Light charge detonation

[FA9]

This video is about poor quality ammo, what I fail to understand is how a light charge could be a factor in a kaboom. Is that even possible? fwd to the 2min mark or you could just watch from the beginning .
Reason for asking is because I reload 38spl, 3.2gr titegroup under 125gr. bullet and may go 3gn. instead.

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[Certaindeaf]

I think that that theory has been generally dismissed.. for a long time. I could be wrong though.
He fails to mention a "4th" potential culprit.. severe bullet setback.
Well, and a 5th could be a screwed up chamber to begin will.

 

[oli700]

This video is about poor quality ammo, what I fail to understand is how a light charge could be a factor in a kaboom. Is that even possible?

it is.
however it isn't the squib round, its the follow up shot the hits the stuck projectile that didn't have enough energy to clear the bore resulting in an epic pressure spike and breach

 

[elsie]

Depends on the type of powder. Remember that gunpowder is a propellant that burns rather than explodes. If a powder requires a lot of volume in the case then the powder burns from the primer until enough pressure builds up to start moving the bullet. Now if you undercharge it enough, then it becomes basically a fuel-air explosive because enough powder can start burning simultaneously that it spikes the pressure.

That is very rare though and normally you end up with a squib load.


elsie

 

[SinisterSouthpaw]

I have never seen any anyone ever give good or even plausible explanation of light load "detonation" this guy is as full of ____as all the others I have seen. Target shooters regularly load powder that fills the case even less than his example and have no trouble. One good thing about the internet is that on occasion we get to hear what really happened when the rest of the ammo is examined. All these "detonations" turn out to be either double charges or following rounds after a squib.

The "fuel/air" silliness is also bogus as the amount of air in a case full off powder is nearly the same as a case 1/4 full-lots of space between granules and the type of combustion mentioned requires not only a lot of O2 but there has to be an injection of O2 to get the process going. That's not going to happen in even the biggest cartridge case. Why look for silly reasons when the real causes are so simple? Unless the guy was shooting in the Bermuda triangle--was his name Berlitz?

 

[Benchrest]

I've read over and over that this potential exists, and over and over that NO ONE has been able to produce it intentionally.

My opinion is that it's bad theory, and that every condition that appears to match it is actually something entirely else.

.02

 

[Mikej]

3.0-3.2 of titegroup sounds pretty light to me. Assuming a revolver, and jacketed bullet. I find nothing that low unless you're using cast. You don't say barrel length, cylinder to barrel clearance....Unless you are trying to see how low you can go? Doesn't make sense to me why you don't want to run what's recommended as safe loads that won't blow the gun up/will get the bullet out of the barrel for sure.

 

[jluck]

Light loaded rifle cartridges is Is a very real and dangerous practice due to secondary ignition from too much air space in the cartridge/chamber. Pistol stuff I have no idea, I don't want to derail thread but also don't want to see light loading safety painted with with such a a broad brush. I know of one kid who took rifle parts to the face after grandpa made up some light loads for him, it tore old grandpa up terribly emotionally.

 

[Certaindeaf]

Yea, it's different with a rifle. One can use so little of or so little of a "slow" powder that the primer can punt it up the pike a bit and wham, the powder catches.. obstructed bore.
I've never had problems using "The Load" of around 10-13gr Red Dot in 30-06 and heavyish GC cast slugs. Red Dot is also position insensitive so there's no need for filler.
anyway

 

[FA9]

3.0-3.2 of titegroup sounds pretty light to me. Assuming a revolver, and jacketed bullet. I find nothing that low unless you're using cast. You don't say barrel length, cylinder to barrel clearance....Unless you are trying to see how low you can go? Doesn't make sense to me why you don't want to run what's recommended as safe loads that won't blow the gun up/will get the bullet out of the barrel for sure.

