Actually if you read Keith Applegateon's observations [here again]:
[See mid page posting at 19 Feb 2010 at 2:41 am]
http://www.thefirearmblog.com/blog/2009/11/20/colt-ar-15-kaboom/
.... you will see he discounts the <<Min 296/110 Kaboom theory
Ok, so I got the manuals, and now I'm confused
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[See mid page posting at 19 Feb 2010 at 2:41 am]
http://www.thefirearmblog.com/blog/2009/11/20/colt-ar-15-kaboom/
.... you will see he discounts the <<Min 296/110 Kaboom theory
denton
Member
Rifle explosions with reduced charges of slow burning powder are well documented, but infrequent.
I know something about Brownell's equipment, and it had significantly greater bandwidth (ability to respond to fast signals) than equipment commonly used to measure pressure today. He could see fast events that commonly used equipment misses.
He was able to show that with reduced loads of slow powder, the pressure curve was "spikey". That is, there were very fast, large pressure events riding on the usual pressure curve. The info was published in the early 70s.
The events are probabalistic and individually unpredictable. However, we can make some statements about how often the stars align to produce destructive pressure. Shoot enough half-case charges of 4831 in your 270, and you will disassemble it, without a doubt. S.E.E. is real and documented.
I know something about Brownell's equipment, and it had significantly greater bandwidth (ability to respond to fast signals) than equipment commonly used to measure pressure today. He could see fast events that commonly used equipment misses.
He was able to show that with reduced loads of slow powder, the pressure curve was "spikey". That is, there were very fast, large pressure events riding on the usual pressure curve. The info was published in the early 70s.
The events are probabalistic and individually unpredictable. However, we can make some statements about how often the stars align to produce destructive pressure. Shoot enough half-case charges of 4831 in your 270, and you will disassemble it, without a doubt. S.E.E. is real and documented.
MEHavey
Sorry I missed you pointing to that cretin post. I read down to & most of his post.
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Denton
I don't know anything about 4831 or do I have a 270 but from looking at the burn chart it looks like a prime example of what I was saying above. It is so slow that by the time you get the pressure up for correct combustion all of a sudden its to much. I've read that these are the most accurate powders but it's like playing Black Jack you take it as close as you can but when you bust it's game over. I have powders like this but I don't use them because I'm smart enough to know it is out of my league for now.
I use Fast powders where almost all of the expansion is done in the chamber & barrel & buy the time the bullet leaves the barrel all of the energy as been transferred to the bullet. That way Newtons' 3rd Law is take by the rifle & not my shoulder.
Sorry I missed you pointing to that cretin post. I read down to & most of his post.
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Denton
I don't know anything about 4831 or do I have a 270 but from looking at the burn chart it looks like a prime example of what I was saying above. It is so slow that by the time you get the pressure up for correct combustion all of a sudden its to much. I've read that these are the most accurate powders but it's like playing Black Jack you take it as close as you can but when you bust it's game over. I have powders like this but I don't use them because I'm smart enough to know it is out of my league for now.
I use Fast powders where almost all of the expansion is done in the chamber & barrel & buy the time the bullet leaves the barrel all of the energy as been transferred to the bullet. That way Newtons' 3rd Law is take by the rifle & not my shoulder.
But if you did, you would find makes a near ideal 130gr/270Win combination. Right up there w/ RL-19 and AA4350
Complete case fill/burn and 3,000++fps for 55,000psi in a standard 24" barrel
IMR4831 is the under-appreciated star of the 30-06 family of cartridges, and points to the fact that (even slow) powder speed is a significant factor in tailoring the most performance in what is a ballistic system of systems.
But the OP was worried about excessive case space, and you are correct that fast powders work well in those instances, but at the expense of reduced velocity for a given pressure.
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But if you did, you would find makes a near ideal 130gr/270Win combination. Right up there w/ RL-19 and AA4350
Complete case fill and 3,000++fps for 55,000psi
(IMR4831 is the under-appreciated star of 30-06 family cartridges.)
You are correct, however, that the OP's concern for excessive free space above the powder is best addressed by using fast powders. But that flexibility comes at some cost in velocity for a given pressure.
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Lost Sheep
Member
Question resolved?
But the OP's quest is for a velocity outside (below) those found in most common loading manuals. Hence the dilemma and the search for more flexible powders (which, unless you deny the existence of S.E.E. or "flashover" pressure spikes) almost invariably consists of faster powders.
Lost Sheep
So, that is why one selects a bullet and velocity first, then consults loading manuals to find a powder that delivers that velocity within a pressure range that has been lab tested.
But the OP's quest is for a velocity outside (below) those found in most common loading manuals. Hence the dilemma and the search for more flexible powders (which, unless you deny the existence of S.E.E. or "flashover" pressure spikes) almost invariably consists of faster powders.
Lost Sheep
"So, that is why one selects a bullet and velocity first, then consults loading manuals to find a powder that delivers that velocity within a pressure range that has been lab tested."
Actually I find a bullet that works for the twist rate then I select a powder & find the minimum amount of powder it takes to get it ourt of the barrel then check groups up to where it shows pressure signs. I then take the best groups that at the speeds that make the bullet do what I want it to(frag or penetrate). I just recently got a chrono before I was using water bottles. I rarely find data for anything I load & have to develop my one. I don't know PSI but I can tell a case hard to extract. Most of my cartridges could be reloaded without resizing.
