50 cal explodes on video

[Capt. Oblivious]

That's hectic, I have watched quite a bit of his videos on youtube and his a very cool guy. Hope he makes a full recovery

 

[457ciSBC]

Trauma training and keeping his wits about him saved his butt, anybody untrained and panic stricken would have possibly bled out. So, the CIP 50 BMG max pressure is around 54,000 PSI and that was estimated at 85K, that sheared off lug almost killed him.

 

[jelenko]

This video is terrifying and reminds me of why I only shoot what I reload, and also why I buy rifles of known origin and safe design.

++

 

[davidjoe]

Trauma training and keeping his wits about him saved his butt, anybody untrained and panic stricken would have possibly bled out. So, the CIP 50 BMG max pressure is around 54,000 PSI and that was estimated at 85K, that sheared off lug almost killed him.

I heard that and it was troubling that 85 was thought to be the explanation.

Well, let’s say it was 85k psi even though it was a plastic shrouded sub caliber lighter projectile. That’s what, some 1.5 max, or approximately what a proof mark indicates, that so many barreled actions are tested at without being considered to have incurred any damage in merely conducting the rest?

So, would 75k have blown the cap off but not sheared both lugs? 65k made the cap inoperable? I’m more inclined to think that after high count use those threads either fatigue or the two diameters diverge.

There are articles describing much smaller actions handling many multiples of 54k without sending steel rearward.

 

[DRNewcomb]

That design aims the overpressure failure point at your face, no thanks! AR's and bolt actions seem to fail so that the bolt stays in the gun and not in your face.

So much effort has gone into the design of modern rifles to account for what happens if: 1) the case or primer fail or 2) the primary locking lugs fail, that is seems to be that the design of the rifle in question should probably be considered "experimental". The other question I would have is about shooting sabotted rounds from a rifle with a muzzle brake. I thought there was an incompatibility between sabots and muzzle brakes due to there being an undefined event when the sabot interacts with the brake. This is why tank guns no longer sport muzzle brakes.

 

[jdh47]

The video did not address any damage to the muzzle brake but I suppose it could've occurred. The thread tenon and cap do not look to me to be long enough but pictures can be deceiving. I am guessing that since it was old ammo, the powder could've been degraded. It can happen a number of ways, heat and handling. The catastrophic way it failed makes me think it was north of 85K PSI. Just my WAG.
God Bless him. I hope he makes a full recovery. He can thank God, his father, the doctors and his great health, calm nerves and fitness for his good outcome. They did all the right things and it worked out well.

 

[Bill Norris]

A threaded breech is very strong, but I think the brilliance of modern bolt guns is not in how they seal up and contain the pressure, but in how they relieve it when the case ruptures.

There is no telling if it would have made a difference, but most bolt guns direct pressure out vents in the side of the receiver, away from your face, when a case ruptures. I don't think this rifle has any provisions to do that; it's a sealed up chamber.

This video is terrifying and reminds me of why I only shoot what I reload, and also why I buy rifles of known origin and safe design.

+ 1

 

[rockrat]

GotRDid---That 50 cal saboted round of yours, next to the 30 cal., kind of looks like one someone had loaded it. I believe SLAP rounds use a hardened (Tungsten?) projectile instead of the AP black tip bullet that is loaded in your round. Many years ago you could buy sabots for a 50 cal and put whatever 30 cal. bullet you wanted in the sabot.
The 1945 round you have looks interesting!!!

Sure glad the guy survived pretty well intact.

 

[Catfur]

Ian McCollum (aka Gun Jesus) of Forgotten Weapons just put up a very nice video in response to this video, talking about all the way guns go boom (in the improper way), and some about how designs mitigate this.

 

[Bill Norris]

I might flinch after that, or only shoot a bow.

I imagine going forward that would probably put a little "hitch" in my git-a-long every time I was at the bench.

 

[DRNewcomb]

Ian McCollum (aka Gun Jesus) of Forgotten Weapons just put up a very nice video in response to this video, talking about all the way guns go boom (in the improper way), and some about how designs mitigate this.

 

[scope eye]

That load had to be well over 100,000 psi to create that much carnage, and I mean "well over"

Dean

 

[joshb]

So this gun is really a 50 caliber zip-gun? Hmm.......NO THANKS!!

 

[ebb]

Mark Serbu has been making 50 cal rifles for 17 years, this model is not the one that he started with but Ive never heard of one coming apart before. I think I am going to wait and see what the investigation says before I blame some ones rifle. It may well be that the breach cap will handle more pressure than the bolt in other 50s. One poster said surplus ammo gets shot everyday. What do you think some third world country does with ammo that the army won't shoot anymore cause it is blowing up rifles. They send it to America.

 

[M-61]

What do you think some third world country does with ammo that the army won't shoot anymore cause it is blowing up rifles.

"Operation Eldest Son"

 

[riflewoman]

I shoot 50’s, have three of them. Freeze the video at 5:03. Just take it in for about 5 full minutes.

That threaded stub is maybe about 1/2 as long as it is wide, and the first two full threads didn’t even strip, as I see it. What does that mean. To my thinking, that’s really a problem, to engage such limited threading.

Kentucky believes the Slap muzzle fire ball was large indicating hot loads but it could also be that they simply exit the barrel before the powder is burned like light bullet 22-250’s, because they are light, and that one of the Slaps recorded with a smaller flash was the exception. I wonder what the brass looks like.

If this threaded barrel was offered to me as pictured with that stub being a proposed “tenon”, just to hold the barrel on a receiver, I wouldn’t feel very comfortable with its proportions for even that limited purpose, let alone containing pressure repeatedly.

This is just my opinion as a shooter and rifle user, but I’m going to want more steel in contacting engagement, and behind the contact surfaces, than I see, and not in angles to each other that rearward recoil thrust over time can work to lessen, either.

My personal opinion is if my action is going to fail, the brass better not still look good.

I think the interrupted threads used in cannon breeches, although also angled, are taller and deeper relative to their diameter.

The threaded breeches (Welin Breech) are also buttress threads, and their “lead angle” is substantially less.

 

[jackieschmidt]

The threaded breeches (Welin Breech) are also buttress threads, and their “lead angle” is substantially less.

Weldon breech blocks are not a buttress thread. I have seen quite a few, and they are close to a 60 degree thread.

 

[jackieschmidt]

Weldon breech blocks are not a buttress thread. I have seen quite a few, and they are close to a 60 degree thread.

 

[davidjoe]

... in any case, his guns’ uniquely designed feature is the cap, (that basically replaces a receiver and its bolt) and it per se, didn’t fail, rather the threads on the barrel did, and the lugs behind the cap certainly didn’t back up those threads.

I don’t think any maker or competitive type asks or expects this much of tenon threats. We typically tighten them a few times at most in the barrel’s life and engage more of them. On his design versus a conventional design, the remainder of the gun is not attached to the cap, like it is to the receiver.

Conventionally, the threads have to be strong enough to keep the barrel attached to the receiver as the receiver starts moving backwards,

The difference here is conceptually similar to putting a 50 in the a clamp of a machine rest that could either be attached to the receiver, or, to the barrel. If you clamped the barrel, I suspect that a LOT more energy is transferred to the threads than if you clamped the receiver.

 

[DRNewcomb]

I think there are some valid points here: