Saw this pop up, didn't who all has seen it.

YouTube

TLDR: Bad SLAP round blows up Serbu RN-50, severely injures Scott (Kentucky Ballistics)

Makes you question the specialty rounds in circulation. When we know there's fake Roufuss being sold, it makes you wonder about the other rounds that are floating around. Who actually loaded them?

dupe

Wow!
He's very lucky to be alive!

Just saw it on a FB group and came to post.
And I did not see it posted in this forum before.
I'm thinking that part of the Sabot(s) blocked the brake ports causing the pressure increase.
SLAP Ammo Is Not meant to be shot through a brake equipped rifle.

Do you think he had a bore obstruction?

how rugged is a course thread cap like that?

Wasn't likely a bore obstruction.

The round just prior to boom, was a non-sabot AP.  I  know very little about SLAP rounds and any chamber or brake requirements, but based on where the rifle separated, the chamber pressure was massive.

From my (limited) experience, bore obstructions towards the end of a barrel usually pop or bulge the barrel at that location.  It's certainly possible that SLAP round had been tampered with and an incorrect powder loaded.

I didn't know they required a special chamber. I though they where to be shot though standard M-2. I know you can't use a break with them. Hmm learned something new today.

Something that's always really scared me with these high dollar slap rounds is. Back in the day I bought a whole bag of like 100 of the sabots and a handful of the cores. I am sure I am not the only one.... But I have never seen load data for them. And they are a lot lighter than a normal 50 rd. So I could see someone using a faster powder for them. aka God only knows who loaded them and what they where loaded with..... That is a scary thought. I still don't know what to do with what I have. lol I would love to hear some load data... or what the load SHOULD be.

I think what happened was a combo of 2 maybe 3 things.

1. See above, god knows what was in that round.
2. That gun was a royal some such design (Mr pipe gun extraordinaire), that design clearly wasn't far from it's pipe gun roots. In the photos you can see that it only had 4 threads engaged that stripped out holding that cap on. I think the design was NOT good at handling escaping gas, and containing parts in the event of a failure. My hunch that round would have blown up a M99 but that the design of the gun would have prevented the shooter from almost getting killed. Shoot I think if it was shot in a Bohica (we are setting the bar real low hear in my mind, and I sometimes shoot a Bohica and wonder if I am taking my life in my hands doing it). I think it would have done a better job of containing that. I think in that case, shooter would have ended up with a shoulder wound from the bolt. BUT I question if it would have sheared the lugs off, they are HUGE compared to the threads on that RN50.
3. The break on that gun (but I think if it was the sabot getting caught in the break it would just be the accuracy problem that he was seeing, and at worse split the barrel and grenade the break). Or this thing I am hearing about requiring a special chamber, and that could be it. I just don't know anything about that. It's new news to me. Scary and might be the whole issue. BUT I don't know anything about it.

Oh and side note... lol something about this makes me want to figure out a load for the cores I have, and use the rest of the sabots with 30cal black tip... Like gee wonder what that would do. Moth to flame and all. But after watching that video again, they are probably better left in my little ammo display as inert rds.

^ you're not the first to comment on the extreme lack of threads on the cap interface.

Hoooooolllllllyyyyyy CRAP!

I saw one YouTube video where the shooter said the Serbu was designed to accept the SLAP rounds. It might have been from "Going Ballistic"

Dam those look a LOT different from the ones I have.... Mine do fit a .30 cal projo, but they are tight. They fit the slap cores better. They have a blue tint to them and NO driving cup, like the ones you showed. Off to find one and take a pic. Sounds like I bought some fakes back in the 90's....

lol after looking at mine... Now I am wondering if the sabots are a knockoff and the cores are 20mm slap cores... lol eeekkkkk

Attached File

Is this being discussed elsewhere? I'm curious as to further speculation on probable causes

There is a 6 page thread in General Discussion

Tony

https://www.ar15.com/forums/general/Kentucky-Ballistics-50bmg-exploded/5-2448452/

Royal Nonesuchs terrible design is at fault for this.

Say whatever you want contrary, but its the truth.
He’s posted his unsafe venezuela-tier designs for years and its always memed into maintstream by his fanbois. He builds slamfire shotguns out of plumbing supplies...why would you want to be anywhere near anything he says can handle .50 BMG when it's firing?

The RN-50 design is terrible, and acted like a pipebomb. Any other design has safety measures to aid in not killing the user in the event of problems. This does not.

Guns should be designed to fail as safely as possible - perhaps with some metal enclosure to catch fragmentation, or vent holes to bleed pressure from the chamber in the event of severely overpressure ammunition, or maybe some sort of extra lug to keep the breach or bolt from flying at the user.

By contrast the e-celeb self-aggrandizement project, is designed to shoot it's breechblock through your fucking face in the event of catastrophic failure.

I've always questioned his use of sabot rounds in a rifle with a brake. I've always read that those rounds shouldn't be shot out of a gun with a brake.

Should have bought an AR-50…

First offl, shooting questionable rounds is a nogo  Second is shooting any sabot round with a brake.  I would not do that with my fifty because I hate hospitals.

