More on Kentucky Ballistics - Serbu
- Thread starter Jim Watson
- Start date
- Status
DeepSouth
Random Guy
If he said that I don’t remember it, which is certainly possible.. my memory is not the best
Well, I'm not. Kabooms happen with every design. The fact some kind of "event" occurred was most likely was not due to the rifle's design. What happened after most likely was.
When Paul Mauser had an eye put out by one of his rifles he paid great attention to improving the safety of later designs, vent holes, gas flanges, safety lugs, etc. Some designs are safer than others. All modern designs are "safe" when nothing goes wrong, it's what happens when something does go wrong that makes the difference.
daniel craig
Member
- Joined
- Dec 23, 2009
- Messages
- 2,839
When I did some research on SLAP and what they were designed for, that was really all I needed to know. When the shooter said the origin of the ammo he was shooting was unknown that clinched for me. Every thing after that was irrelevant to me.
Perhaps that’s flawed logic but it’s good enough for me. I put this 100% on the shooter.
Perhaps that’s flawed logic but it’s good enough for me. I put this 100% on the shooter.
Jim Watson
Member
Jim Watson
Member
Ought to be able to track from
"C&O T-1 steam locomotive, number 3020, after a boiler explosion in 1943. Located near Chillicothe, Ross County, Ohio"
And now back to scheduled programming of doubtful ammo in a doubtful gun.
"C&O T-1 steam locomotive, number 3020, after a boiler explosion in 1943. Located near Chillicothe, Ross County, Ohio"
And now back to scheduled programming of doubtful ammo in a doubtful gun.
mgmorden
Member
Knowing what caused the event can help determine the severity of it. Just like you can die in the safest car in the world if an accident is bad enough, so can the best designed gun in the world turn itself into a lethal pipe bomb with sufficient pressure.
I'm not saying that the RN-50 is the safest gun in the world by any stretch of the imagination, just that not all kabooms are created equal. Knowing just how big of a boom we're talking about is important in determining if the rifle is lacking in safety features or just was presented with a hopeless scenario from the beginning.
MachIVshooter
Member
Perhaps you'll have better luck getting that point across to some of our members than I did. There seems to be a few with an expectation of a firearm to pull double duty as a bomb disposal unit, that it's a faulty design if the shooter is injured, regardless of the magnitude of the event.
He can call them anything he wants, but there's no debate about how they behaved in this failure. Even if that's what he intended them to be, if they turn out to be the most dangerous parts on the gun in the event of a failure, they don't meet a reasonable definition of "failsafe". As a result, I have a hard time calling them failsafes, and they certainly weren't failsafes in this situation. You clearly don't like those two statements, but neither one is really debatable, nor is either one speculation.
Now we're focusing on what should have been done during the design process vs. looking at the outcome of a negative event.
I agree that a design needs to start from the ground up, from a solid understanding of the material properties, potential stresses, etc. Which is why I was surprised that Serbu didn't have the proper number to quote initially with regards to the barrel threads shearing and even now seems to be relying on someone else's calculations for those numbers.
Definitely correct.
But this gun didn't "turn pipe bomb" The failure was, in one sense, very controlled. Only one part (barrel threads) failed sending the breech cap directly towards the shooter with tremendous force. Enough force to shear off two steel pieces which were, at least in part, apparently placed there in anticipation of just such a failure to protect the shooter. Those two pieces were then propelled directly towards the shooter, also with tremendous force. And they sheared off without even deflecting the end cap sufficiently to prevent it from hitting the shooter.
I definitely agree that there can be point where the stresses get way too high, all bets are off and things just go to pieces in a completely uncontrolled fashion. If you put high explosives into the breech, the brisance is going to be so high that any part or every part of the intended containment could fail. Then it's hard to make any kind of statement about the design. That's a very different situation from this event.
Here's what bothers me about this.
The gun had a single point failure that the designer seems to have anticipated as being a possibility.
The designer claims to have added a design feature to make that single point failure safe for the shooter and yet that feature did not work as intended in this event.
There's a lot of focus on the fact that it's impossible to make a design that can't be blown up. That is entirely true. There's a practical upper limit on strength. But there's no need to make a design that can't be blown up, it's only necessary to make a design that fails in such a way that it doesn't kill the user. That can actually be done by making the gun less strong--just less strong in the right places. So if it takes 160,000psi to blow the endcap off the back of the gun, design the top of the chamber so that it fails at 120,000psi and vents the pressure directly upwards. So now a weaker design, one that fails 40,000psi earlier, is actually safer for the shooter.
