock are achieving higher velocities by leveraging the ~8% increase in internal powder capacity afforded by the thin wall steel case design. So they are operating at normal pressures and can be fired out of normal rifles. However the SS case can also handle higher pressures up to ~70kpsi or so. The .264 LICC used in FN's new IWS rifle is reportedly using the SS case at 70kspi. It uses a beefy triangular bolt to ensure durability. |
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Will the 556HYP cartridge chamber in a normal M4 or is it engineered to prevent it from chambering? That sounds like an accident waiting to happen if so. Will the new uppers/guns be able to chamber both? Have there been advances in barrel technology to maintain barrel life with the higher pressure round? |
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Quoted: The current loads with Shell Shock are achieving higher velocities by leveraging the ~8% increase in internal powder capacity afforded by the thin wall steel case design. So they are operating at normal pressures and can be fired out of normal rifles. However the SS case can also handle higher pressures up to ~70kpsi or so. The .264 LICC used in FN's new IWS rifle is reportedly using the SS case at 70kspi. It uses a beefy triangular bolt to ensure durability. Shellshock seems like the way to go then. As others have mentioned the sig offering sounds like an accident waiting to happen for consumers and mil users. Also seems the most economical |
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Quoted: Will the 556HYP cartridge chamber in a normal M4 or is it engineered to prevent it from chambering? That sounds like an accident waiting to happen if so. Will the new uppers/guns be able to chamber both? Have there been advances in barrel technology to maintain barrel life with the higher pressure round? No idea / official word. But I imagine the 5.56HYP / MAX is just a regular 5.56 shape with no changes to prevent chambering. I imagine this is being treated as 'SF use so big boy rules' in terms of safety and liability. Since the brass body / shiny steel base is very visually distinct, they are probably hoping that will be enough. The 6.8 NGSW M7 rifles have been shown to be able to fire both High Pressure and Regular brass ammo. So I assume the new High Pressure 5.56 upper would be designed to be able to fire both legacy 5.56 and newer higher performance rounds. Ideally, they would do a "5.56 AI" Ackley Improved (someone email this to SIG). -Prevents chambering High Pressure 5.56 in regular guns -AI chamber can still fire legacy brass 5.56 -AI boosts powder capacity for even more velocity  ... In terms of barrel tech, the fancier steel used in the HK 416 can go up to 40k rounds, ~2x the barrel life of a normal 4150 CHF CL barrel made with. So that seems like a good starting point for a high pressure barrel. https://www.aubertduval.com/en/products/armad-through-hardening-steels/ SOLGW is supposed to start offering barrels in this steel, although no idea if they have the CHF and heat treatment of the 416. But promising the US is finally trying something other then 4150. |
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Quoted: Shellshock seems like the way to go then. As others have mentioned the sig offering sounds like an accident waiting to happen for consumers and mil users. Also seems the most economical Quoted: Quoted: The current loads with Shell Shock are achieving higher velocities by leveraging the ~8% increase in internal powder capacity afforded by the thin wall steel case design. So they are operating at normal pressures and can be fired out of normal rifles. However the SS case can also handle higher pressures up to ~70kpsi or so. The .264 LICC used in FN's new IWS rifle is reportedly using the SS case at 70kspi. It uses a beefy triangular bolt to ensure durability. Shellshock seems like the way to go then. As others have mentioned the sig offering sounds like an accident waiting to happen for consumers and mil users. Also seems the most economical I'm a huge fan of the SS case and think its a better general purpose design. But for Armor Piercing ammo, the 80kpsi of the SIG may be worth it. 5.56 will need every single fps it can get to defeat modern Level IV (plus massively improved tungsten bullet design over legacy M995). This is exacerbated by the use of shorter barrels. If i had to guess the interest in High Pressure is being driven more by AP desires than increased range. The low ballistic coefficient of legacy 5.56 projectiles quickly strips away the velocity gains downrange. M855A1 @ 3000fps = 1700fps @ 460yd M855A1 @ 3400fps = 1700fps @ 585yd Better, but +125yd range might not be worth a completely new weapons and ammo. |
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This whole thing (as well as other 5.56x45 bullet improvements) is more than enough justification for the 1:7 twist included in my M16A2 development program in 1980-1983. And for those of you who may remember, that was not without controversy from tons of "experts." Hey ColdBlue, isn't that like 40 some years ago or so...? |
