Dr T
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If the ammo seller was the counterfeiter, he would disappear.
More on Kentucky Ballistics - Serbu
- Thread starter Jim Watson
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D.B. Cooper
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Looks like the manufacturer released a couple videos on why the gun blew up. His claim is someone put pistol powder in the case. I haven't watched the videos in their entirety, but thought I'd share them here for those who might be interested.
General Geoff
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Seems plausible to me
Carl N. Brown
Member
My theory is that those SLAP rounds were "replicas" slapped together from components (or fake components) meant to be held as examples or as collector items only, and not to be fired. Probably passed through multiple hands before reaching Kentucky Ballistics and may have been repackaged.
someguy2800
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Not buying it
D.B. Cooper
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Me neither.
General Geoff
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Why would they have any live powder in them if they were made for display purposes?
Jim Watson
Member
As we saw, ol' K.B. shot up the remaining suspect ammo and sure enough, wrecked another Serbu.
All we have left is speculation and mathematics.
As I mentioned above, a guy here managed to NOT blow up an Armalite AR50 with Varget instead of H50BMG, so how far back up the "burn rate" scale do you have to go to grenade a gun?
All we have left is speculation and mathematics.
As I mentioned above, a guy here managed to NOT blow up an Armalite AR50 with Varget instead of H50BMG, so how far back up the "burn rate" scale do you have to go to grenade a gun?
D.B. Cooper
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That's why I'm not buying the story that it was the ammo. What we need now is a "melt down" test with another Serbu zip gun home made 50 cal, using factory spec ammo, and see if that blows up, too.
The Glockodile
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Such an event would give me enough PTSD to never touch a firearm again...
someguy2800
Member
Well for me I don’t doubt that the ammo was indeed very high pressure and defective. The issue to me is that the design of this rifle is such there is no gas venting at all and it allows gas from a ruptured case to act on a much larger surface than the case. The same ammo in another gun would still probably rupture primers or cases, but that gas would have a way to exit the firearm without blowing a steel hockey puck into your face.
mgmorden
Member
Varget is naturally way too fast for .50 BMG, but its WAY slower burning than any pistol powder. Hodgdon lists loads for that powder in cartridges as far up as .375 RUM.
Also it can be a question of HOW MUCH powder is used. 10gr of Alliant Unique is commonly used in rifle cartridges as a light plinking load. Throw 50-60gr of that same powder in there which is often the amounts used of the proper powder, and the pressures are a whole different story.
If you look at the load data though via QuickLoad (screenshot 1 below), you'll see that if you substituted Varget at the rate of 288gr (the amount of H50BMG that you'd use), you're looking at a peak chamber pressure of 166,212 PSI. That's much higher than .50BMG is supposed to be at but still within the "safety factors" of many actions. I think I remember Serbu mentioning a 165k figure for what his action would withstand. That's right in the ballpark.
Now if you instead look at that much Alliant Bullseye though, you're looking at a peak chamber pressure of 481,921 PSI (screenshot 2 below). That's nearly triple the pressure from Varget. No need to go through every powder known to man but I checked a lot of various pistol powders and all were in the 400K+ PSI range. Almost no action will stand up to that kind of pressure.
Also note the pressure curve between Varget and the pistol powder - the pistol powder pressure has shot through the roof within 0.025s whereas the Varget load being a slower rifle powder (too fast for this action, but still slower) is still a somewhat gradual pressure curve building up to max pressure over 0.25s.
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I'm far less interested in what caused the failure and far more interested in how the design of the gun handled it. It's not unheard of for defective ammo to find its way into firearms and that means that it's critical for firearm designers to insure that when such things happen, the failure mode of the gun protects the user.
125 years ago, Mauser was designing his rifles so that if there was a case failure the gas would be vented away from the shooter and so that the receiver had a safety feature preventing the bolt from blowing back into the shooter's face even if the bolt lugs failed in a catastrophic incident.
125 years ago, Mauser was designing his rifles so that if there was a case failure the gas would be vented away from the shooter and so that the receiver had a safety feature preventing the bolt from blowing back into the shooter's face even if the bolt lugs failed in a catastrophic incident.
Exactly this. Too many people are focusing on the ammo, "hot load", "pistol powder", "sabot strike". Or just "user error". All of that doesn't really matter because even regular factory ammo can cause an overpressure event or massive gas leak. A gun should be built to protect the user from such things. Do I want a gun that shoots the firing pin into my brain if there's a case rupture? "User error" doesn't excuse bad design...
DeepSouth
Random Guy
I don’t think it’s reasonable to expect a gun to fail in safe manner. I met a guy once that found his dad dead in a duck blind because one of the barrels on a double barrel shotgun split starting at the breach sending the blast into his face.