But in order to do that, you have to know at what pressure the end cap will come off the back of the gun. You have to know that while you're designing the gun, not after it's blown up and someone else does the calculation for you. You have to know how to weaken the chamber, and how much to weaken it in order to get it to fail at the pressure you want it to. Without weakening it so much that the gun fails in normal use with normal ammunition even after thousands of rounds fired.
The ears that broke off of the receiver are not there as a fail safe measure. Those are there to be sure that the end cap is on correctly.
I don't know how everyone got this mixed up and keeps repeating it. It was pointed out in the original video from KB and I think Mark repeated it.
Same goes about the original amount of pressures. Mark had thrown out a number for KB and Scott talked about it on the original video. Mark updated it kind of on his initial video about the incident.
Mark said in the last video that he's going to make a separate video to clear up some of the mistakes that have been going around.
I don't know how everyone got this mixed up and keeps repeating it. It was pointed out in the original video from KB and I think Mark repeated it.
Same goes about the original amount of pressures. Mark had thrown out a number for KB and Scott talked about it on the original video. Mark updated it kind of on his initial video about the incident.
Mark said in the last video that he's going to make a separate video to clear up some of the mistakes that have been going around.
Guess I'm going to have to watch it again.
ETA: Guess I was mistaken and heard wrong but as it turns out, the ears are a secondary safety feature. I either read it on one of the multiple threads or heard it wrong on one of the videos.
Anyway, at least I know now for sure that its a safety feature. The original PSI numbers that were put out, something that Mark told Scott and said he was just throwing it out there. He said that he wishes he didn't because the number is actually closer to 161K PSI.
ETA: Guess I was mistaken and heard wrong but as it turns out, the ears are a secondary safety feature. I either read it on one of the multiple threads or heard it wrong on one of the videos.
Anyway, at least I know now for sure that its a safety feature. The original PSI numbers that were put out, something that Mark told Scott and said he was just throwing it out there. He said that he wishes he didn't because the number is actually closer to 161K PSI.
Last edited:
Good points. But let me point at what I consider the Elephant in the Room.
The American shooting community is heavily libertarian. That is, every shooter thinks himself the ultimate expert, knows everything, and does not want anyone telling him, or anyone else what to do. I would be curious to know what sort of product safety regulations are in affect for firearms. What mandated safety tests, what mandated endurance requirements, what mandated strength and safety factors? Does someone know? I did look up the CFR safety standards on fire extinguishers, and Federal law limits the stress levels on the cylinder walls. Maybe some of the smart people here can tell me what Federal, or State safety standards there are pertaining to the structure, structure lifetime, and to structural failure of firearms. I don’t think they exist, which is what the Shooting Community wants.
I am confident there is no American safety board anywhere, overseeing firearm design and manufacture, with regulatory power to imprison or fine. Europeans have proof houses. Every firearm made has to go to a proof house, be gauged and fired, and that includes sales between individuals. Regulators in Europe have centuries of experience with knuckleheads who think they know best, which is why the proof system in Germany (at least) demills defective & unsafe firearms. And I would ask those who are skeptical about this, just how would you prevent operational dangerous and defective firearms from being fired once they leave the proof house?
The US does not have a Proof House system, American shooters consider themselves the experts on safety. That is what you want, that is what you think, but understand, this is very Darwinian. If you the individual, are incapable of looking at a design, and deciding that it is too dangerous for yourself, then, what happens afterwards is all on you.
I have a bud who designed the locking mechanism on the Armalite AR50 rifle. I have handled his beastie, and the mechanism is massive, and well designed with considerations towards shooter safety. The MSRP on an AR50 is $3,985. https://www.armalite.com/SACItem.aspx?Item=50A1BGGG
The Serbu RN 50 is $1,259 https://serbu.com/rn-50/. It is obvious the designer and manufacturer of the Serbu rifle designed to a lower price point, and more or less, you get what you pay for. I would hope the Serbu rifle was designed to good material and structural standards, but I don’t know. I don’t know what standards Serbu followed. I don’t know if Serbu did any sort of testing, and, Serbu is not required to follow any standards or do any testing. And that's the way you want it. If you, the American shooting society want safety standards, the same sort of regulation that the car industry has to follow, then you have to demand it from your legislative representatives. And I am quite confident, given the libertarian attitudes in the American shooting society, you won’t. All you can really do is point out, after an accident, unsafe weapons, and hope that the bad publicity generated makes those weapons go away. Even then, such as on low number M1903 Springfields, you will always have deniers. So the unsafe weapons never really go away, until they all fail in the hands of unknowing shooter, and that takes time.
Which is what you want, given that you are the ultimate expert, know everything, and don’t want anyone telling you nothing.
Last edited:
American firearm manufacturers test their own firearms. They also know that they're going to be sued for a lot of money if someone gets seriously injured by one of their products.
