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Quoted: It's more or less understood in the engineering world that you build to 2x the anticipated stress. Say a rifle cartridge generates 55kPSI. Build an action to withstand 110kPSI and it'll last forever. Build a residential electric transformer to handle 50KVA and it'll handle a 25KVA load practically forever. Build a revolver cylinder to withstand 80kPSI and it'll withstand 40kPSI practically forever. But when you push pressures beyond that halfway point, you get on a sliding scale between 'lasts forever' and 'grenades on the next shot'. And it's really hard to predict the slope of that slide. It's entirely possible that the destruction in the OP video was the result of a single grossly overpressure shot, but it's also possible, and IMO more likely, that the rifle was being damaged by a series of overpressure shots, and the last one was the proverbial straw breaking the camel's back. View Quote View All Quotes View All Quotes Quoted: Quoted: Having the recoil be absorbed by nothing but those end cap threads seems more than a little suspect. I wouldn't be too keen on trusting those even before seeing this video. Isn't there a theoretical maximum pressure a given caliber can physically have, given powder types and case volume? Why wouldn't they add a safety margin equal to that maximum? The guy said normal 50 cal pressure is 55,000psi and that this round was probably 85,000psi. I know over building has a cost but this guy almost died and by all accounts should have. It's more or less understood in the engineering world that you build to 2x the anticipated stress. Say a rifle cartridge generates 55kPSI. Build an action to withstand 110kPSI and it'll last forever. Build a residential electric transformer to handle 50KVA and it'll handle a 25KVA load practically forever. Build a revolver cylinder to withstand 80kPSI and it'll withstand 40kPSI practically forever. But when you push pressures beyond that halfway point, you get on a sliding scale between 'lasts forever' and 'grenades on the next shot'. And it's really hard to predict the slope of that slide. It's entirely possible that the destruction in the OP video was the result of a single grossly overpressure shot, but it's also possible, and IMO more likely, that the rifle was being damaged by a series of overpressure shots, and the last one was the proverbial straw breaking the camel's back. The sequence of shots that he took, with erratic muzzle blast and impacts, does suggest that he fired several rounds over proof in just that video. If he had fired more over pressure rounds prior to those in other videos or off camera, chances are the thread shearing on that last shot was the result of the cumulative effects of all of that. I am very glad that he has all of his parts and can still count past 5. |
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I though I heard in a Forgotten Weapons video or somewhere else that 50BMG SLAP rounds were only supposed to be used in M2 machineguns and not in bolt or semi-auto rifles.
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I believe that has to do with the plastic discarding sabots hitting modern muzzle brakes. Only a danger to people from plastic coming out the ports.
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Quoted: It's more or less understood in the engineering world that you build to 2x the anticipated stress. Say a rifle cartridge generates 55kPSI. Build an action to withstand 110kPSI and it'll last forever. Build a residential electric transformer to handle 50KVA and it'll handle a 25KVA load practically forever. Build a revolver cylinder to withstand 80kPSI and it'll withstand 40kPSI practically forever. But when you push pressures beyond that halfway point, you get on a sliding scale between 'lasts forever' and 'grenades on the next shot'. And it's really hard to predict the slope of that slide. It's entirely possible that the destruction in the OP video was the result of a single grossly overpressure shot, but it's also possible, and IMO more likely, that the rifle was being damaged by a series of overpressure shots, and the last one was the proverbial straw breaking the camel's back. View Quote The problem here isn't the factor of safety. This was so catastrophic that it looks the same would have happened even if it was built to handle 110ksi. The problem is that the cheap design has no additional safeguards in the event of catastrophic failure. Because there is no large bolt, all that energy is directed to accelerating a small cap, which essentially becomes a very good projectile. There is no receiver to contain the debris/projectile so it has a clear path to the shooter other than 2 small ears which also became projectiles. None of this is true with a proper 50 BMG design from M99 to M107 |
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I have heard as well that you shouldn’t use slap rounds with a brake as the sabot can open up in the brake and cause an obstruction. I don’t know it that is accurate but it makes sense.