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Quoted: The new advanced steel by Albert&Duval will be 5 times more expensive than standard mil spec barrel steel. I know this because I asked. Perhaps, if it became widespread, it would come down in cost. HK's 416 seems to be cost competitive / roughly so with other military piston rifles, especially for large military contracts. I also wonder if any of the high performance US steel companies who produce steel for pocket knives and turbine blades might have something roughly equivalent; 4150 barrel steel is quite old so it strains credulity that they couldn't create something better here in the US. Worse case we could see current FN / DD ~20krd service life CHF CL 4150 barrels reduced to ~6,000rd service life - which is currently the spec for the button rifled M4A1 barrel in military testing. |
A 3rd option - and possibly the best option - is Federal's new PEAK alloy cases. Currently in use in the 7mm Backcountry, they have shown 5.56 test samples before. https://x.com/teppoblog/status/1981240552428593169 G$ showed off the PEAK 5.56 in their guns (unknown if modified)  Federal’s Peak Alloy is changing ammo w/ 7mm BC. This case tech increases velocity w/ similar recoil 64gr from a 14.5" comparison 
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If they feel they need a more powerful cartridge, how long before they switch to 6arc or something else that can be accomplished with a rebarrel instead of continuing to the hotrod the 556, and instead of the 6.8x51 debacle? With 80kpsi 5.56, you are going to need new uppers as well as unique/not backwards compatible ammo... same as you would with a different small frame cartridge. Seems like logistics would be greatly streamlined as well as it being a much more well rounded general purpose option vs an all new large frame gun in the 6.8 Spear. |
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Quoted: If they feel they need a more powerful cartridge, how long before they switch to 6arc or something else that can be accomplished with a rebarrel instead of continuing to the hotrod the 556, and instead of the 6.8x51 debacle? With 80kpsi 5.56, you are going to need new uppers as well as unique/not backwards compatible ammo... same as you would with a different small frame cartridge. Seems like logistics would be greatly streamlined as well as it being a much more well rounded general purpose option vs an all new large frame gun in the 6.8 Spear. High-pressure ammo is going to be the way forward no matter what (see: NGSW) because smashing through plates is all about kinetic energy - which increases exponentially with velocity on impact compared to projectile mass. You have to jump the pressure a lot less on a lighter projectile to get the kinds of velocities that they seem to be looking for. |
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Quoted: No idea / official word. But I imagine the 5.56HYP / MAX is just a regular 5.56 shape with no changes to prevent chambering. I imagine this is being treated as 'SF use so big boy rules' in terms of safety and liability. Since the brass body / shiny steel base is very visually distinct, they are probably hoping that will be enough. The 6.8 NGSW M7 rifles have been shown to be able to fire both High Pressure and Regular brass ammo. So I assume the new High Pressure 5.56 upper would be designed to be able to fire both legacy 5.56 and newer higher performance rounds. Ideally, they would do a "5.56 AI" Ackley Improved (someone email this to SIG). -Prevents chambering High Pressure 5.56 in regular guns -AI chamber can still fire legacy brass 5.56 -AI boosts powder capacity for even more velocity https://forum.accurateshooter.com/proxy.php?image=http%3A%2F%2Faccurateshooter.net%2FProducts%2F223ackleyx580a.jpg&hash=32137eeb6b23a4c710708aab356401e6 ... In terms of barrel tech, the fancier steel used in the HK 416 can go up to 40k rounds, ~2x the barrel life of a normal 4150 CHF CL barrel made with. So that seems like a good starting point for a high pressure barrel. https://www.aubertduval.com/en/products/armad-through-hardening-steels/ SOLGW is supposed to start offering barrels in this steel, although no idea if they have the CHF and heat treatment of the 416. But promising the US is finally trying something other then 4150. Quoted: No idea / official word. But I imagine the 5.56HYP / MAX is just a regular 5.56 shape with no changes to prevent chambering. I imagine this is being treated as 'SF use so big boy rules' in terms of safety and liability. Since the brass body / shiny steel base is very visually distinct, they are probably hoping that will be enough. The 6.8 NGSW M7 rifles have been shown to be able to fire both High Pressure and Regular brass ammo. So I assume the new High Pressure 5.56 upper would be designed to be able to fire both legacy 5.56 and newer higher performance rounds. Ideally, they would do a "5.56 AI" Ackley Improved (someone email this to SIG). -Prevents chambering High Pressure 5.56 in regular guns -AI chamber can still fire legacy brass 5.56 -AI boosts powder capacity for even more velocity