I can’t think of a reason that isn’t possible on nearly all break action guns. It’s just that anytime you’re dealing with that much pressure and power the potential for it go wrong in a life ending manner is there, I don’t think that is avoidable.
failures can be mitigated but not completely ruled out, and they are very unpredictable and therefore impossible to control.
I can’t think of a reason that isn’t possible on nearly all break action guns. It’s just that anytime you’re dealing with that much pressure and power the potential for it go wrong in a life ending manner is there, I don’t think that is avoidable.
failures can be mitigated but not completely ruled out, and they are very unpredictable and therefore impossible to control.
mgmorden
Member
I agree, and even if it were its all a question of levels. Guns have safety features to deal with failures but they can only go so far. Think of it like a car: you have airbags, seatbelts, etc to protect you in the case of a crash. At 35 MPH they work pretty good. At 60-70 MPH they usually work pretty good too. If you crash at 150MPH they're not going to do a lot.
Similarly, most of the safety features on guns are going to still deal within a range of failure levels. A cartridge that is slightly overpressure, a pierced primer, a bore obstruction, etc. Most guns that handle a 2-3x overpressure cartridge just fine without harming the shooter would likely still kaboom into a pile of shrapnel if subjected to a 7-8x overpressure cartridge.
That's why the "why" the gun failed is important here. If it's a minor event that could happen from any box of factory ammo that's a major concern. If its an extreme scenario that's less important.
The reality is that the gun wasn't some one-off basement gun. Serbu has made hundreds (maybe even thousands) of them. They're not out there exploding left and right. Kentucky Ballistics is the only reported failure and he was using highly suspect ammo.
someguy2800
Member
ever notice that pretty much every bolt action rifle in existence has a hole drilled through the side or top just forward of the locking lugs? I wonder what that is for?
someguy2800
Member
Something akin to this is what I think happened. An overpressure round blew the case head and let gas into the breach. Earlier in this thread I calculated that it would only take about 46K psi acting on the inside of the breech cap to shear the threads off based on Serbu’s numbers. Milling a couple 3/16”x 1/2” vent slots at 10 and 2 o clock in the breech cap would ensure this pressure build up cannot happen and would vent the gas up and away from the shooter.
David Hoback
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You guys talking about “safety features” in the event of a KB, don’t seem to understand the physics of pressure. A 308 can fire at 60,000psi. A bullet set back can I that up to over 100,000psi. And it will likely blow up the gun. Now take a 50BMG at the same thing, but this time it’s in an UPSIZED Action. If it were the 308 in the Serbu Action, that 100,000psi would not have touched the Serbu. But now take the 50BMG, which can develop pressures MUCH higher than 100,000psi. And it’s 100,000+psi from a .804” diam. surface area vs .473” diam surface. area. Which can produce almost DOUBLE the impact force! You want an Action that will prevent a safety issue to the shooter? Sure, it’s called the Ma Deuce! Oh, but that’s MUCH too large an Action, right?
You guys ASKED for it. You who bought them! An affordable 50cal, shoulder fired rifle that doesn’t weight 50lbs! They can only use so much steel. The Action can be only so large. Had the lugs been 3/8”, 7/16” or maybe even 1/2”, surely it would have held. Had the cap been 2, maybe 3 times. as long with the the equivalent extra length in threading…sure it may have held. Who knows. Point is, you play with cartridges THIS powerful, and want manageable sized firearms to shoulder fire & be able to easily carry, than you take on the gamble of of being seriously injured or killed, when a bad round goes through the weapon.
For anyone who still doesn’t get it… guns are dangerous!
You guys ASKED for it. You who bought them! An affordable 50cal, shoulder fired rifle that doesn’t weight 50lbs! They can only use so much steel. The Action can be only so large. Had the lugs been 3/8”, 7/16” or maybe even 1/2”, surely it would have held. Had the cap been 2, maybe 3 times. as long with the the equivalent extra length in threading…sure it may have held. Who knows. Point is, you play with cartridges THIS powerful, and want manageable sized firearms to shoulder fire & be able to easily carry, than you take on the gamble of of being seriously injured or killed, when a bad round goes through the weapon.
For anyone who still doesn’t get it… guns are dangerous!
JoeTester
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EXACTLY.
NOTE 9/17/22 15:11 CST: The following is my opinion and are not claims I intend as factual - only my opinion.
They did not design the gun with any thought towards:
"when this gun inevitably blows up from an over-pressured chamber - how can we make sure it fails in a manner/direction least dangerous to the shooter?"
Instead of doing this, and instead of doing ANY destructive-testing, Serbu thinks he shouldn't have to worry about it, because it's the "bad ammo" that caused the failure - and because he has a lawyer (I'm not joking, watch his last video unless he deleted it, he says he's fine because he has lawyers. Not joking at all).