Actually I find a bullet that works for the twist rate then I select a powder & find the minimum amount of powder it takes to get it ourt of the barrel then check groups up to where it shows pressure signs. I then take the best groups that at the speeds that make the bullet do what I want it to(frag or penetrate). I just recently got a chrono before I was using water bottles. I rarely find data for anything I load & have to develop my one. I don't know PSI but I can tell a case hard to extract. Most of my cartridges could be reloaded without resizing.
Sunray
Member
"...Neither manual has..." Hi. That's because the bullet and powder maker's books only have data for their products. Fortunately, it doesn't matter. You load for the bullet weight, not a particular maker's bullet. A 148 grain WC is a 148 grain WC.
"...us black powder folks..." You load in grains, but by volume. Smokeless is loaded by weight.
The manuals give slightly different data because the reflect the conditions on the day of the testing. This includes the firearm used(that may be a universal receiver) and the powder lot.
"...us black powder folks..." You load in grains, but by volume. Smokeless is loaded by weight.
The manuals give slightly different data because the reflect the conditions on the day of the testing. This includes the firearm used(that may be a universal receiver) and the powder lot.
denton
Member
Possibly not the wisest course of action.
Pressure signs generally do not become apparent until about 70,000 PSI. Primers fall out around 80,000.
http://www.shootingsoftware.com/ftp/dbramwell%20july%2019%2004.pdf
Sorry for the hijack of the thread....
It's been an interesting thread. Thanks to all who posted.
To realign a bit: I'm starting to reload smokeless pistol cartridges to save some money. I believe in keeping proficient with my carry gun, and that means practice, practice, practice. So far, that's about 4000 rounds a year but I'm going to up that by another 1000 by changing my routine this summer. So, economically it makes sense to roll my own.
I do not intend to start experimenting with different bullets and powders, at least not in the foreseeable future. My favorite practice round is a .38 special 148 gr HBWC reload bought locally. I intend to reproduce that round, nothing more. I will use standard reloading manual loads, right out of the book and let you guys more interested in the science do the experiments.
But reading the manuals leads to some interesting questions for a guy schooled in black powder axioms. I think those have been answered so far - the 148 gr HBWC can be loaded into a .357 case but only to .38 special loads, otherwise the bullet may come apart. And the extra empty space is not a problem with powders like HP-38. (I realize I'm generalizing here, and probably over-simplifying, but hey, I'm new at this)
BTW, I don't intend to load .357 brass with 148 gr HBWC's; it was just a question about the manual presentation. I do use full up .357 magnums in my practice routine, and they will become part of the reload scenario in the future. But again, it will be to a standard reloading manual bullet/powder combination, chosen to match my practice rounds, and eventually even my SD carry rounds.
Thanks, guys, you've been a big help. Hope I can return the favor over on the dark side someday.
To realign a bit: I'm starting to reload smokeless pistol cartridges to save some money. I believe in keeping proficient with my carry gun, and that means practice, practice, practice. So far, that's about 4000 rounds a year but I'm going to up that by another 1000 by changing my routine this summer. So, economically it makes sense to roll my own.
I do not intend to start experimenting with different bullets and powders, at least not in the foreseeable future. My favorite practice round is a .38 special 148 gr HBWC reload bought locally. I intend to reproduce that round, nothing more. I will use standard reloading manual loads, right out of the book and let you guys more interested in the science do the experiments.
But reading the manuals leads to some interesting questions for a guy schooled in black powder axioms. I think those have been answered so far - the 148 gr HBWC can be loaded into a .357 case but only to .38 special loads, otherwise the bullet may come apart. And the extra empty space is not a problem with powders like HP-38. (I realize I'm generalizing here, and probably over-simplifying, but hey, I'm new at this)
BTW, I don't intend to load .357 brass with 148 gr HBWC's; it was just a question about the manual presentation. I do use full up .357 magnums in my practice routine, and they will become part of the reload scenario in the future. But again, it will be to a standard reloading manual bullet/powder combination, chosen to match my practice rounds, and eventually even my SD carry rounds.
Thanks, guys, you've been a big help. Hope I can return the favor over on the dark side someday.
denton
Member
Sounds like you are on the right track and I would expect that this will work out well for you.
I have converted practically all of my shooting to cast bullets for economy.
I'm not very familiar with HP-38. It may be the ideal powder for all I know.
Watch for excessive sootiness. The lower the pressure of the round, the more soot it seems to generate. Also watch for position sensitivity (different results when the muzzle is lowered into position vs. raised).
In my guns, TiteGroup and Universal have tested position insensitive, and Universal seems to generate the least soot.
Of course, a little soot probably wouldn't matter to a BP shooter....
I have converted practically all of my shooting to cast bullets for economy.
I'm not very familiar with HP-38. It may be the ideal powder for all I know.
Watch for excessive sootiness. The lower the pressure of the round, the more soot it seems to generate. Also watch for position sensitivity (different results when the muzzle is lowered into position vs. raised).
In my guns, TiteGroup and Universal have tested position insensitive, and Universal seems to generate the least soot.
Of course, a little soot probably wouldn't matter to a BP shooter....
The only cases I have ever had hard to extract Has ether been using listed data & factory rounds. As for my favored rounds that there is no data foe still has somewhat rounded primers & some neck tension. I think I can survive on my wisdom but thanks for the concern.
Also let me add I have found for myself the best groups come from the lower pressure loads.
My practice scenario does not include lowering the muzzle onto the target, although maybe it should - I practice drawing from a strong side carry, raising the muzzle up to a two hand hold front sight on target. So I probably won't see any position sensitivity. I'll consider that, though.
Soot? What's soot?
Soot? What's soot?
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