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Quoted: The T-rex got him. View Quote Nice! Woah Video did not do him justice. That looked like but a mere flesh wound when it happened, but to hear him go thru all the pieces of what happened during that. damn he is lucky to be upright and taking in nourishment. I always liked him, Matt and AK Jesus would not want to see any of them go that way Thank you lord for keeping a pro 2a guy here on earth where we need him. |
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Quoted: It's more or less understood in the engineering world that you build to 2x the anticipated stress. Say a rifle cartridge generates 55kPSI. Build an action to withstand 110kPSI and it'll last forever. Build a residential electric transformer to handle 50KVA and it'll handle a 25KVA load practically forever. Build a revolver cylinder to withstand 80kPSI and it'll withstand 40kPSI practically forever. But when you push pressures beyond that halfway point, you get on a sliding scale between 'lasts forever' and 'grenades on the next shot'. And it's really hard to predict the slope of that slide. It's entirely possible that the destruction in the OP video was the result of a single grossly overpressure shot, but it's also possible, and IMO more likely, that the rifle was being damaged by a series of overpressure shots, and the last one was the proverbial straw breaking the camel's back. View Quote This right hear. When I heard 55,000kPSI and 85,000kPSI. I was WAIT a second, say what??? That's different... and not in a good way. Plus mystery slap rounds... I have looked at those (back in the day, when they could be had easy and sorta cheap and was always???? Shutter.). I did collect a hand full of sabots and cores but have yet to hear good "safe" data on how to load them, and how the heck to shoot with without a break. LOL I even got a bag of over 100 of the sabots thinking geee maybe just use 30cal black tip.. lol But again, to chicken to make up a load or actually shoot them. |
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Quoted: Link? Only ones I know of are this and Vulcan crap. Never seen a serious injury from a Barrett but may simply be unaware View Quote View All Quotes View All Quotes Quoted: Quoted: Plenty of 50s explode with dudes coming in out in far worse shape. He’s lucky to be alive. Link? Only ones I know of are this and Vulcan crap. Never seen a serious injury from a Barrett but may simply be unaware My instinct was Vulcan before seeing the video. Regardless of opinion of this design, for those saying don't cheap out, would a Barrett have held together if the round was overpressure by as much as they estimate? |
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Quoted: The problem here isn't the factor of safety. This was so catastrophic that it looks the same would have happened even if it was built to handle 110ksi. The problem is that the cheap design has no additional safeguards in the event of catastrophic failure. Because there is no large bolt, all that energy is directed to accelerating a small cap, which essentially becomes a very good projectile. There is no receiver to contain the debris/projectile so it has a clear path to the shooter other than 2 small ears which also became projectiles. None of this is true with a proper 50 BMG design from M99 to M107 View Quote Attached File Attached File Or maybe that just creates more frag. |
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Quoted: I believe that has to do with the plastic discarding sabots hitting modern muzzle brakes. Only a danger to people from plastic coming out the ports. View Quote There is another channel that is up and coming and they shoot 50bmg SLAP rounds. They mentioned they had to swap to a non-braked barrel to shoot theirs. |
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“Cheap rounds” he said the SLAP rounds are $100 EACH.
Over pressure rounds. Serbu talked to him, average 50 BMG is 50000 psi. That round stripped the threads off of the barrel, estimated 80000 psi. Design precludes closing if cap not screwed completely on. Old unknown origin rounds (reloads? Storage?) in retrospect bad idea to shoot rounds of unknown province. |
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Those times when you take a knee and thank God for life.
Then wonder what kind of shit his yet has in store for you |
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Quoted: There is another channel that is up and coming and they shoot 50bmg SLAP rounds. They mentioned they had to swap to a non-braked barrel to shoot theirs. View Quote View All Quotes View All Quotes Quoted: Quoted: I believe that has to do with the plastic discarding sabots hitting modern muzzle brakes. Only a danger to people from plastic coming out the ports. There is another channel that is up and coming and they shoot 50bmg SLAP rounds. They mentioned they had to swap to a non-braked barrel to shoot theirs. The brake doesn't cause a kaboom, it can spit the sabots out sideways and otherwise fuck with the trajectory, which may explain the poor accuracy. |
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Unrelated article warning about nitriding gun parts....
https://attackcopter.com/2020/05/01/serbu-firearms-releases-psa-on-nitriding-high-strength-gun-parts/ Serbu Firearms states “PUBLIC SERVICE ANNOUNCEMENT: DON’T NITRIDE HIGH STRENGTH PARTS!!! Please share this far and wide because it illustrates how dangerous it is to expose heat-treated parts to a 1,000 degree F process! I don’t want to get into all the details about heat treating of steel, but just know that in general, if it’s high strength (like bolts, breech caps and muzzle brakes) it should NOT be nitrided! Yes, barrels are high strength but they’re not extremely hard so they can be safely nitrided. This customer didn’t know all this and had his entire RN-50 nitrided. Luckily when the muzzle brake grenaded it didn’t injure or kill anyone! What really scares the crap out of me is the breech cap. Yeah, I designed it with at least a safety factor of 3 (meaning it’s three times as strong as it needs to be) but now it’s somewhere around 2. Maybe. He’s going to get a new muzzle brake and new breech cap, but it’s not covered by warranty so he has to pay for it. Lucky he didn’t pay with an eye or with his life!” View Quote |
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Scary shit. I would not want a breech loaded .50 that close to my face.