NO ONE doubts the ammo caused the failure Mr. Serbu. That we understand.
What is inexcusable is:
LETTING YOUR CUSTOMERS BE THE ONLY ONES ONES TO DO DESTRUCTIVE TESTING OF YOUR FIREARM!
So what happens the next time a customer inevitably gets an over-prsssured round or bore-obstruction? Mark Serbu, in his latest video, says he not worried about it because he has lawyer, and they say legally he's in the clear and not at fault...
...ANOTHER OVER-PRESSURED ROUND OR BARREL-OBSTRUCTION WILL OCCUR - IT IS INEVITABLE.
So even if he is legally covered the next time it happens (I question his legal confidence here) . MORALLY, by not making ANY changes to a design ( a design that is LETHAL when it fails) to protect rhe next person shooting the gun when it fails, and therefor therefor putting the shppter in the direction of ALL the gun's failure-point's shrapnel, is simply EVIL.
I am shocked by the calloud attitude he is taking towards the next one of his loyal customera this happens to.
In his latest, he mocks ForgottenWeapons.com's Ian Mccollum as "gun jesus", and says essentially he shouldnt he listened to.
If you watch the Forgottenweapons.com video, "Why Guns Explode", Mccollum goes over the near-countless things, that other manufacturers do, to prevent situations like this happening (or in the worst case, to fix them after they happen)!
Unlike Serbu, they all seek to design intentional failure points, and destructively test them to ensure the failures happen in as a safe manner as a failure can happen.
Mccollum also discusses what other manufacturers have done when their guns designs have inured people when they fail... unlike Serbu, their policy isn't to do nothing and talk to lawyer when it happens.
You know Serbu's not protecting his customers with an improved design?
Because doing so would be tacit admission of fault, and put him at risk legally for lawsuits. Not to mention, a redesign to improve safety would necessitate a very expensive recall.
SO INSTEAD OF PROTECTING HIS CURRENT AND FUTURE CUSTOMERS FROM DEATH & MAUMING, WHEN DOING SOMETHING AS SIMPLE AS ADDING MORE THREADING WOULD HELP, HE WON'T BECAUSE IT COULD COST HIM MONEY.
...but no, just ignore little "gun jesus" and MAKE NO IMPROVEMENTS to your guns failure-points.
Cars have crumple zones, and guns have designed failure points as well. Both are products that can KILL you when things INEVITABLY go wrong. SO manufacturers know they MUST design (or redesign) the products in a way, so that when they DO fail, they fail im a DESIGNED way to decrease the chance that the product will KILL you... WELL, UNLESS YOUR MARK SERBU.
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But not everyone wants an extra 5lbs on a rifle so they can be stupid with it.
How many stupid people have blown up or trashed Rugers because "Rugers can handle it".
Make it strong enough to withstand gunshow mystery reloads that at the very best case scenario are specifically warned not to be used, and someone will still blow it up.
That said, this rifle is stupidly designed. An interrupted thread plug with a few hours of amateur engineering would make this 3x as strong, 100 times as durable, and 10x easier to use.
@JoeTester and others, did you watch the video? Guessing not, go back and watch the last two videos posted.
If you're saying that Mark didn't test this gun before offering it for sale, I know you didn't.
Have you fired one? I have, a friend that has his 06 FFL, makes custom ammo, owns one. He's fired hundreds of rounds through his. Not once, with safely made ammo has it ever had an issue.
I've seen guns blow up in people's faces, to the point that the gun was destroyed and they were injured. The fact that KB posted the video, now makes everyone an expert on what happened.
The last 50 BMG that I heard Kaboom was traced back to the shooter. New to reloading, beat the bolt handle down on ammo that wasn't loaded properly...
I was lucky that I wasn't at the range that day as it happened at the range I go to. I think the story went that when the gun blew, the bolt went through the top of his shoulder. Shrapnel tore up his hands and face.
Moral to the story, guns can be dangerous when you don't respect them and the power they produce.
If you're saying that Mark didn't test this gun before offering it for sale, I know you didn't.
Have you fired one? I have, a friend that has his 06 FFL, makes custom ammo, owns one. He's fired hundreds of rounds through his. Not once, with safely made ammo has it ever had an issue.
I've seen guns blow up in people's faces, to the point that the gun was destroyed and they were injured. The fact that KB posted the video, now makes everyone an expert on what happened.
The last 50 BMG that I heard Kaboom was traced back to the shooter. New to reloading, beat the bolt handle down on ammo that wasn't loaded properly...
I was lucky that I wasn't at the range that day as it happened at the range I go to. I think the story went that when the gun blew, the bolt went through the top of his shoulder. Shrapnel tore up his hands and face.
Moral to the story, guns can be dangerous when you don't respect them and the power they produce.
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