... The Kaboom - Sorta looks like the 50BMG barrel's thread's held, and the cap left all it's threads inside the barrel's threads when the cap ripped off and launched 🤷
1,973 likestexas_freight_train_8928 Sorry I just noticed the comments 😅 I should read the comments with a little more detail next time. 🤣
- laruetactical @bigcountry4030 ... Don't sweat it. These things go kinda fast and IG isn't always easy to follow. 3 likes
patriotvalley Did that barrel tenon only have ~4 threads engaged in the extension? 5 likes
- laruetactical @patriotvalley ... Well, yep. 1 like
- northwestdefense @patriotvalley but it was on tight. 1 like
- patriotvalley @laruetactical I just wanted to make sure it was indeed what I thought it was. When I saw the video I thought "uh oh another Serbu" but the victim said the ammo was tampered with. I'm not convinced the ammo was the culprit. Especially after this picture 1 like
jjc155 😮
angrygingertx Personally, even before this happened, I was sketchy about cheap 50 BMGs, now I'll not get within 50 yards of one. If it doesn't say Barret, McMillan, or Machine Gun, Heavy, M2 on the side of it I'll pass. The comment about idiots tumbling live rounds and turning powder that may have been little rods into dust is very interesting and sounds plausible too. I'm still not fing with cheap 50's ever. 1 like
- angrygingertx @angrygingertx and it's odd to me that the threads would shear. I know it's comparing apples to onions, but oil drilling thread connections that might be torqued to 30,000 lbs also have an over pull rating of sometimes 1,000,000 lbs. Seems like a few threads being hand tightened is sketchy as hell.
mr1bryce1 Shoulder fired pipe bomb.
pgiinc he will never shot one again I bet you on that
joshin_it_all I worked at Barrett in the range & shot a lot of the rifles before anyone else. All the ammo was hand loaded on site so I didn't worry about over pressure. I do wonder how a Barrett would hold up in a situation like this 🤷
the1911guy I wonder how he would have faired if it had happened with something like an Armalite/Barrett/AI/Cadex. The Serbu rifles that I have handled never gave me the same confidence that something like the AR50a1 did.
td3377 The fact there is only 4 threads engaged is alarming. Isn't there some sort of ratio of thread diameter vs. threads per inch?
- yam_yam_walsall @td3377 the rule of thumb for fasteners is the fasteners diameter in material thickness... but that's for mounting things to steel. Engineered fasteners have different calculations that are way above me.
abible17 That video was NUTS! He is very lucky! 1 like
willsmashu Surbu makes shit guns.
heyyy_ryan Aren't guns typically designed to have methods of dealing with bad rounds? Semiautos typically send the pressure into the magazine well blowing up the magazine. Bolt guns typically have little pressure relief holes near the locking surfaces in the receiver. What does this screw cap design have?
robert.swope That cap transferred most of its energy into those tabs when it sheared them off. That cap broke a few face bones, but those tabs took his hat back 10ft and cut his jugular and deflated a lung. His survival from that situation was a series of very lucky events.
back_for_tha_first_time Glad KB was able to walk away
multicam_usa I wonder if locking lugs would've held up better
lakepark_walley Nowhere near enough threads, very poor design.
dirk.t77 Just watched it. Feel terrible for Scott, what a champ tho!! 1 like
__narddog__ Looking at the first threads all the way on the left of the pic makes it look like it happened as Scott described, that the cap sheared off the threads from the barrel
able.rodriguez Glad everybody is ok, but come on some engineer made and educated guess to how the threads would hold up.
disner1 @laruetactical I see it the other way. Looks like the cap is fine and the barrel threads got wiped off. To me it looks like the 2 threads that remain are taller than the ones that are smeared off. 1 like
- laruetactical @disner1 ... Yep, I saw the same after scaring up my glasses. 🤓
merc321_ The powder used in SLAP is also notorious for rapidly degrading and becoming way more volatile. SLAP doing this isn't that uncommon, but most of the time it's shot in the proper weapon systems, GAU 19 and M2, and when they go it's not that big of a deal. The other issue is plastic sabot degradation, which can allow the projectile to get seated further back then it should spiking the pressure. Or this was someone's pissing hot hand loads, who knows.