I myself like heavy stuff. This 38spl stuff is for my wife and her S&W 642. At first I was loading them @ 3.5gr TG under 125gr plated bullet, but she complained that it was too much for her so now, it's at 3.2gr. I'm thinking of doing 3gr. But I'm not sure...

 

[Darkker]

Yes light loads can go boom, not just in rifles.
Normal burning is called deflagration, detonation is bad juju.
Interesting thread on this over on shooters forum. UncleNick did a brilliant job of explaining the technical details of it.
https://www.shootersforum.com/ballistics-internal-external/102031-detonation.html

 

[Benchrest]

Theory.

 

[Benchrest]

Much like mine.

 

[Darkker]

Much like mine.

Except he showed how it is possible, and if you read through the thread there was a specific reference to a Speer employee who had repeated it several times with a Ruger Redhawk/blackhawk?

While that could also be some old wives tail, now that they got away from ATK, actual humans answer the phone again. I spoke to them a few weeks ago and discussed the cartridges in the new loading manual they are currently pressure testing for. If someone wants some verification, would be worth the dime to see if it can be.

 

[SinisterSouthpaw]

Now let's see him actually produce one

 

[P7M13]

Velzey posted a link to the Gun Digest article on PO Ackley <-- link here.
If I read it correctly, he tried for years and never achieved generating that theoretical pressure spike you can get with loading slow powders below recommended limits.
You definitely hear about it when reading on loading old powders like Thunderbird or Winchester MRP. Scared the crap out of me when I started using surplus powders.
Yet, having worked many times in explosive atmospheres, I can see it happening with fast powders like pistol. Who would think a case packed with flour or sawdust would propel the bullet, but if you're there when that unhappy convergence happens, well, you can kiss your arse goodbye....
Will have to read it -- thanks for the link Darkker!

 

[Darkker]

P7,
They aren't talking about Pressure spikes or secondary ignitions; but detonations.
Secondary ignitions or unexplainable pressure excursions are simple to reproduce with slow powders.
Charlie Sisk @ Sisk rifles can blow the final 10" of a rifle on command. The 7 RM and 243 have a nasty reputation at the ballistics labs for that as well. If you have your copy of A-Squared's manual they discuss it there also.

Secondary ignitions can happen alarmingly frequently, just at relatively moderate pressures. But how many of us in here care enough to buy Pressure testing equipment? Here's mine.

 

[tac]

I used to shoot around 500 rounds of .38Special per week, except for competition weekends, when I'd shoot around 660 in the two days. All of them were what would be classed as pretty squib loads, as they only had to shoot accurately, not blow holes in walls.

Not only did I never have a misfire, I never saw anybody else have one either, and I know all my shots left the barrel because I could SEE the darn things going down range. Still, the myth of so-called [over here, that is] surface detonation of small loads lying in the bottom of the cartridge case persist. And BTW, nitro-cellulose propellants BURN, black powder, being a Class 1 explosive, explodes, albeit comparatively slowly, hence its designation as a low-explosive. Such material develops an explosive shock front at about the speed of sound - say 680 mph or 1Km per second.

High explosive, on the other tentacle, goes off at between six and nine Km per second.

Examples - TNT has a detonation (burn) rate of approximately 5.8 km/s (19,000 feet per second), Detonating cord of 6.7 km/s (22,000 feet per second), and C-4 is even faster.

tac. who has been at the wrong end of both

 

[Certaindeaf]

About a quadrillion .38 148grHBWC's have been lofted downrange with 2.5-3gr Bullseye and a few guns were smithereened. Do the math.

 

[Capn Jack]

I believe the theory in action here was, The primer would flash across a sub load of smokeless powder laying in a cartridge case. The primer detonation would unseat the bullet pushing it forward to where it would lodge in the rifling, stopping momentarily, causing a dangerous spike in chamber pressure as the powder finally fully ignites.

I have personally had this happen, but though the bullet was stuck in the rifling, the powder did not continue too burn and I ended up with a "Squib."