YouTuber Kentucky Ballistics almost dies from 50 cal explosion

[MosinT53Hunter]

This post is not to take issue necessarily with anything else in your post, but I think this idea that the "almost universal" design is that the bolt is male and the receiver is female is not quite right. And a bunch of folks have mentioned it. However...

In Mausers, Remington bolt guns, etc. The chamber holds the cartridge. The bolt is behind the cartridge. What holds the bolt there? The receiver. What holds the receiver there? Male threads on the back of the chamber (barrel) interface with the female threads on the receiver. When a Mauser or Remington bolt gun fails, where does it fail?

Also, the ears on the receiver on Serbu's design seem to be stronger (yes, even in comparison to their respective cartridges) than the "safety lug" on Mauser 98s, and nobody complains about the safety lugs on Mauser 98s being too weak.

Or the safety lugs on an Enfield rifle, which are considered to be much weaker then a Mauser, yet they made millions of them, and still going in other countries.

I believe it wasn't the fault of the rifle as it was its operator. He knew the rounds were old, that they were not made for a rifle he was using.
Yet, despite all caution and reason, he kept putting round after round through it. He is at fault, and he suffered the consequences of his careless actions.

 

[Kano383]

In Mausers, Remington bolt guns, etc. The chamber holds the cartridge. The bolt is behind the cartridge. What holds the bolt there? The receiver. What holds the receiver there? Male threads on the back of the chamber (barrel) interface with the female threads on the receiver. When a Mauser or Remington bolt gun fails, where does it fail?

Also, the ears on the receiver on Serbu's design seem to be stronger (yes, even in comparison to their respective cartridges) than the "safety lug" on Mauser 98s, and nobody complains about the safety lugs on Mauser 98s being too weak.

Yes, on a Mauser system, the barrel is threaded into the receiver... And if the threads fail, it's the barrel that leaves the scene, not the receiver that comes back and hits you.

My point is about pressure exerted on the bolt face by escaping gases, and respective areas between a "classic" bolt face, and a female breach cap. This is the problem.

Next, the Mauser third lug... Mausers were produced in the range of 100 to 150 million units, and I have never heard of or seen a Mauser bolt flying back into someone's face. I don't mean it never happened, but I have never come across a documented case, and I've been searching for years - if someone has something in this regard, I'll be glad to have the story and the pictures. I have seen Mauser actions blown, some by firing the wrong ammo (oversize bullets), some by case overload: they were wedged solid, the magwells and stocks were blown, but the actions held and the shooters had only hand/forearm injuries, not even spectacular.

 

[Carl N. Brown]

https://serbu.com/content/RNExplodedView.pdf

The ears or fingers (design purpose = prevent closing the action to fire if the end cap not completed screwed shut) do not impress me as being as robust as a Mauser 98 safety lug. When the cap blew off Kentucky Ballistics' gun, the ears sheared off as shown in the video.


other notes

The warning on firing SLAP round through a barrel with a recoil brake is that the sabot will open as it releases the bullet and will strike the inside of the brake and fragments of the sabot will be blown out the vents in the recoil brake. Gas vented from a recoil brake is annoying enuf for bystanders, but plastic debris vented with the gas does not sound like contributing to a fun day at the range. The sabot hitting the recoil brake might explain the odd impacts of the bullets down range but it does NOT appear to be the cause of the kaboom. So I drop that theory.

Muzzle flash in video is hard to catch. The frame speed of the video could catch one flash and miss the other or get an incomplete image of a third, so the appearance of the flashes shot to shot in the video shows me nothing about the individual rounds.

Since the M2 Browning HB fires from a closed bolt and the M2 is approved for use with SLAP, my theory the sabot may have melted and adhered to the chamber due to heat is probably shot down.

 

[Dudedog]

Since the M2 Browning HB fires from a closed bolt and the M2 is approved for use with SLAP, my theory the sabot may have melted and adhered to the chamber due to heat is probably shot down.

Yes, I would think the barrel of an M2 firing full auto would get quite hot, and if the sabots are don't melt there, unlikely to melt in a single shot rifle.