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Quoted: Yell at me if I'm out of my lane, but it seems like it would be fairly easy to redesign that receiver to absorb a lot more energy from a blown cap and deflect it vertically by making the base of the "ears" full length, and perhaps adding a heavy plate in front of the stock extension. https://www.ar15.com/media/mediaFiles/172926/serbu1_png-1923534.JPG https://www.ar15.com/media/mediaFiles/172926/serbu2_png-1923536.JPG Or maybe that just creates more frag. View Quote View All Quotes View All Quotes Quoted: Quoted: The problem here isn't the factor of safety. This was so catastrophic that it looks the same would have happened even if it was built to handle 110ksi. The problem is that the cheap design has no additional safeguards in the event of catastrophic failure. Because there is no large bolt, all that energy is directed to accelerating a small cap, which essentially becomes a very good projectile. There is no receiver to contain the debris/projectile so it has a clear path to the shooter other than 2 small ears which also became projectiles. None of this is true with a proper 50 BMG design from M99 to M107 https://www.ar15.com/media/mediaFiles/172926/serbu1_png-1923534.JPG https://www.ar15.com/media/mediaFiles/172926/serbu2_png-1923536.JPG Or maybe that just creates more frag. I'm guessing the ears have nothing to do with containing the pressure, they just ensure the cap is on all the way and keep the action tight. Making them bigger may have deflect the cap upwards the and the frag to the sides, but it wouldn't stop it. Its interesting that the inside of the cap is not covered in brass dust, which may mean the case did not overtly fail. So maybe it was just a steady diet of hot ammo and the threads finally failed. |
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https://serbu.com/rn-50/
The RN 50 represents the first time a production firearm has ever been inspired by social media. Designed in conjunction with YouTube celebrity Royal Nonesuch. The RN 50 is a unique approach to the .50BMG rifle. Rugged, lightweight, accurate, easy takedown and low price make this rifle a winner! The simple screw on breech cap is not only strong, it applies absolutely symmetrical support to the cartridge case, allowing for incredible accuracy. Using top quality materials as well as parts from our proven BFG 50 rifle, the RN 50 gives you high quality at an incredible price, along with lineage to a safe, proven firearm that's been in production for 17+ years. Whether you're looking for the least expensive way to get into shooting .50BMG or you want to outshoot your friends' expensive match rifle, the RN 50 is for you! View Quote |
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Quoted: Unrelated article warning about nitriding.... https://attackcopter.com/2020/05/01/serbu-firearms-releases-psa-on-nitriding-high-strength-gun-parts/ 3x 50K PSI < 85K? View Quote What kind of dingdong buys the cheapest 50 in town then turns around and spends the coin to nitride coat it? |
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Quoted: Unrelated article warning about nitriding.... https://attackcopter.com/2020/05/01/serbu-firearms-releases-psa-on-nitriding-high-strength-gun-parts/ 3x 50K PSI < 85K? View Quote But the breech cap did not break apart did it? Also, I thought the threads on the barrel were sheared and not on the muzzle cap but I might be remembering that wrong? |
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Quoted: Having the recoil be absorbed by nothing but those end cap threads seems more than a little suspect. I wouldn't be too keen on trusting those even before seeing this video. Isn't there a theoretical maximum pressure a given caliber can physically have, given powder types and case volume? Why wouldn't they add a safety margin equal to that maximum? The guy said normal 50 cal pressure is 55,000psi and that this round was probably 85,000psi. I know over building has a cost but this guy almost died and by all accounts should have. View Quote The threads are not absorbing "recoil" The threads are holding the case head thrust. Typically known as "bolt thrust". You have confused two entirely different things. |
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Quoted: What kind of dingdong buys the cheapest 50 in town then turns around and spends the coin to nitride coat it? View Quote View All Quotes View All Quotes Quoted: Quoted: Unrelated article warning about nitriding.... https://attackcopter.com/2020/05/01/serbu-firearms-releases-psa-on-nitriding-high-strength-gun-parts/ 3x 50K PSI < 85K? What kind of dingdong buys the cheapest 50 in town then turns around and spends the coin to nitride coat it? The kind with a friend who works for a nitriding company? Or maybe the kind who works for a company that regularly sends parts out for nitriding? Doesn't make sense to me but then I'm not shocked either. Most people don't understand what "heat treated" means. |
