[benzy2]

Anyone have any cases where a round detonated due to too light a load? I have always loaded within what the data I have claims to be safe but I was just wondering if anyone has ever seen a case where the round was known to be underloaded and caused a failure. Some people act like a 0.1gr below listed MIN will blow the rifle up and yet Hodgdon suggests to load H4895 down to 60% MAX which is far lower than any starting load. Any solid data that too little powder blew a round up?

[Clarence]

35 years ago when I first got started reloading I read articles about the mythical "detonation". I've never seen any empirical evidence that it occurs, but I don't worry about it.

If you want to load light loads use the appropriate powder. If someone wants to load plinking loads they shouldn't be using 4831.

Just my .02

[ants]

From the articles I found, detonation is suspected when using extremely small loads of extremely fast powder (shotgun powder), not light loads of a proper rifle powder.

For safe light loads with rifle powders, go to powder/bullet manufacturer's published data and look up youth loads (or managed recoil loads).

[rcmodel]

It is not a true "detonation".

And it always happens with over-bore calibers and very slow powder.

4895 does not qualify as a very slow powder.

My belief is, true detonations do not take place, because they can't.
A super-sonic detonation pressure wave cannot be supported in a small quantity of smokeless powder.
If it could, you could place a blasting cap in an 8 pound drum of H-4831, or any other smokeless powder, and have yourself a very powerful bomb.

But you can't because small quantities of smokeless powder will not detonate. They will only burn.

My theory of what blows up rifles with reduced charges of slow powder is this.
1. Primer fires, perhaps flashing over the reduced charge instead of burning through it from the rear and lighting a lot of it at once.
2. Moves Bullet into the rifling.
3. Slow powder has not built up sufficient pressure yet to keep the bullet moving.
4. Then it does, and the stuck bullet is a bore obstruction right in front of the chamber.
5. KaBoom!

It was simply a bore obstruction blow-up, not a detonation.


As for fast pistol powder light loads detonating?
No way.
Again, powder will not support a detonation wave, or you could make powerful bombs out of one pound cans of Bullseye.
You can't.

A small charge of fast pistol powder does not contain enough stored energy to blow up a gun.

People blow up light loaded pistols by stuck bullets, or double charging.

rc

[jerkface11]

What blows up rifles with reduced charges is this.
1. Primer fires
2. Moves Bullet into the rifling.
3. Slow powder has not built up sufficient pressure yet to keep the bullet moving.
4. Then it does, and the stuck bullet is a bore obstruction right in front of the chamber.
5. KaBoom!


That's total nonsense.
You can't show me a single case where someone blew up a gun using a slow powder. People claim "detonation" when they tried using a little bit of a fast powder and double or triple charged a case.

[ReloaderFred]

Years ago, the NRA commissioned the H. P. White Laboratory to try to prove or disprove detonation in the .38 Special, using light loads of Bullseye powder and HBWC bullets, since that's where most of the stories originated from. H. P. White was unable to make detonation happen, and they spent considerable time and effort trying. The final determination was that double and triple charges of Bullseye were the culprit, not detonation.

As for rifle detonations, I don't recall any definative testing being done, but that's not to say that it hasn't been investigated at length. I just don't recall reading anything about it, but I do specifically remember the NRA tests.

Hope this helps.

Fred

[rcmodel]

That's total nonsense.It's well known if you care to read the history of over-bore wildcatting and magnum caliber load development.

It's only nonsense if you are uninformed.

rc

[jerkface11]

Sure it's very well known. Now provide some evidence. You can't blow up a gun with a little slow powder. I've used too little IMR 5010 before. It simply didn't ignite fully. No explosion. Guns blow up when you use too much powder.

[rcmodel]

Read P. O. Ackleys books.

It is covered in detail.

Alliant at one time published a small pamphlet covering reduced load pistol powder blow-ups. They couldn't make it happen BTW.

rc

[jerkface11]

Ok so no evidence other than 70 year old anecdotes. You must be right!!!

[Mal H]

This topic comes up in two year increments.

