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Post by whyohe on Jan 8, 2010 20:08:07 GMT -5
VERY well put ET. I see now. Once you get the initial burn pressure(wich would be light in general pressure) and the bullet and un burnt powder moves forward, it burns like a cannon fuse just WAY faster, millisecond. this creates the forward pressure wave.
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Post by ET on Jan 8, 2010 20:39:58 GMT -5
VERY well put ET. I see now. Once you get the initial burn pressure(wich would be light in general pressure) and the bullet and un burnt powder moves forward, it burns like a cannon fuse just WAY faster, millisecond. this creates the forward pressure wave. You got it, what I was trying to express. Ed
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Post by pcgolfer on Jan 9, 2010 22:07:53 GMT -5
Yeah a guy in Canada blow some of his fingers off. I saw the pics..... looked pretty bad. BTW, the hunter was new to muzzleloading. I am going to go with user error. Something like powder, sabot, bullet.... another round of powder, sabot, bullet. If I read Randy's post that would put pressures up to 300,000 psi... the savage has been tested to 125,000. Our loads are 40,000. Putting it another way, the Savage is better able to handle this type of error than any other gun built. Like it or not, There is no production muzzleloader that even comes close.
People really need to use the ramrod as verification of a seated bullet every single time... no exceptions. Like most guns, if the stock ramrod is flush with th barrel... gun empty. I have mine marked for a loaded round... if it is on that line... green light. Anything other than that, and the breechplug is coming out. No way I am firing it. This is very simple to do... also too easy to skip.
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Post by youp50 on Jan 14, 2010 10:22:39 GMT -5
Two thoughts.
Is this the same guy in Canada that blew up the ML while loading it? I remember some guy in Quebec, his wife said he was hammering it in the house, I dunno...
Pressure waves. Look at the bottom of a used sabot. It is full of little indentations. Only thing I can figure is they are from un-burned powder grains. Maybe some kind of jet effect? Some more of that I dunno...
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Post by rossman40 on Jan 14, 2010 11:52:39 GMT -5
I attended a seminar/class one time and the main theme was the deflagration to detonation transition of the propellant train. The guy that was the speaker was this Einstein looking german or russian dude and while he seemed to know his stuff, put most of the explanation over our heads. Basicly the pressure wave of the intial deflagration intiates the detonation of the rest of the charge due to compression by the shockwave. Shockwaves were discussed and how they were a important part of the "burn", I think the word used was propagation. It was also discussed that with reduced volume charges in a large chamber the shockwave could reflect off the base of the projectile and come back into the reaction zone and actually increase pressures. How powders react in say a 40,000lb chamber pressure condition compared to say a 150,000lb is totally different. There was something about with triple base powders which uses large amounts of nitroguanidine the higher the pressure of the shockwave it can shatter the cyrstaline structure on a molecular level releasing energy even faster.
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Post by youp50 on Jan 14, 2010 12:29:46 GMT -5
Rossman,
You just never cease to amaze me.
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Post by DBinNY on Jan 14, 2010 13:05:57 GMT -5
Thanks Rossman, that clears it up for me
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Post by wilmsmeyer on Jan 14, 2010 13:51:22 GMT -5
I'm positive that Rossman has a secretary....and her name is Money Penny
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Post by ozark on Jan 14, 2010 16:35:08 GMT -5
I know little about Rossman. I do know that he has all his ducks in a line. Sometimes his comments are over my head but I learn things from him.
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Post by wilmsmeyer on Jan 14, 2010 18:55:07 GMT -5
Ozark...he's a secret agent....for us!
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Post by minst7877 on Jan 14, 2010 19:38:19 GMT -5
I attended a seminar/class one time and the main theme was the deflagration to detonation transition of the propellant train. The guy that was the speaker was this Einstein looking german or russian dude and while he seemed to know his stuff, put most of the explanation over our heads. Basicly the pressure wave of the intial deflagration intiates the detonation of the rest of the charge due to compression by the shockwave. Shockwaves were discussed and how they were a important part of the "burn", I think the word used was propagation. It was also discussed that with reduced volume charges in a large chamber the shockwave could reflect off the base of the projectile and come back into the reaction zone and actually increase pressures. How powders react in say a 40,000lb chamber pressure condition compared to say a 150,000lb is totally different. There was something about with triple base powders which uses large amounts of nitroguanidine the higher the pressure of the shockwave it can shatter the cyrstaline structure on a molecular level releasing energy even faster. Still trying to get my brain around this. Not sure if it ever will fit.