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Quoted: The problem here isn't the factor of safety. This was so catastrophic that it looks the same would have happened even if it was built to handle 110ksi. The problem is that the cheap design has no additional safeguards in the event of catastrophic failure. Because there is no large bolt, all that energy is directed to accelerating a small cap, which essentially becomes a very good projectile. There is no receiver to contain the debris/projectile so it has a clear path to the shooter other than 2 small ears which also became projectiles. None of this is true with a proper 50 BMG design from M99 to M107 View Quote View All Quotes View All Quotes Quoted: Quoted: It's more or less understood in the engineering world that you build to 2x the anticipated stress. Say a rifle cartridge generates 55kPSI. Build an action to withstand 110kPSI and it'll last forever. Build a residential electric transformer to handle 50KVA and it'll handle a 25KVA load practically forever. Build a revolver cylinder to withstand 80kPSI and it'll withstand 40kPSI practically forever. But when you push pressures beyond that halfway point, you get on a sliding scale between 'lasts forever' and 'grenades on the next shot'. And it's really hard to predict the slope of that slide. It's entirely possible that the destruction in the OP video was the result of a single grossly overpressure shot, but it's also possible, and IMO more likely, that the rifle was being damaged by a series of overpressure shots, and the last one was the proverbial straw breaking the camel's back. The problem here isn't the factor of safety. This was so catastrophic that it looks the same would have happened even if it was built to handle 110ksi. The problem is that the cheap design has no additional safeguards in the event of catastrophic failure. Because there is no large bolt, all that energy is directed to accelerating a small cap, which essentially becomes a very good projectile. There is no receiver to contain the debris/projectile so it has a clear path to the shooter other than 2 small ears which also became projectiles. None of this is true with a proper 50 BMG design from M99 to M107 Video says it was likely 85ksi. The design clearly needs to be enhanced but if it was built to handle 110ksi (2x safety factor) it would have been able to handle that load without grenading and sending lethal fragments into the operator as happened here. Some damage yes, but not a catastrophic failure as demonstrated here. 50 caliber is an entirely different energy category from pistol and rifle calibers and should be treated as such. |
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That was essentially a pipe bomb going off next to his face and it blew the cap off.
You can see on the big cannons how overbuilt the threads & thread profile is Vs a straight thread with thin cross section. I was not aware of a screw capped .50 bmg rifle but I would rather have anything with thicker cross section and material Vs a cap and straight threads. Even a expanded Ruger #1 or falling block design has more material / surface contact area. Not his time to go and VERY lucky. |
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Wow glad he is OK. Note to self, don't use old iffy 50 BMG ammo.
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I’m surprised a gun with a .50bmg firing in your face only has a 1.5x factor of safety.
55ksi spec vs 85ksi threads. Plus thy thread engagement length is only like 1/2D of those threads. |
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Quoted: Video says it was likely 85ksi. The design clearly needs to be enhanced but if it was built to handle 110ksi (2x safety factor) it would have been able to handle that load without grenading and sending lethal fragments into the operator as happened here. Some damage yes, but not a catastrophic failure as demonstrated here. 50 caliber is an entirely different energy category from pistol and rifle calibers and should be treated as such. View Quote No, vid says 85ksi is needed to shear the cap. That means it was well above > 85 given the failure we see here. Duh. |
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Quoted: This one detonated in the magazine. The guy shooting said it was like having his hand crushed with a hammer. He was fine. https://photos.smugmug.com/Shooting/Organized-Gatherings/Upcoming-2014-APRC-Machinegun/i-j9WjKZP/0/cb25d605/L/20140517-GUNS3062-L.jpg View Quote Sounds like someone was using spotter rounds in a semi. |
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No way I’d have stepped behind that thing a fired it, ever.
Glad the guys ok Also, if you suddenly hit 1.5’ from poa, you might want to hit the brakes |
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