https://forum.accurateshooter.com/proxy.php?image=http%3A%2F%2Faccurateshooter.net%2FProducts%2F223ackleyx580a.jpg&hash=32137eeb6b23a4c710708aab356401e6 ... In terms of barrel tech, the fancier steel used in the HK 416 can go up to 40k rounds, ~2x the barrel life of a normal 4150 CHF CL barrel made with. So that seems like a good starting point for a high pressure barrel. https://www.aubertduval.com/en/products/armad-through-hardening-steels/ SOLGW is supposed to start offering barrels in this steel, although no idea if they have the CHF and heat treatment of the 416. But promising the US is finally trying something other then 4150. Hodge barrels can also go about 40k rounds using FN's proprietary steel and lining, which is probably 41V45 steel with 2x thick chrome lining. It isn't clear if SOLGW actually has any relationship with AeB since they apparently bought a bunch of bar stock remaining in the US. However, there are probably novel advancements to barrel tech on the horizon anyways. Quoted: The new advanced steel by Albert&Duval will be 5 times more expensive than standard mil spec barrel steel. I know this because I asked. Perhaps, if it became widespread, it would come down in cost. Yeah this is nonsense for the US market, especially if it means a SOLGW barrel would be ~$1500. This sounds like SOLGW is buying them from a middleman. Quoted: I also wonder if any of the high performance US steel companies who produce steel for pocket knives and turbine blades might have something roughly equivalent; 4150 barrel steel is quite old so it strains credulity that they couldn't create something better here in the US. Inconel and other extreme durability alloys are usually hard to machine and require special tools. Additive manufacturing can solve this. |
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Quoted: The law of physics applies to everyone. IMO, there is nothing wrong with the performance of 5.56mm @ 62,000 psi. I'm not looking forward to reports of broken bolts on the front lines. Which laws of physics are being broken? Advanced materials can often seem like magic until they see widespread adoption. This has happened multiple times in the firearms world. |
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Some of the higher velocity 5.56 using Shell Shock NAS3 cases using 55gr FMJ. Note that NAS3 is leveraging increased powder capacity not pressure here; this works better with lighter/shorter projectiles because you have even more powder space. I dont think the +fps is as dramatic when you're going with long lead free projectiles like M855A1, although there would still be solid velocity gains. 
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Quoted: Some very random thoughts, may or may not be based in reality: -I thought M855A1 was already pushing toward 70kpsi as it is? -If they wanted to run an 80k psi round, it seems like they would be looking at an all new upper design, or at least new bolt metallurgy that doesn't exist today, to keep it safe and reliable. -If 80kpsi 556 ever made it onto the civilian market, you might have a real, legitimate/serious safety issue about keeping it out of the vast majority of guns on the market which aren't designed for that. Not the normal 223/556 argument, like... an actual problem. New bolt metallurgy? Ok. Consider this. We’ve been using the 5.56 in the military for what… coming up on 70 YEARS. think about that for a moment. In 70 years there have been leaps and bounds in metals and in design tech. As someone mentioned the 45-70 years ago went through the same progression. I want to see some developers start pushing to a reliable 100K as a civilian or military cartridge. There’s been some publically known experiments that come to mind. But it seems as if 65k is the line we sort of rested on. Heck. I have a revolver that uses a 65K cartridge in factory ammo at this point. I’m not a designer or an engineer. But I do know how to critically look at something and say hey. Adding a little material right here or doing “X” will gain us improvements over the standard we have now. We have room for improvements that will allow a soldier to not reduce capacity. Improve cartridge performance and terminal ballistics while also not having to recreate all of our equipment from scratch. But th person I quoted is right on a huge topic. People can make poor decisions and invariably will decide to load that 556 max into a regular AR. It will need to be slightly different give the shoulder the “Ackley Improvement” shoulder to add a tiny bit of capacity and it will ensure that you can’t chamber it in a 5.56 rifle. Benifit is that you could still fire regular 5.56 in it. It would fire form the cases. To the new shape. But they would no longer work with regular 5.56 dies and thus a reloader not likely to make the mistake of reloading them. Thoughts? Or am I way off base here. Heck. Where’s Tony. He’s known for making some crazy neat stuff @TonyRumore |