Yep. I posted in the 2 GD threads about the blow up.

that was my understanding, for accuracy reasons at least, diff barrel/chamber required - I almost bought a used EDM years ago with a second barrel for SLAP rounds

The GD threads on this were maddening. Buncha dingbats and Monday morning engineers making the dumbest assertions. Makes ne question if they have clue what's going on in their ar15 or if the just understand "pull small lever thing, make loud noise."

Ok. That was pretty funny. But true.

Mark Serbu finally talked about it. Key points (for what it's worth):

* This is the first RN-50 to blow up.
* It's not a Royal Nonsuch design. Serbu claims all credit for its design. I guess any claims that Royal Nonsuch (I have no idea who that is, btw) were a joke that got out of hand.
* He's getting Scott's rifle plus his SLAP rounds to investigate, and he's going to start blowing up some of his own guns to see what conditions are necessary to cause such a failure.

Except that the gun in question isn't even a Royal Nonesuch design, it's a Mark Serbu design.

Will be interesting when the test results are released.
Especially the ammo and what type of and the amount of powder used.

When the RN-50 came out, I was one of the few to reject it immediately for its apparent lack of redundant strength.  I like Mark and everything he has done and admire his accomplishments.  However, the RN -50 was due to have this happen just because of the design.  There is NO WAY I would put my face behind a fifty receiver contained only by two vertical pillars and a cap and thread setup.  Before I get the hate...I realize that the ammo was probably the issue but I highly doubt the same ammo in a conventional bolt rifle, say Barrett 99/95 or AR-50, would have had the same life or death situation play out.

The failure mode of firearms is something I try to be cognizant of. Not wary but aware. I appreciate how AR15s and M82s split at the receivers, blow the gasses down the mag well, and send the bolt back into a contained space. Bolt guns and things like the RN-50 that are more cannon than rifle are more robust but damn... Nothing but soft flesh between a ballistic bolt and your arteries if the lugs or threads strip.

Do you have a link please?

Here's the video from Serbu.

Thank You, off to watch it.
Very Informative.
Especially the pics comparing the ammo used vs. an authentic slap round.

Yeah, I think Scott was shooting counterfeit SLAP ammo.  No surprise that there is such out there, given the cost per round of the real stuff.  I can't wait to see what Mark discovers regarding that ammo.

Good videos and makes a lot of since. I also think it was the ammo and it would have blown up any gun it was put into even a M-2 most likely. Scary stuff. I am SHOCKED at the about of scammers and counterfeits I am seeing in the 50cal arena right now. GB seems to be awash with them, so many fake adds and out right scams it's scary. Careful out there guys. To me this is just NUTS. That people would do carp like this and could have killed someone just to make a quick buck on some scamming fake ammo. Sad. I hope they can track down the guy selling this crap, and who all he's sold it to... It's out there boys. Tick tock till the next Kboom.

Mark has stated multiple times that RN came to him with the idea, and mark took and ran with it.

I stand by my original statement. Dogshit design at fault for this.

Quit being a fucking poor, and risking your shit buying a poverty tier 50bmg.

I think it is insane to fire a 50 BMG rifle that has no traditional battery of a bolt and lug locking system.  To this day, I can't believe how many seasoned 50 guys had no problem with the RN-50 design.  If there was a design of, say, an RN 556...for the financially challenged, that may be a bit safer.

I somewhat agree with you about the design, however it appears that it was the result of a Severe chamber pressure.
Having said that, I wouldn't shoot on or own one even if it was free.
I'm happy with my Steyr HS-50 and SHTF 18" 5 shot upper.
Has a dedicated single shot lower mfg. by Stubborn Mule.
Lower was about 300 bucks but the package looks great.

Bigger thread on the topic

@ibuyre2 @Alderleet That was my main takeaway. Regardless of what caused the kaboom, the RN50 doesn't seem to be designed to fail "safely."  By that I mean many gun designs incorporate features to reduce the chances of severe injury or death on failure.

Kentucky Ballistics said that in one of the first videos he posted.  Something about the stock RN50 isn't supposed to shoot slap rounds, but his RN50 was supposed to have a different barrel that could accept slap rounds.

https://www.youtube.com/watch?v=tpp4SdE1MUk&t=305s

Mark put out a video going over some of the damage on the rifle.

Yup.


Thanks to you and others that is info I have long stored in my head for years.

It’s already been clarified his rifle had the correct chamber.

Are you saying that the use of a muzzle brake in combination with Slap rounds is what caused the rifle to explode in this manner?

Thanks for the update, I forgot about this.
Really interested in the type and amount of powder that was used.

@50_Shooter

1) shooting SLAP with a brake is a bad thing, but does not cause the gun to blow up like this. All sorts of nasty down range, but not a dangerous over pressure.

2) shooter says previous round was a regular round, NOT SLAP. Round impacted target. No possibility of an obstruction.
Having a short chamber will cause overpressure. I'm not sure by how much, given the sabot is plastic. Would be interesting to test.

3) correct about the rounds lacking a factory crimp, and short of a lab test, no way to know what powder.

I do wonder what Mark is gonna do. Fill a slap round full of bullseye with a pressure transducer?