The 2007 installment: http://www.thehighroad.org/showthread.php?t=244858

The 2005 installment: http://www.thefiringline.com/forums/showthread.php?t=163195

I'm not going to comment on it any further than I did in those threads. It seems if you believe you know what happened as verified by a very reputable writers using valid testing methods, you're as crazy as they are. (rcmodel - join the club!)

[Doug b]

Rcmodal the army did some testing at Aberdeen with artillery rounds and drew the same conclusion as you.The powder ignites after the projectile comes to a complete stop.Obstructed bore.It's on the net somewhere but I don't remember the link and don't have the time now to find it.You are correct as usual.

[rcmodel]

There is a write-up about it on page 62 - 63 of the Speer #13 reloading manual.

Along with the caution not to reduce loads of slow-burning powder (Slower then IMR-4350) below the starting loads listed in the manual.

Also a warning on page 53 of the Hornady #4, and page 72 of Hornady #6 about reducing loads of slow powder below the starting loads listed.

Everyone doesn't agree on the cause, but they all agree it is dangerous.

rc

[Walkalong]

Something happens from time to time that defies concrete explanations. :uhoh:

[USSR]

Funny, how in the pre-Internet days this was common knowledge among nimrods, and now must be learned all over again by those not exposed to the writings of the gun scribes of that era.

Don

[DesmoDucRob]

I've always been interested in this, but never (and still don't) completely understand it. I've now got a few cited sources to start with. I don't make a habit of taking internet offerings as gospel, but I will follow up on published data when it is recommended. See you folks again in 2011;)

[rcmodel]

See first sentance, second paragraph for another clue:

http://www.hodgdon.com/PDF/Youth%20Loads.pdf

rc

[ants]

Are we confusing detonation with overpressure? He asked about detonation.

Modern gunpowders are formulated to burn in a controlled manner in order to accelerate a projectile with accuracy. High explosives burn supersonic and create a shockwave that causes damage. I believe the OP was asking about the theory that gunpowders may detonate like an explosive under certain conditions: "Actual proof of detonation?". Detonation is commonly called 'Secondary Explosive Effect' among internet forums, and called 'Pressure Excursion Phenomenon' in the firearms industry. I don't find any reference that it has ever been demonstrated in controlled conditions.

I don't think he's asking about overpressure, which needs no proof. Idiots blow up their guns with too much powder every day. That act is patently empirical.

[Ol` Joe]

There has been some evidence of a secondary pressure excursion in rifles with slow powders and light bullets. Gun maker Charlie Sisk has found evidence of it in one of his rifles and recorded it with a pressure trace. He reported on it on the 24hourcampfire and had a couple gun writers report they have seen similar pressures in their use of pressure measuring equipment. I couldn`t find the original thread of Charlies but it is referanced here.
http://www.24hourcampfire.com/ubbthreads/ubbthreads.php?ubb=showflat&Board=34&Number=578377&Searchpage=11&Main=60032&Words=%28%26quot%3Bsecondary+pressure%26quot%3B%29+%28%26quot%3BMuzzle+brake%26quot%3B%29+%28%26quot%3Bpressure+spike%26quot%3B%29&topic=0&Search=true#Post578377

[Clarence]

All the reading I've done on the subject involved extremely light charges of slow burning powder in large cases. P.O. Ackley addressed this at length as has already been mentioned, and I also remember reading an article by Jack O'Conner on the same subject. It also seems like Warren Page weighed in on the issue at some point.

Sorry if that doesn't jive with everyone who already has their mind made up on the issue.

[jerkface11]

You aren't going to blow up a rifle with ANYTHING other than a pistol powder.

[Beagle-zebub]

Ok so no evidence other than 70 year old anecdotes. You must be right!!!

Yep. Sorta like nuclear warfare.

[Sport45]

You aren't going to blow up a rifle with ANYTHING other than a pistol powder.

That, sir, is just not correct.

[jmorris]

Many of the considered “safe” reduced (subsonic) rifle loads use pistol powders.

[jerkface11]

That, sir, is just not correct.

Ok then prove it. The OP asked for actual proof.

[depoloni]

I've over-reduced a charge before when speculating for a wildcat with no real load data available and had gas escape into the breech due to insufficient case expansion. Never a detonation though, so I can't offer proof.