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The Ruger SFAR uses a standard size AR-15 bolt with a .473" pocket, standard size AR-15 barrel extension, and chambered in .308 as well as 6.5 Creed. That would break a standard Carpenter 158 or 9610 bolt. The material they are using for the bolt and extension is C300 Maraging steel, also known as Vascomax 300. We verified this with our metal analyzer. They tested this setup to about 120,000 psi which is the max limit for the pressure transducers. If you were to reduce the diameter of the bolt pocket, it could probably handle even more. I'm not sure why there is a pressure transducer limit of 120k, but that seems to be the ceiling for those types of pressure transducers used in the firearms industry. Tony Rumore Tromix Edited to add: I got a quote on that material. 1.25" diameter round bar runs $938 per foot, 20 foot minimum, 2 week lead time. That's going to run you $19,000 to try it. |
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Quoted: The Ruger SFAR uses a standard size AR-15 bolt with a .473" pocket, standard size AR-15 barrel extension, and chambered in .308 as well as 6.5 Creed. That would break a standard Carpenter 158 or 9610 bolt. The material they are using for the bolt and extension is C300 Maraging steel, also known as Vascomax 300. We verified this with our metal analyzer. They tested this setup to about 120,000 psi which is the max limit for the pressure transducers. If you were to reduce the diameter of the bolt pocket, it could probably handle even more. I'm not sure why there is a pressure transducer limit of 120k, but that seems to be the ceiling for those types of pressure transducers used in the firearms industry. Tony Rumore Tromix Edited to add: I got a quote on that material. 1.25" diameter round bar runs $938 per foot, 20 foot minimum, 2 week lead time. That's going to run you $19,000 to try it. Technology marches along. We’ve been stagnant. The next big step in firearm tech will be higher pressure cartridges. There was some guys that had a great YouTube video on reloading and testing a 308 to over 100K psi. Showed the brass and accuracy info and where it fell off. I can’t seem to find it though. |
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Federal’s Peak Alloy is changing ammo w/ 7mm BC. This case tech increases velocity w/ similar recoil Geissele posted this video of Peak alloy cased 5.56mm a while ago. Federal 64gr Bonded picks up 300fps in a 14.5" barrel. Cool stuff we will probably never see commercially. eta: beat, didn't read past OP |
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Quoted: The current loads with Shell Shock are achieving higher velocities by leveraging the ~8% increase in internal powder capacity afforded by the thin wall steel case design. So they are operating at normal pressures and can be fired out of normal rifles. However the SS case can also handle higher pressures up to ~70kpsi or so. The .264 LICC used in FN's new IWS rifle is reportedly using the SS case at 70kspi. It uses a beefy triangular bolt to ensure durability. Quoted: Quoted: I was under the impression that the shell shock stuff provided similar results without the need of special uppers and bolts? The current loads with Shell Shock are achieving higher velocities by leveraging the ~8% increase in internal powder capacity afforded by the thin wall steel case design. So they are operating at normal pressures and can be fired out of normal rifles. However the SS case can also handle higher pressures up to ~70kpsi or so. The .264 LICC used in FN's new IWS rifle is reportedly using the SS case at 70kspi. It uses a beefy triangular bolt to ensure durability. What is the case head diameter? |
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Barrel life with NATO pressure 5.56 is pretty well known. Extrapolating what I know about pressures and throat erosion from reloading... and seeing a future in the stocks of companies that sell barrels. There's always been the ability to trade equipment life for moderately hotter ammo. It's just a really expensive thing to do to yourself. |
| Testing 80K psi 5.56 loads is to be expected, anyone actually adopting a 80K 5.56 load is fooling themselves. Yes, you get higher velocity, but velocity increases has never been what any of the militaries using 5.56 have been trying to find. All the changes to the original 55 grain 5.56 load have been heavier bullets, now using a 77 grain bullet that is at the maximum that can be used without changing to a longer magazine. Time to go to a larger diameter bullet to get a heavier bullet, whether it's a 6mm, 6.35mm (25 caliber) or 6.5mm. Lightest military load that I know of that never had complaints was the old 6mm Lee-Navy round that used a 112 grain bullet. So you need a ~2.5-2.75 inch magazine and a larger .421 (30 Rem/6.8SPC) or .441 (7.62x39) case head with a ~115 grain bullet going at least 2700fps. Aiming to hit a sweet spot that allows controllable full auto fire yet enough power to have single hit knockdown capability at 600 meters. If 100K psi levels can do this without wearing out barrels then you can use a little shorter cartridge and magazine, otherwise you need to stay at 65K or 80K pressure levels to not wear out the barrel. |
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