Light charge detonation

[Certaindeaf]

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."

And that's code for?

 

[Capn Jack]

And that's code for?

"Code" ???? Just my observation and an experience I had...
Your Mileage May Vary.

 

[Certaindeaf]

Settled then.
lol

 

[orygun]

I once loaded 38 Special charges in 357 Maximum cases. The years have erased the reason why I wanted a "target" load for that gun. I was fortunate enough to recognize the fact that the bullet hadn't left the barrel before I tried to send another one down range, messing up my gun. I was able to knock the swaged lead wadcutter out with a cleaning rod. After I repeated this error, I decided my idea wasn't a good one.
I returned home to dig a bit further into my old Lyman manual to learn why my idea was stupid. This is when I learned about the potential for detonation.
If it hadn't been a revolver with a cylinder gap, I may or may not have had more of an issue.
Since then I've read of PO Ackley's attempts to duplicate detonation, to no avail, but the theory still seems to be regarded as a possibility.
These days we have powders for reduced loads that fill the case and eliminate the potential, no matter how low, of detonation happening.
But since my issue happened before everything was captured on the internet for all to see, you'll just have to take my word for it.

 

[AMProducts]

So, for years I worked for a major manufacturer of "Cowboy Action" ammo, about the only requirements on this stuff was that it made power factor, which for most loads seemed to mean moving bullets at velocities I would expect from paintball guns rather than centerfire firearms.

I'm not really sure you could possibly get any more "worst case" than a 165gr bullet in a .45LC, loaded with the same amount of powder you would put in a .22LR. We never once had a customer call in to complain about his gun blowing up for any reason, much less for having "too little powder". And I personally loaded millions of these rounds. For reference, we did get a lot of calls for some 9mm loads done by a company that happened to share our name (we didn't even load 9mm) that the owner of the other company had dumped at a gun show.

The myth of "detonation" is pretty silly... Detonation involves a shock wave moving through the explosive, at which point it breaks down chemically, and releases it's energy usually at a few km/s. Despite the fact that modern smokeless powders are made of the same compounds you would normally find in the anarchist cookbook for dynamite recipes, the real magic of smokeless powder is the form it's in. Those sticks, balls, or flakes coated with graphite and mixed with a variety of other compounds un-do the potential for detonation in any meaningful way. The other problem with this theory, is that detonation starts with a detonation, a blasting cap starts a detonation by first detonating. Small arms primers deliver much lower energies. The only thing that comes close are shotgun primers, which are sometimes used for setting off shock-tubes, however even then, those use still another booster charge on the end to transfer the explosion into the bulk explosive.

As an addendum, not only have I loaded conventional metallic cartridges with small amounts of powder, but I have also loaded 40 and 37mm cartridges. In most cases, a charge of about 4 grains of powder is enough to throw that 8 oz grenade out the muzzle at about 300FPS, and 37mm is loaded with black powder, usually about 60gr or so is enough to send a flare up to about 400ft. When we were first doing loading experiments for 40mm, the worst that happened is the projectile got stuck in the barrel, we never once had anything resembling an explosion (FYI, these were test projectiles) as the result of not having enough powder in the case, also, these cases are plastic, which would make an explosion glaringly obvious. If there wasn't enough powder, nothing would ignite properly, and it would result in unburned powder fouling the gun.

Now, as to what probably caused this guys gun to blow up... The top two culprits are going to be bullet setback, and overcharge. Most novice reloaders don't pay enough attention to the crimp, and this is especially true of novice commercial reloaders (there are a lot of these out there). When I'm setting up a press, I destructively test cartridges for crimp, this is done by putting them in a press, and seeing how much force it takes to move the bullet a set distance. For .45 and 9mm... it's a lot more force than you might think.

There is one other possibility, and that is, the machine was set up for bullets of one weight, and a bullet of a different weight got mixed in. In my experience this happens frequently, and is actually a huge problem if you're not paying attention. On the Ammoload and Camdex machines, a bullet of the same caliber, but of different weight/size will usually jam the machine, however if someone's pulling the handle on a dillon, they may not notice. In the case above, it's quite possible the whole box of ammo suffered this defect, and the over-pressure simply took a number of rounds to eventually blow up the gun.

Based on my experience, the myth of the "underloaded case" is just that, it doesn't result in detonation, but it may result in squib at which point it most certainly will blow up the gun.

 

[tac]

Groat paste!

With your persimmon, I'd like to repoast it on a forum over here in yUK.

tac

 

[AMProducts]

By all means.

 

[tac]

TVM.

BTW, you ARE up early!

tac

 

[The Heretic]

I do light loads (rifle and handgun) with fast powders (usually bullseye) and dacron loaded on top of the powder to hold it in place against the primer - not so much because of fear of detonation, but rather because I want consistency in how the powder burns regardless of the position of the firearm. I usually use cast bullets for these, although I have loaded light jacketed bullets too.

Never had any problems, don't expect to.

I didn't read the whole thread, but just throwing this in the pot.

Now that Trail Boss is out there, if I can ever find any, I will use that instead.

I can't think of a reason to use a light load of slow powder for my purposes - especially in a large case.

YMMV