General GunTuber thread

[SmokeyMcRunFast]

Shear capacity and tensile capacity are not the same thing, and it’s not just semantics.

In this case the shear strength of the threads should be compared to the hoop stress of the barrel. I would want the barrel to rupture before the cap came rocketing back.

Spoiler: More engineering sperging

most calculations use tensile strength as the basis as it is one of the numbers that is easy to experimentally measure. Modifiers to that number are then used for different types of stress. The calculation for thread shear failure is based on force and calculated shear area. Force divided by area is pressure and would give you the failure pressure. In threaded fastener design (bolts) the thread shear strength (when the threads strip) is supposed to be twice the ultimate tensile strength (failure point) of the bolt itself.

Give me a couple of hours I will dig out my machine design reference books and make an educated guess as to how high the pressure was.

 

[Pocket Dragoon]

Is this a dig on Ian making a video? Or guntubers as a whole?

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The part about "less optimal designs" sounded more like a dab on Serbu, not a dig on Ian.

 

[UVB-76]

The part about "less optimal designs" sounded more like a dab on Serbu, not a dig on Ian.

But Ian sort of did a video on how all kabooms are barrel obstructions, Karl says barrel obstructions are only one of the failure modes.
Ian did a video on the subject, Karl says it's impossible to make an intelligent statement until more information is uncovered.

 

[Pocket Dragoon]

Agreed; he's a lazy hypocrite.

 

[Pocket Dragoon]

Taufledermaus fucking wrapped the receiver of his shotgun with kevlar, shooting 70's production S&W sabot slugs, while overlaying some numbers about safe chamber pressures. What a cuck, lol.

 

[JJLiautaud]

Taufledermaus fucking wrapped the receiver of his shotgun with kevlar, shooting 70's production S&W sabot slugs, while overlaying some numbers about safe chamber pressures. What a cuck, lol.

I wouldn't call him a cuck, just using this time to remind viewers that every time they fire a gun there's literally an explosion happening a few a inches from your face, which a lot of people forget, its like after a serious workplace accident everyone follows the rules to the letter for a few weeks and then they slow start to slack off.

 

[S.C.U.D.]

Cokeman's shooting guns inside his car again.

 

[UVB-76]

I wouldn't call him a cuck, just using this time to remind viewers that every time they fire a gun there's literally an explosion happening a few a inches from your face, which a lot of people forget, its like after a serious workplace accident everyone follows the rules to the letter for a few weeks and then they slow start to slack off.

The problem is that he straight up posted a video criticizing KB for uploading his catastrophic failure, where he brings up 5 reasons he shouldn't have done it. Those 5 reasons were actually two, concern trolling about the potential that his video becomes a meme/fail video and worrying about money. I actually think KB did a huge service by posting the video, and Taofladermaus says he shouldn't have done it because it hurts the bottom line.
Now he's wrapping some ebay expired kevlar panel over a shotgun. If he was seriously concerned with those old slugs kabooming his shotgun he'd fire it remotely, and then resume his normal shooting habits after a few videos of shooting modern production/his own reloads because people tend to slack off once the perceived risk is gone.
If it wasn't for his previous video I'd dismiss it, but now there's a massive contradiction - youtubers can't show how dangerous guns are because it feeds the gun fails videos and demonetization, but now he's showing off his kevlar blankie. There was a time he wouldn't even show the shotgun and call it a mass accelerator to try and keep his show monetized. And you can bet that if the shotgun did blow up with the kevlar he'd post the footage "for science". There's nothing wrong with what he's doing but he can't go on policing the community while acting like this.

 

[WhoBusTank69]

Two whole years to replace the barrel of a muzzleloader. This is why Bubba goes at his guns with a dremel tool.

 

[HelpingNoone]

WWSD

edit:
honestly not the end of the world. It's just nice to see people finally question the WWSD "perfection" meme.

 

[SmokeyMcRunFast]

WWSD

View attachment 2147576
edit:
honestly not the end of the world. It's just nice to see people finally question the WWSD "perfection" meme.

Thats a cooling issue with the molds. Warpage like that is usually from uneven cooling of the material.

Also with gaps like that it will never pass the sooper scientifik mud test.

 

[HumptiDouji]

Is this a dig on Ian making a video? Or guntubers as a whole?
View attachment 2144479
View attachment 2144485

He's right in that it's conjecture, and pretty stupid conjecture considering the failure happened on the breech end. He's also right in that you'd have to take a look at the ammunition and gun in question, but at the same I don't see why someone like Ian (who has an engineering degree), couldn't look at all this and make an educated guess.

I would very much like Karl from InRange TV to explain to me precisely what other scenario besides a barrel obstruction creates stresses that fucking high.

Maybe he's one of those many people who misinterpreted it when Ian said that an insane overcharge like that essentially creates a situation akin to a bore obstruction?

