There is an incident described in Hatcher's Notebook where he was trying to remove a barrel obstruction by firing a bulletless cartridge. The powder ignited, and was trapped in the barrel until the bolt was opened. That is the type of energy I am referring to. The powder gas expanded, but there was not enough stored energy to cause the rifle to blow up. Had there been a detonation, I think the rifle would have been destroyed.
When you have a detonation, there is a shock wave, and this is just my opinion, but if a small amount of powder is the cause of the blow up, it is because of the shock wave that is produced and not the force of the explosion.
The way a shock wave is produced, under certain conditions, instead of an expansion of powder gases, which is the normal function of gun powder when it is ignited and used as a propellant, is beyond my field of knowledge.
The extent of damage caused by an explosion from gunpowder is limited to the bursting of the container, in the event the pressure exceeds the strength of the container. What this means is, you couldn't blow up a building with gunpowder, unless you some how caused it to detonate.
Solids like wood, for example, don't burn as solids until initial heat converts 'em to gas.
Ken So the thought is the powder is "boiling off" sort of like gasoline and its vapors that will ignite violantly once they have reached a certain density?
Bob, that smith wouldn`t be Bruce?
Last edited by Ol` Joe; 04/29/08.
I must confess, I was born at a very early age. --Groucho Marx
Patriotism is supporting your country all the time and your government when they deserve it. --Mark Twain
Well there you go. From the discussion above looks like its going to remain a "mystery" for a lot of us for some time to come. Lots of conjecture but very little scientific fact.
Further in Hatcher's Notebook he describes an explosion caused by shooting into a large container of smokeless powder. Whether detonation or really fast deflagration it must have been impressive! S.E.E. may well describe a detonation, I don't know, but I do know I don't want it (detonation being generally described as producing shock wave propagating faster than the speed of sound).
The point is that the rate of liberation of energy is often more important than the amount of energy. Ferinstance a rifle cartridge filled with a slow powder like 4831 may be just dandy. Fill it with Bullseye and it's a pipe bomb - Bullseye releases about the same amount of energy but a whole lot faster, but does not detonate.
The key elements in human thinking are not numbers but labels of fuzzy sets. -- L. Zadeh
Found the article on a website. Copyright warning there also. Should I just give link, or whole page, appears to be public website.
This article made sense to me, one who has no ballistic, thermodynamic background.
To me he is saying detonation is possible with some pistol powders according to the igniability (not the RQ) of a particular powder in relation to the 'system' limits.
This would explain some of the strange occurences I've been hearing or picking up on with Lil'Gun in some cartridges. A relative new powder, and folks doing things with it, it was not intended for.
Has SEE ever been recorded when using ball powders?
Shew me thy ways, O LORD: teach me thy paths. "there are few better cartridges on Earth than the 7 x 57mm Mauser" "the .30 Springfield is light, accurate, penetrating, and has surprising stopping power"
I use Greg�s data in several cartridges and it works very well for me. When using fast powders in large cases extra care is required in loading. Alliant Bullseye and Accurate Arms No. 2 work well in large cases. I have shot his .218 Bee, .25-20 and .25-35 data extensively in my rifles and my data has parallel his.
Not sure, but I think a shock wave reaches about 20,000 FPS, and another property it has is that it is very difficult to stop, if it can be stopped at all.
This ability to try to keep going, no matter what it comes in contact with, is the reason a shock wave is so destructive.
Solids like wood, for example, don't burn as solids until initial heat converts 'em to gas.
So the thought is the powder is "boiling off" sort of like gasoline and its vapors that will ignite violantly once they have reached a certain density? �
Please excuse me, my friend � I'm simply not interested in taking part in a long, drawn-out discussion of this.
"Good enough" isn't.
Always take your responsibilities seriously but never yourself.
always use ninety to a hundred percent of a case-filling charge of your optimum powder
How is "optimum" defined in this sense? Is this basically saying use any powder which lets you fill the case without raising pressures higher than acceptable? Does this work for even big black powder cases, which must keep pressures down in the 20's?
I wondered when someone would mention Greg's work. Based on Greg's data, I load 11 grains of Unique and NO FILLER under a 400 grain cast bullet in my 45-70s for about 1000 fps and extreme accuracy. Load density is extremely low - like less than 10%. The powder supposedly detonates, but maximum pressure is limited by the small amount of fuel (powder) in the case. Whatever the reason, it works. I can shoot these loads all day long without discomfort, and so can my 11-year-old son.
Again, this load is to be used with NO FILLER.
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Our God reigns. Harrumph!!! I often use quick reply. My posts are not directed toward any specific person unless I mention them by name.
� always use ninety to a hundred percent of a case-filling charge of your optimum powder
How is "optimum" defined in this sense? Is this basically saying use any powder which lets you fill the case without raising pressures higher than acceptable? Does this work for even big black powder cases, which must keep pressures down in the 20's?
That's right.
"Good enough" isn't.
Always take your responsibilities seriously but never yourself.
Here are two graphs from Brownell's work that bear on the issue. One shows a "spikey" pressure curve that he observed, and the other shows powder charge vs. pressure for 3031. Note that below about 30 grains of powder, the variability of the pressure increases greatly, and that one 20 grain charge produced an unusually high pressure.
I think Bob Greenleaf, formerly of Savage, did an article on this in Handloader several years ago. He was of the opinion that it was due in part to erosion of the throat, causing the bullets to grab, then skip, then grab again (paraphrasing, obviously) which was causing pressure spikes, sometimes using wholly appropriate powder charges and bullets, just in highly eroded bores. It was a very interesting article, but I gave it to a cousin who was having difficulties with a worn .243 at the time, so I can't access it.
You can roll a turd in peanuts, dip it in chocolate, and it still ain't no damn Baby Ruth.
I believe the article you are thinking of is; "Mystery Solved," Charles E. Petty, Handloader 187, June-July 1997. This was about PMC and their experiences blowing up a 6.5 X 55 rifle and then blowing the same barrel off their pressure gun. I wrote Dave Scovill about this article and told him I thought it was the article of the decade. Dave wrote back, nice fellow, but I don�t recall what he said.