Of course, offhand, I generally take the experts consensus (proof or not - imagine that!) about what's generally a bad idea versus a great one. If several different load manuals caution against light loads in big cases with slow powder, well, I guess you can call me a mindless sheep.

Seems like a good enough reason to this wooly bugger to choose another powder and/or load combo rather than take the chance. I'll continue to lose sleep at night over what I may be missing out on following those proofless recommendations, but such is life. ;)

[fireman 9731]

There is a big difference in a blown up rifle from a "detonation" and an "over-pressure".

Is "detonation" possible with any load of any powder in any cartridge?

No. Absolutely not.

Powder burns, even under intense heat a pressure. It wont "detonate".

A primer "detonates". Which just means that it burns faster than the speed of sound, with an accompanying pressure wave.

Fill a cartridge with primers and you might detonate your rifle.
Fill a cartridge with any combination of powder and you might create an over pressure that "blows up a gun", but detonation simply can't be achieved with normal rifle, pistol, or shotgun powders.

[fguffey]

and powder is not position sensitive? then there are those that charge the case with powder then add a filler to keep the powder packed to the rear (laying) or bottom (standing), could be two reasons.

Norma did not spend a lot of time talking about it basically they said it is difficult to duplicate, they did not said it would happen, they said it could happen, then they quit talking about it.

Position of powder, raise the pistol/rifle straight up, lower to level, fire, the powder is in a heap in front of the primer with a small area exposed to the flame, good/bad? I would say on the side of good, if powder is position sensitive.

Position of powder, lower pistol/rifle straight down, raise to level, fire, the powder is is in a heap behind the bullet and is as far as it can get from the primer, again, in a heap, the powder has a small area exposed to the flame, good/bad? I would say this condition is in the middle, if powder is position sensitive.

Position of powder, level the pistol/rifle, shake the rifle to level the powder, fire, the powder in the case is laying in the bottom (laying) from the primer to the bullet and has a large area exposed to the flame, in this configuration the powder will burn more efficient (faster) than powder piled in a heap./

Just for fun, load a case with primer and bullet, no powder, chamber and fire, do this with different primers to determine which primer drives the bullet into the barrel the greatest distance , (just in case someone ask what you are doing). Now consider the position of the powder, if the primer is fast and has enough energy to drive the bullet out of the crimped case and in to the barrel, and, if the powder burns slower (or not as fast) the bullet could stop and require another start as pressure builds, the question now is, can the bullet start moving before the pressure exceeds the ability of the pistol/rifle to contain the pressure.

There was an attempt to save money by using reduced loads in the Low Number Springfiled, must have been a bad ideal the practice was stopped, seems there was a problem with shock, the LN was to brittle to absorb the shock, the pieces did not fly far, seems the receiver was left in a heap, meets and or exceeds?

Careful with Federal primers, they are more dangerous and powerful.

Detonation, two flame fronts, if we are talking about the internal combustion engine. Two different sources of ignition. The primer is the (one) sources of ignition when talking about ammo, I do not use reduced loads, I do not put my money on the bullets ability to get out of the way before the pressure builds and exceeds the pistol/rifles ability to contain it, as Norma said, it can happen, then they quit talking about it.

F. Guffey

[Walkalong]

I have not played much with rifle powders and how position sensitive they are, but I have with pistol powders.

Some are SEVERELY position sensitive and don't need to be used in loads with a lot of air space. I can only assume the possibility that some some rifle powders are the same way.

What problem it will cause in rifles, I don't know. I have not been brave enough to try it.

I believe double and triple charges blow up pistols. I am not so sure about rifle calibers and I don't download them except for proven methods.

[Sport45]

Quote:
That, sir, is just not correct.

Ok then prove it. The OP asked for actual proof.

Are you kidding? Tell ya what. I don't care to damage any of my guns so why don't you go out and buy a large case magnum rifle. I really don't care which one. Fill a case for that rifle with IMR4227 (The "R" stands for rifle, Improved Military Rifle to be precise) and load a heavy-for-caliber bullet over it. Take it to the range an touch it off. Maybe you can prove me wrong that way.

I suppose I could have saved a lot of trouble if instead of my first post I had put in something like this:

You aren't going to blow up a rifle with ANYTHING other than a pistol powder.

Okay then, prove it!