 

[Elkins45]

I’ve never seen a documented case of all three lugs failing on a Mauser and the bolt exiting the receiver from the rear.

 

[Mauser lover]

I have not seen a Mauser with three failed lugs. However, neither have I seen the barrel threads shear off. That was my point. When Mausers and Remingtons fail, it isn't the female thread on the receiver/male threads on the barrel that fail (as far as I have seen). I think that the idea of the Serbu threads being weak is vastly overblown.

 

[Slamfire]

Next, the Mauser third lug... Mausers were produced in the range of 100 to 150 million units, and I have never heard of or seen a Mauser bolt flying back into someone's face. I don't mean it never happened, but I have never come across a documented case, and I've been searching for years - if someone has something in this regard, I'll be glad to have the story and the pictures. I have seen Mauser actions blown, some by firing the wrong ammo (oversize bullets), some by case overload: they were wedged solid, the magwells and stocks were blown, but the actions held and the shooters had only hand/forearm injuries, not even spectacular.

I have seen a number of pictures of commercial Mauser blowups, can't say the bolt blew out, but all the chunks that blew into the air can hurt. I can't find it now, but a shooter had a M1917 action blowup. I think it was one of those Kimber conversions to 300 Win Mag. The receiver was brittle and blew. The poster had all sorts of facial and jaw damage. And it was serious, like jaws wired till the bone regenerated, jaw damagte. The bolt on a M1917 is held in by the bolt handle, so he must have been hit by wood and metal fragments.

You can imagine there were a lots of metal fragments in the air when this receiver blew



Ditto



I did read a post of someone killed by one of those low number M1903's. The poster talked to a woman whose Dad was killed when his DCM M1903 blew up while shooting.

I don't think Paul Mauser, or any gun designer, designed his weapon to fragment safely. I don't know how you can do that. Designers try to design the weapon, that if it stays in one piece, that gases and metal particles are vented away from the shooter. But once the receiver blows, there is no more structure to protect the shooter.

I don't have the 50 caliber rifle, nor examined one, but I am of the opinion that a screw thread breech can be very strong. Look at the barrel extension or an AR10/AR15. I have not heard of the extension threads shearing.



The earlier analysis that 36,000 psia could rip the cap off, well, sure. Was the case head cracked and let gas out, like this:

 

[Kano383]

I have seen a number of pictures of commercial Mauser blowups, can't say the bolt blew out, but all the chunks that blew into the air can hurt. I can't find it now, but a shooter had a M1917 action blowup. I think it was one of those Kimber conversions to 300 Win Mag. The receiver was brittle and blew. The poster had all sorts of facial and jaw damage. And it was serious, like jaws wired till the bone regenerated, jaw damagte. The bolt on a M1917 is held in by the bolt handle, so he must have been hit by wood and metal fragments.

You can imagine there were a lots of metal fragments in the air when this receiver blew.

I did read a post of someone killed by one of those low number M1903's. The poster talked to a woman whose Dad was killed when his DCM M1903 blew up while shooting.

I don't think Paul Mauser, or any gun designer, designed his weapon to fragment safely. I don't know how you can do that. Designers try to design the weapon, that if it stays in one piece, that gases and metal particles are vented away from the shooter. But once the receiver blows, there is no more structure to protect the shooter.

I don't have the 50 caliber rifle, nor examined one, but I am of the opinion that a screw thread breech can be very strong. Look at the barrel extension or an AR10/AR15. I have not heard of the extension threads shearing.

Yes, I'm aware of these types of accidents, but they're due to defective heat treatment: manufacturing defect, not design defect.

As you say, the Mauser action is designed in such a way that gases and particles have ways to escape without endangering the shooter, and are vented so efficiently that the action doesn't blow up (provided it has been manufactured the way it was supposed to...).

Threads are very strong, but if the force exerted exceeds their shear strength, they fail... And in the RN-50 design, that force can easily be exceeded if a case ruptures like the one in your picture, especially since there is absolutely no way provided for the gases to escape, relieving the pressure. That's a "Oops... Didn't think of that" that should not happen in gun design.

 

[Robert]

We are going in circles on this one, let's call it a day.