The serbu RN50 doesn't have any other safety mechanisms other than the breach, so this was kind of a recipe for disaster. They could've also made it stronger by having the threads inside the breach as opposed to outside. Overall this was not a well thought out firearm since it has none of the safety mechanisms that have become common in the last century. 2 likes
kalohao That was crazy. He's a tough dude. The real deal. 🙌 1 like
jtfpeterson That looks like when a suppressor, muzzle brake, flash suppressor, or muzzle cap shoots off of the barrel. Pretty obvious.
tx4guns I talked to a very experienced gun collector and pyrotechnic engineer on this failure last night. He said that these surplus rounds are often tumble polished to make them shiny, and the powder inside the case can get pulverized in the process, completely changing the burn rate of the powder. That faster burn rate shows up in the results you see in the video. 7 likes
- laruetactical @tx4guns ... That was exactly my thought ... pulverized powder in the case, but I couldn't think of a decent reason to tumble a live round. 6 likes
- dmr_llc @laruetactical no reason to but people do it. 1 like
- handloadsandholdovers @tx4guns the polymer sabot should show some indication of that I would think 1 like
freedom_lover8080 Great call!!! Your the 1st to mention that.👏
robrebel7.62 I never liked the idea of putting my face behind a screw cap 50BMG. 4 likes
antoniolaserant That was the scariest thing I ever seen
greasemonkey529 Looks like a cross thread to me
- laruetactical @greasemonkey529 ... It screwed on pretty easily in video ... he didn't have to fight it. 2 likes
tactical_66 Gnarly video. He sure was quick to blame the ammo and not potential failures of the rifle. The manufacturer must be sh!t!ng his pants. A guy was almost killed by the failure.
texas_freight_train_8928 Is this the 50 that almost killed Scott
- laruetactical @bigcountry4030 ... Yes 1 like
red_dirt_cyclist This is the reason I never bought or fired one of these .50 cal rifles... I've seen M2 BMGs KB and it's nasty, even when surrounded with all that steel! This guy is extremely lucky! He easily could have been DRT! Glad he's OK...
- laruetactical @red_dirt_cyclist ... What do you figure caused the M2 kabooms you witnessed ?
- red_dirt_cyclist @laruetactical Head Space not set correctly by inattentive PFCs... 1 like
seanklk Wrong headspzace and timing??
- laruetactical @seanklk ... I've not held one of those rifles in my hands, does that cap screw on until you pin the round to the bottom of the chamber ? Or does it bottom out on a shoulder, setting the headspace ? 1 like
ballistic_addiction He was lucky to be alive after that one. 🙏
bullettrail Curious as to why the casing wasn't shown in the aftermath. Based off of how the threads looks, my guess is the cap was not on all the way. Improper head space and the round not being seated fully in the chamber is 100% chance of raptured casing resulting in a malfunction like this. Happens all the time in M2's when headspace is not checked properly before a live shoot. Bottom of casing will explode and have seen it destroy M2 feed tray covers and bolts everything internal on such a big heavy gun. Also SLAP rounds were never designed for a rifle with a muzzle break especially a light and small rifle like that. Specifically designed for 50 Cal Machine Guns. 5 likes
- culpepper_war_room @bullettrail if you watch the video he explains a lot. The cap must be on all the way for the barrel to close onto the lower receiver. The tabs would stop it from closing if the cap is not one 100%. The kaboom reminds me of an overcharged casing.
- bullettrail @culpepper_war_room watched the video, go no go gauges for all M2 machine guns are just a super small fraction of an inch in terms of the gun running or the gun having a catastrophic failure. Even if the cap was just a smidge not tight enough it might have been able to close but still left the smallest amount of room for the casing to rupture at the end. Hence the burn pattern at the end of the barrel. It takes just a small amount of room for a casing to rupture and explode. I've seen many 50cal machine guns go down just because the smallest amount of room is available for the casing to rupture. Just because someone says they did everything right doesn't mean the weapon is not to blame.