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Deleted Member
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Post by Deleted on Jan 14, 2010 22:01:50 GMT -5
This part of Rossmans statement raised a question for me...
"It was also discussed that with reduced volume charges in a large chamber the shockwave could reflect off the base of the projectile and come back into the reaction zone and actually increase pressures."
Could this be the reason that if a sabot/bullet is moved off the powder charge a short distance down the barrel and then ignited there is an increased chance of bulging or bursting a barrel?
The combustion chamber is definately made larger in that case.
Just wondering....Zen
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Post by rossman40 on Jan 15, 2010 19:15:51 GMT -5
I always thought powder burn was pretty simple till I went to Field Artillery University (Ft. Sill) and Aberdeen. If you look at the propellant train the primer goes off and injects hot gases and particles thru the vent which ignites the powder and starts deflagration. The difference between deflagration and detonation is the burn rate, a subsonic (1125fps or less) burn rate is deflagration, a supersonic burn rate is detonation which propagates by shock compression. Now the burn rate of smokeless powder, even double base, approaches no where near what say C4 does (28,000fps), the burn rate is controlled by additives which keeps it below a full blown instantaneous detonation. As deflagration starts pressure increases and with smokeless powder as pressure increases so does the burn rate. Now in the first .1 millisecond the pressure is enough to start pushing the sabot and about .3 to .5 milliseconds you reach peak chamber pressure but you have to remember that your sabot has already started moving so your chamber is increasing in size, your now on the downside of the pressure curve. As far as the primer just igniting the base of the powder column and push the charge forward, not necessarily true. A interesting experiment would be to put a piece of say styrofoam into the barrel over the breechplug, set a bullet on top of it and pop a primer. You could then slice the styrofoam and examine the burn and how far particles were injected. A few neat articles, good reading that your taxpayer dollars paid for, www.arl.army.mil/arlreports/2007/ARL-TR-4188.pdfwww.arl.army.mil/arlreports/2009/ARL-TR-4903.pdf. Big guns use a ignitior tube thru charge much like the hole thru Pyrodex or T7 pellets. If the charge was forced against the base of the sabot and then burned the sabot would be toast. I have seen where guys were shooting three Pyrodex pellets and the third pellet goes downrange like a fireball. This could be a result of crushing the lower pellets. As far as the shockwave from the propagation of the burn this would be almost impossible to measure and more theory to model. This isn't the same as chamber pressure or the pressure wave the bullet/sabot is riding. Mr Broemels modeling of burn rates to calculate chamber pressures in his Quickload program is a big step forward. Supposedly the Army's Ballistic Research Lab (BRL), now the Army Research Laboratory (ARL), has some hi-speed modeling programs they are using to try to figure out what is happening and how to make things better. Even TB has found just switching between different styles of Knight breechplugs can effect the burn of BH209. With the 10ML we deal with a sabot so we do not have to deal with bullet crimps and the resistance of engraving the bullet into the lands as do centerfires. I read in one article it takes 12,000 psi to engrave a M855 bullet into the rifling in a M16. We should never have space in the combustion chamber which you have to deal with using a case. I often think about the unexplained bulges. The thing that gets me is most happen with 5744 which is a double base powder heavy with nitro. If you lift the bullet off the powder or get a delayed burn could the shockwaves increase the burn rate which in turn would increase chamber pressures which would then also increase burn rate perhaps to the point where the deterrents added to the powder to slow the burn rate do not work. People have done experiments to try to duplicate (RB for one) but so far there is no answer or proof. There was a article, www.charm.net/~kmarsh/burn.htmlI often think we are just a bunch of muzzleheads who spend too much time in a tree stand coming up with questions. If we had a nice lab/workshop, unlimited budget, a couple of Crays to do simulation modeling, we would be downright dangerous.
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Post by button buck on Feb 7, 2010 13:39:38 GMT -5
Give me an e-mail on the savage rrmr270@aol.com thanks i am also new
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Post by rossman40 on Feb 8, 2010 10:29:08 GMT -5
What do you want to know? What we are discussing here are advanced safety issues against claims of danger. Also to get a better understanding of the mechanics involved. Myself I think of the thousands of shots taken yearly by shooters using proper loading techniques and safety procedures and have no fear. Hopefully the claims just serve to make the shooter be more vigilant on his technique and procedures.
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