Here's why none of this matters, if you reload who checks your ammo? If you buy reloads, remanufactured and or surplus, who checks it?
Now you load it into your RN-50 and get a kaboom! Who's to blame, Mark, Scott, the person that loaded it?
Mark is going to say, did you read the part in the owners manual about not shooting reloads, remanufactured ammo... no? Sorry but you created the problem by buying and shooting unknown ammo.
So what did the proof house do or would have done in this situation? If Mark had to submit a copy of the RN-50 for testing and it passed.... do you think people would still be saying the things they are about the design? Of which there are at least 1,400 out there and this is the only one that had a problem, that we know of.
I know that Mark uses proof loads to do testing with on his rifles. How do I know this? A good friend of mine loads the proof loads for him.
Here's why none of this matters, if you reload who checks your ammo? If you buy reloads, remanufactured and or surplus, who checks it?
Now you load it into your RN-50 and get a kaboom! Who's to blame, Mark, Scott, the person that loaded it?
Mark is going to say, did you read the part in the owners manual about not shooting reloads, remanufactured ammo... no? Sorry but you created the problem by buying and shooting unknown ammo.
So what did the proof house do or would have done in this situation? If Mark had to submit a copy of the RN-50 for testing and it passed.... do you think people would still be saying the things they are about the design? Of which there are at least 1,400 out there and this is the only one that had a problem, that we know of.
I know that Mark uses proof loads to do testing with on his rifles. How do I know this? A good friend of mine loads the proof loads for him.
mcb
Member
The closest the US firearms communality has to a regulatory body is is SAAMI. There are design and testing guide lines from SAAMI and most gun manufactures follow those guidelines and SAAMI members are suppose to. Not everything SAAMI publishes is available to the public on their website. There is a members only side to that website and considerable more information available then what they choose to add to the public domain. Some information is for members only.
https://saami.org/wp-content/uploads/2019/01/SAAMI-Z299.5-Abusive-Mishandling-Approved-3-14-2016.pdf
This document shows the abusive handling test procedure for ensuring a gun is safe to be dropped in likely scenarios. There are more similar documents covering a wider variety of safety checks on the member's side.
There is also the US military who publishes there own requirements for small arms. TOP-3-2-045 (http://everyspec.com/ARMY/Test-Operations-Procedure/TOP-3-2-045_32068/) is a great example and includes procedures for 3 different obstructed bore tests along with the military's version of the abusive mishandling like SAAMI above but much harder to pass. (SAAMI 4ft onto a hard rubber mat, US Mil 5ft onto concrete)
You are 100% correct. In the US, the care and feeding of their favorite thundersticks is on the owner. And dangerous reloads are common, and no one tests their surplus ammunition for pressure, as pressure gauges are uncommon.
I don’t know all the Proof House laws in Europe, but I do know that ammunition manufacturers in the UK have to submit their ammunition to Proof Houses for testing. So the ammunition on the market has at least been tested by an independent agency. I am sure Amerc would not have passed, given the number of kabooms that were reported with that ammunition. As to reloads and surplus ammunition, I don’t know if EU citizens are allowed to reload, or buy surplus ammunition. They might not.
We know reputable manufacturer’s will stand behind their products. I also am aware of manufacturers receiving blown up customer guns, which upon inspection, were fired with reloads. Even though the customer denies it.
However, a Proof House system would have created a barrier for shoddily built rifles, like the National Ordnance M1903A3’s which there are a number of blowups due to poor receiver castings. And one of the incarnations of Kimber, sold 308 Win rifles built around Swedish M96 actions. The 308 Win operates at pressures that are equal to, or above the proof pressures of Swedish 6.5 X 55 ammunition, and I have read reports of these Kimber rifles blowing their receiver rings. Kimber was going bankrupt, so they were shoveling shoddily made rifles out the door, and the guys at top maximized their salaries before the company went bust.
SAAMI does not have law enforcement powers, it is a voluntary organization created in part, I believe, to prevent any Government Body being created for the same purpose. Industry does this because Industry hates regulation, don't we all? I have read the history of SAAMI and a standardization body was needed and the creation of it was a good thing. But nothing SAAMI does, or does not do, is legally binding.
In so far as the military, the military creates specifications, and incidentally, Industry creates specifications and standards. There are literally thousands of standards and hundreds of standard organizations. I don't think this list is all inclusive https://en.wikipedia.org/wiki/List_of_technical_standard_organizations All these standard organizations fight turf wars, because turf means money. You as a customer can specify that a product meets this, or that standard, and if the seller agrees in a contract, it is legally binding. The seller can also "no bid" and inform the buyer to take a hike, or perform some unmentionable act with their anatomy.