- culpepper_war_room @bullettrail i completely understand head spacing, specially on big boys. Ive had a kaboom myself, overcharged case. To get 85k psi from a 50, you need some high speed powder, im leaning more towards the tampered round with overcharge fast powder than a smidge lose cap. Specially after experiencing a kaboom first hand
- bullettrail @culpepper_war_room Possible however SLAP rounds are a struggle to take apart and put together.
- culpepper_war_room @bullettrail all it takes is one with a lose crimp
joewarner6336 Comparing this design with the threaded connection of any bolt action suggests the apparent deficiency. 1 like
amylynnwv Man I watched that video. WIIIIILD. Lucky man. 2 likes
devonwsorenson Moral of the story... slap rounds fuckin slap 5 likes
mrhaaaaas Whomever made the safety glasses, they worked well. 😮 8 likes
- jaylaroux @mrhaaaaas the only thing that performed as expected.
- pi.stacheo @mrhaaaaas those ratings on safety glasses are important.
culpepper_war_room The Lord is not done with him yey 1 like
missionjoker Damn
laruetactical ... Glad Scott's dad got the great video !! 30 likes
- aleex_el_cuh1209 @laruetactical glad he's okay 2 likes
- laruetactical @aleex_el_cuh1209 ... He is way more than okay ... he's back to work and already making us great after-action videos. The man's a beast !! 7 likes
- fit2practice @laruetactical How did his dad know to put a thumb inside the neck like that? Prior military or police? 1 like
- _jake_keller_ @fit2practice Scott has a prior law enforcement background 2 likes
- fit2practice @_jake_keller_ So grateful he was trained, thanks for the response! 1 like
- john_r_priest @_jake_keller_ I think both of them do, the way they acted and left in under a minute leads me to think they both have LEO or militarily. We know Kentucky does but I imagine his dad does as well. 1 like
merpaholic The barrel weighs like 25 pounds (I think he mentioned in the video). Thing flew like it was made of styrofoam. He definitely got lucky as hell with that, probably safe to say he's putting the SLAP rounds away for a long while. 1 like
- laruetactical @auzball ... His dad saw it in real-time and it must'a looked like a magic trick. Now ya see it, now ya don't. 6 likes
david_shepardn7 They look equally sheared off
taylor.pics1 Uhh, not tryna be that guy, but you can clearly see the barrel threads have been sent to oblivion 10 likes
- conservativedna @laruetactical *clearly taller 1 like
- laruetactical @conservativedna ... Yeah, I put on my glasses 🤓 7 likes
- legitimate.businessman @taylor.pics1 man I had to look twice but you're right. Good eye!
craigs_guns.n.grub Yep, definitely looks that way. I'm curious what alloy Mr. Serbu is using for the caps, and what thermal treatment they get. This would be a very interesting failure analysis to be part of. 2 likes
- emmitt.s_ @craigs_guns.n.grub check out @kentuckyballistics 1 like
- craigs_guns.n.grub @nicholas_e13 I have. I've seen the video a couple times now. I'd just really like to get some of the parts into an SEM and look at the failure modes. I know Mark Serbu said that it would take 85,000psi to shear those threads, but if the cap is against the lugs that sheared off, the round had to be an even higher pressure. Unless the rifle began to fail after the 2nd SLAP round that there obviously was something wrong with as well. 1 like
houndz308 @laruetactical and @ everyone else... DID YOU NOT WATCH THE VIDEO? He goes over it all.... 4 likes
- robert_vosburg @houndz308 sounds like they didn't
- laruetactical @houndz308 ... Where do you think I got the pic of the barrel threads? 2 likes
dsarmsinc The threads seem to be filled with the material from the cap threads must have been a crazy over charged .50bmg 13 likes
- fischermotorsports @dsarmsinc .
Or threads were already fatigued and at end of life.
- wysong.brian @fischermotorsports they would show signs of it.