 

[Club Sandwich]

Ian (who has an engineering degree)

an AS in M.Eng and a CNC cert from a decade ago isn't much of an engineering background.

the failure point appears to be an unintended pressure dwell time where the low yield stressors were enough to overcome the clamping force of the threads of the end cap. a relief through-hole or interrupted thread design would have been much better and arguably stronger (as seen on Weatherby rifles, or conversions of Mauser actions that had increased peak pressures for modern ammunition like the .308 Winchester vs the older 8mm Mauser). to put it another way: the strangely "lengthy" dwell time at peak pressure for .50 BMG is from it's design as an essentially up-scaled .30-03, and is also why nearly all .50 BMG firearms are either interrupted threads (for the additional strength and yield response over more than 4 threads) or short recoil. going a different approach, like the PTRD, you see a derived Mauser-like action with relief through-hole allowing some flex instead of buckling or yielding.

without examining the ammunition, spent cartridge, and the remains of the product in question, it's a bit up in the air. the photos point to a combination of factors though. a bore obstruction would be pretty low on the list of possible causes unless the sabot of the previous shot somehow remained in the barrel very close to the throat - enough into the bore that a new cartridge could be fed. while it's true that sabotted ammunition tends to not play well with muzzle brakes or devices of any kind, that isn't the case here.

 

[Akran]

---

Here is a fascinating video i was recommended, i thought this footage was before the AWB but then read the description and realized the timestamps on the video. Some of the replies in the comments he's made are a mixture of depressing, insane, and occasionally funny.

 

[S.C.U.D.]

---

Here is a fascinating video i was recommended, i thought this footage was before the AWB but then read the description and realized the timestamps on the video. Some of the replies in the comments he's made are a mixture of depressing, insane, and occasionally funny.

The fact that all they did was apparently just take his guns away and not even prosecute him is mind boggling. I can't believe it.

 

[Club Sandwich]

The fact that all they did was apparently just take his guns away and not even prosecute him is mind boggling. I can't believe it.

BATFE never wants to go to court over purely gun charges because they're constantly on shaky legal ground regarding self-made guns that are not sold across statelines or where they have to "interpret" technical details of a gun to legal effect (AZ had a VFG on a pistol that the ATF claimed was an illegal NFA item - AOW and was on the verge of losing the case because the pistol the grip was on had no other mechanical changes and it was pointed out a grip was safer than using a bare hand to grip the frame. pistol in question was a TC Contender).

they will usually broker deals with individuals. where they do have some legal backing is the sale or transport over state lines via the stupidly broad interpretation of the commerce clause.

 

[White Devil]

BATFE never wants to go to court over purely gun charges because they're constantly on shaky legal ground regarding self-made guns that are not sold across statelines or where they have to "interpret" technical details of a gun to legal effect (AZ had a VFG on a pistol that the ATF claimed was an illegal NFA item - AOW and was on the verge of losing the case because the pistol the grip was on had no other mechanical changes and it was pointed out a grip was safer than using a bare hand to grip the frame. pistol in question was a TC Contender).

they will usually broker deals with individuals. where they do have some legal backing is the sale or transport over state lines via the stupidly broad interpretation of the commerce clause.

Didn't they recently have to drop out of something because if it was ruled against it would determine that AR receivers aren't "firearms"? I remember something like that coming up in the past year or two.

 

[WhoBusTank69]

Didn't they recently have to drop out of something because if it was ruled against it would determine that AR receivers aren't "firearms"? I remember something like that coming up in the past year or two.

A former fed goes around testifying on the technicality that the AR lower doesn't fulfill all the requirements to be a receiver, and it's done a lot of people good.

 

[Club Sandwich]

Didn't they recently have to drop out of something because if it was ruled against it would determine that AR receivers aren't "firearms"? I remember something like that coming up in the past year or two.

i think so... something about how at which point is a receiver a firearm, as they had busted someone for having unmarked, yet finished, receivers. they were spare parts for RMA'd weapons that would need the SN engraved from the original weapon i think... might be a different instance, but it's happened more than once where they will make a deal to avoid a ruling.

 

[wopirish]

Speaking of split casing with the pressure coming out the back of the rifle. The only time I ever had a split casing it felt similar to what people describe as a squib round and then the gas leaked out from inbetween the upper and lower receiver and the ejection port. Certainly made for an interesting range day.

Anyone ever get a squib round though?


There was a story awhile back where a guy would let people pay to use his CNC machine and he got glowed for it.

“Dr. Death” pleads guilty to making, selling AR-15 rifle components

You can't pay someone who's unlicensed to mill a lower into a firearm.

arstechnica.com

Spoiler: glowed hard

…took one of the blanks and assembled a jig around the blank. Crowninshield then directed the UC to place the blank into a CNC machine, owned by Crowninshield at C&G Tool and used to mill out machine parts. Crowninshield then directed the UC to close the safety door on the CNC machine and to hit a specific button to start the machine.

During this time, the UC observed another customer that appeared to be doing the same thing at another machine. The UC overheard Crowninshield and another employee discussing a customer purchasing blanks. These blanks were known colloquially as blanks because they purportedly constituted 80 percent of a completed firearm and could be milled out at machine shops into completed firearms. The UC inquired if Crowninshield sold such blanks. Crowninshield showed the UC an inventory of such blanks for sale. The UC purchased a blank for $260, a gray blank for $180, and an aluminum blank for $160, all from Crowninshield.