That was one of the reasons the early M16's got into the ball powder problem. Pressure curve requirements for the early M16's were tighter than industry state of the art powder manufacturing could hold. I think it was Remington, but the powder maker had to make, lets say, ten powder lots, and then sample which ones met the pressure curve requirements, and use only those to reload 5.56 ammunition. The powder used was a stick powder, IMR4477. Of course, even if only two lots were acceptable for loading the ammunition, Remington charged the Government for all ten lots of powder. At some point the Government told Remington that it would guarantee that all powder lots met the pressure requirements, and Remington told the Government to go pound sand. That left the Army without a powder supplier. The Army then used M14 ball powder, which did not have a pressure curve appropriate for the M16, and good American boy's died in combat with jammed M16's in their hands. Incidentally, the Ordnance Department made sure to conduct acceptance tests of factory Colt M16's with the stick powder, because that kept Colt happy.
I suspect the average gun buyer will not bring enough money to the table to make S&W, Ruger, Remington, Winchester, agree to any specification language. Gun buyers buy on reputation.
Jim Watson
Member
They do reload. An Italian IDPA shooter told me so recently. I don't know if there is a surplus market.
Or or price, which is specifically where this problem came from, an economy model in a large caliber.
I will say this, Scott is a stand up guy for admitting what happened and making a video about it. He's also not blaming anyone either for what happened.
Mark doesn't have to say a thing either but he's made 3 videos so far. He's also looking into what happened to a firearm he made. When he posts the final video with an explanation of what happened, I hope it covers everything.
Personally, I think it will help if we get the whole story. That means it will take awhile, especially if the rounds in question are also investigated, which they should be.
Mark doesn't have to say a thing either but he's made 3 videos so far. He's also looking into what happened to a firearm he made. When he posts the final video with an explanation of what happened, I hope it covers everything.
Personally, I think it will help if we get the whole story. That means it will take awhile, especially if the rounds in question are also investigated, which they should be.
Jim Watson
Member
I agree with that. Usually a wrecked gun like that disappears into a swamp of "bad ammo" vs "weak gun" claims and nothing is ever made clear and public.
MachIVshooter
Member
It's not a matter of like or dislike. Again, I have no dog in this fight. I like Mark as a person, I think he makes some really neat stuff, and I wish him the best in his ventures, but the success or failure of his company has no impact on my life. Accuracy is important, though, so I addressed the assertion that the safety measure didn't exist. Whether or not they served their purpose is a separate question. And to that end, maybe they did. The energy that the cap expended taking those ears out and denting the frame they deflected it into was tremendous. If they hadn't been there, Scott's skull may have taken the full force of the cap, and looking at what it did to the ears and frame, I imagine that would have been instantly lethal.
At any rate, an air bag, safety cable, back-up parachute, etc failing doesn't negate it's existence. That's my point. Saying "I have a hard time calling it a failsafe", eh, OK. It's an opinion. The other member flatly stated that they didn't exist, though, and that's what I addressed. You've jumped in and responded to a few things I've said to other members or just generally as though they were directed toward you, and not always considering the context, like assuming I was talking about Serbu doing destructive testing when the statements were about the utility of destructive testing in general, no mention of Mark, Scott, the RN50 or SLAP rounds in that post. I tend to be precise with my vernacular, really don't make vague or cryptic statements, allusions, comments that I intend people to extrapolate from, especially in discussions of a technical nature. Sometimes that comes with accusations of loquaciousness, particularly from those who only wait for an indication that it's their turn to talk, rather than listening to understand what's being said. As well, if I mean for a statement to be directed at and seen by someone specific, I'll use the features this board has to quote or tag that person.
denton
Member
Thank you! I had wondered for a long time why a case head separation causes such sharp recoil.
I haven't read the whole thread, but as you probably know by now, the Serbu did suffer a case head separation.
Double Naught Spy
Sus Venator
Which is really interesting. So the threads fail. Do we assume the cap was then projected rearward exactly straight?
I am sure Serbu assume they would work in tandem, mutually supportive, in the case of a failure, to stop the rearward progression of the cap. Combined, maybe they would have held, but maybe not individually. However, with asymmetrical force (cap coming off slightly angled), you can have sequential failure whereby one ear takes more force than the other ear and is overloaded and fails and then the 2nd ear is left trying to stop all the force and is then overloaded and fails.
The cap appears to have come straight back and snapped off both of the ears. Marks last video on this covered this and showed where the cap made multiple contacts before hitting Scott.
The force from this incident is amazing when you consider everything that happened and was destroyed. Scott is definitely lucky to be alive, it could've ended tragically.
The force from this incident is amazing when you consider everything that happened and was destroyed. Scott is definitely lucky to be alive, it could've ended tragically.
- Status