- laruetactical @fischermotorsports ... Yep, proof tested and then some. 2 likes
polinger_boogeyman_customs No, barrel threads went bye bye 5 likes
the_evan_principle 85,000lbs of chamber pressure and the Sorba has a max rating of 55,000? That's what I read anyhow. 2 likes
- the_evan_principle @danquarius_washington crazy man. Serious. Dude kept his head on straight (pun maybe?) and jammed his thumb in his neck and kept it there while he drove himself to the ER. Talk about badass 7 likes
- daniel_a_urena @the_evan_principle he didn't his dad drove him there 2 likes
- the_evan_principle @daniel_a_urena possibly? So...he plugged his thumb in his neck while someone else drove him. Semantics maybe? Doesn't make him less badass. 3 likes
- daniel_a_urena @the_evan_principle not saying he isn't badass just wanna make sure people know the correct story, gnarly story overall I watched the whole video 2 likes
- the_evan_principle @daniel_a_urena yeah man, gotcha! What's nuts is I saw the guy in the hospital all over the Internet, then saw the video. I think it's even worse when you know what happens. Gave me the chills. 2 likes
fitty_actual @laruetactical yeah, I agree with @taylor.pics1 and you both. The top half of the external threads and internal threads both sheared.
- laruetactical @fitty_actual ... Do you reckon the cap is actually undamaged ? 1 like
treyfromflorida He's lucky. Even tho his injuries are pretty gnarly 5 likes
- laruetactical @treyfromflorida ... Jeeminy, no pun but Scott's all kinds of banged up 😳 5 likes
g_buku Watched his video of what happened, dude is lucky to be alive taking a hunk of steel to the face with 85k psi of force. 17 likes
- laruetactical @g_buku ... Where did Serbu come up with that 85K psi number? 6 likes
- jmflor1no @laruetactical I'm guessing, that in their testing a number greater than 50k psi blew up their test gun. I'm sure Scott showed them photos and they likely estimated based off their experience with product development failures 3 likes
- jaylaroux @laruetactical I did see the 85k psi on another post about it, but didn't see how they came to that number. Don't even know how you could measure it tbh 2 likes
- fischermotorsports @laruetactical .
So what's the likelihood of it not being an over pressure issue but a thread fatigue issue (threads already cracking / failing and near end of life) and this was the round that simply finished them off? 2 likes
- g_buku @laruetactical no idea. According to the video "Mark Serbu said that normal pressures are 55kpsi and for the cap to shear off is over 85k psi". 1 like
- john_r_priest @fischermotorsports @iraqveteran8888_official made a post of what he thinks happened and it seems to be the most likely that I've seen. While we dont know what all the events that caused this are, thank god for safety glasses.
- fischermotorsports @john_r_priest .
Agree, good for eye pro and him making it through it.👍 .
Yes, saw the video... I still think the lessons to be learned from good analysis of what actually occurred are important. Not saying this is the case here, more needs to be known, but in my profession people draw incorrect conclusions all the time and everything should be questioned. .
We know that thread failure occurred. The real question is why and much has been discussed on this that are all valid points. Were the threads cut or rolled? Cut leaves stress riser profiles that over time are more prone to fatigue cracking and failure. Thread engagement has been brought up, also a good and valid point, the target engagement for threads are typically 1D at minimum to 2D for maximum. That cap design clearly doesn't meet that. Seems like some good lessons here for all in the industry. 1 like
- john_r_priest @fischermotorsports mark serbu just put out a video. He is getting the rifle and ammo soon, and is gonna do a full analysis and video. Looking forward to it.
- fischermotorsports @john_r_priest .
Yea, agree. That will be interesting. 1 like
the_peoples_airsoft You are looking, at what we call in the AFA world, plastic deformation
tort_life_ Sent you a message! 1 like
- all4freedom @tort_life_ you leave Mark alone he has work and shooting to do.
rhodie333 Hot rounds are dangerous. 1 like
csolstice032018 I understand the cause but there seem to be multiple points of failure. The ear that sheared off the lower they dug out of his lung sheared completely off. No bueno. 1 like
- laruetactical @csolstice032018 ... That was surprising. Seems as if the cap should have been deflected somewhat upwards. Almost lucky it did shear off or the cap might have hit Scott smackdab in the forehead. 3 likes
- ryandavis2013 @laruetactical The cap hit him in the eye, didn't it though? That's how he broke his orbital and nose.
- laruetactical @ryandavis2013 ... Yep, but had that cap deflected up and hit him square in the forehead 😳 I have no idea which is worse, but he survived where it did hit, so I'd take that preferred outcome. 1 like
- csolstice032018 @laruetactical He's a lucky man he got to keep his head for sure! Top side of grass, talking and walking is always preferred!
tacflow_lang SLAP 50 BMG rounds are not designed to be fired in light fifty's for a reason. The plastic sabot around the projectile can fail to completely exit and potentially gum up the muzzle brake device causing an obstruction for the next projectile fired. Is there also the possibility of increased psi with the SLAP round fired in the light fifty, of course that is why they are not designed to be fired in these rifles. SLAP rounds have muzzle velocities around 4000 FPS and are intended to be fired from the M2. Do the math! 18 likes
- laruetactical @tacflow_lang ... 4,000 fps ?! 🤓 < - that's my jealous face 3 likes
- tacflow_lang @laruetactical Mark, I got a HSM 127 Light Armor Penetrator round out of your OBR 20" at 3103 FPS.
- hovistodd @tacflow_lang proving that SLAP rounds can screw your day up at ether end. 1 like
- cle112 @tacflow_lang I'm curious as to how a possible barrel obstruction was still present after two non-SLAP rounds were put thru before the final round. The sequence was SLAP (normal muzzle flash) SLAP 2 (large muzzle flash) 50 BMG, then a second 50 BMG that was caught by the hydrant and lastly the SLAP that exploded. Regardless of cap, firearm appropriateness , round failure, barrel obstruction, or combination of I'm just glad Scott is alright. The lesson more then anything to take from this. When trying some non standard rounds or non traditional shooting, have someone with you. 3 likes
- wille275 @tacflow_lang big facts! Had slap rounds demo two M2's in my life and always had problems with them! Stopped using completely.
- sirius_sirius @tacflow_lang yup he's firing unknown slap rounds through a brake. not the brightest idea
wcgrandi Not familiar with this rig whatsoever... if the threads failed via shear (as in they theoretically allowed the chamber/barrel to move in opposite directions), why are there still a few threads intact? Could it have not been fully threaded/torqued? Or is that because the barrel expanded, fragmented, and didn't have a chance to grab the last few threads? 1 like
- culpepper_war_room @wcgrandi the threads dont get full engagement near the bottom which is why some remain. And the gun wouldnt close without the cap being on all the way. 1 like
- wcgrandi @culpepper_war_room roger, thank you. Was curious. Tremendous force; "ain't nuttin' ta fuqwid", as we say in Florida
- culpepper_war_room @wcgrandi true story, native floridian myself
pnhurst Dumbest breech design ever. And on a 50BMG no less. 7 likes
- laruetactical @pnhurst ... Does the cap get tightened with a torque wrench before shooting ? 1 like
- jabon_clamshell @laruetactical Nope. By hand
- senpai_32918 @laruetactical no by hand and the barrel won't lock to the lower unless the cap is screwed on all the way is what he said
- bullettrail @senpai_32918 he also said that SLAP rounds are no longer produced which is completely incorrect. A lot of miss information in the video. 2 likes
- tractoroper8tor @laruetactical no
- laruetactical @senpai_32918 ... Wouldn't that aspect of "not closing unless the cap is on" be a sorta/kinda rough go-nogo ? 5 likes
- thirtythree_three @pnhurst This (what you said) is what needs to be the takeaway. People are focused on the ammo, but there are at least 4 50BMG's (and I'm not talking about the Barrett M107A1s or the M82A1s, either) that could have prevented a trip to the hospital altogether. The AI has excess pressure blast ports specifically for such scenarios. The design was terrible and Serbu should fee pretty badly about this.
- makerinarms @bullettrail I definitely saw belts of them in Afghanistan. Never knew the name but it was a very cool and mean looking round
mcdrinkle That dude used up all his luck on that one. 23 likes
- laruetactical @mcdrinkle ... Okay, that was funny and you're right. 9 likes
- bigballzinhtown @mcdrinkle Hope he stopped on the way to the ER to buy a lotto ticket
- mcdrinkle @bigballzinhtown itd be a waste for him to ever gamble again. The piece of the receiver that missed his brain and the one that went into his neck and he survived were the lottery he won. 1 like
- mcdrinkle @laruetactical this video makes me cringe. I can't believe he made it. 1 like