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Hot Topic (More than 10 Replies) ball powder for original pope (Read 1925 times)
critter68
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Re: ball powder for original pope
Reply #15 - Sep 7th, 2022 at 8:55pm
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Thanks joe. That was shot with my miller in 32ms. 4100 for powder.
Mike
  

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Cbashooter
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Re: ball powder for original pope
Reply #16 - Sep 8th, 2022 at 12:23am
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uscra112 wrote on Sep 7th, 2022 at 5:35pm:
Throat erosion is a matter of chemistry, not temperature.  High nitroglycerine powders leave too much unused oxygen in the end gases, which reacts with the steel to form brittle micro-particles of iron oxide, which get washed away by the next shot.  Single base powders leave oxygen-poor end gases; the free nitrogen forms nitrides, and the mechanism continues as before.  According to the source from which I cribbed this information, modern double-base powders are more neutral, and so do not promote erosion nearly as much. 


bore scopes of throats ive seen in benchrest rifles shooting jacketed bullets at high pressure show severe "firecracking" (as they call it )with double based powders.Usually in just a few 1000 rounds.
is the data  you "cribbed" related to our lower pressure stuff?

  
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Cbashooter
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Re: ball powder for original pope
Reply #17 - Sep 8th, 2022 at 5:21pm
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uscra112 wrote on Sep 7th, 2022 at 5:35pm:
Throat erosion is a matter of chemistry, not temperature.  High nitroglycerine powders leave too much unused oxygen in the end gases, which reacts with the steel to form brittle micro-particles of iron oxide, which get washed away by the next shot.  Single base powders leave oxygen-poor end gases; the free nitrogen forms nitrides, and the mechanism continues as before.  According to the source from which I cribbed this information, modern double-base powders are more neutral, and so do not promote erosion nearly as much. 


this is the response from my shooting buddy who has a doctorate in chemistry. 

"Sorry, not true.  Both double base and single base powders are overall net reducing (i.e. "fuel rich").  This is what causes muzzle flash, when these leftover high temp fuel gases exit the muzzle and hit the air.  The source is correct to point out that nitroglycerine is more net oxidizing than is nitrocellulose, but double base powders are still net reducing overall"
« Last Edit: Sep 8th, 2022 at 6:51pm by Cbashooter »  
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uscra112
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Re: ball powder for original pope
Reply #18 - Sep 8th, 2022 at 8:13pm
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Not qualified to disagree with your friend directly, I'm only a superannuated dirty-fingernail mechanical engineer.

That crib goes back to 2014, and a scrap of text that I omitted suggests that it was a blog post.  Did not collect the name of the poster, but I assume it was somebody credible.  It made sense to me then, and still does.  Open to evidence to the contrary.  Can this be measured?  Has it been?
 
Being bored, I started trying to research this on the innertubes. There are a couple of highly technical research papers on the subject that I haven't managed to download (500+ pages tends to choke my slow satellite internet).  

About the only thing everybody seems to agree on is that lower temp/pressure erodes less, which is the world we cast bullet shooters live in.  

Another thing a lot of sources still say that bothers me greatly is that high nitroglycerine powders "burn hotter", which flies in the face of Boyle's Law, as I understand it.  

We know that some powders produce a magnificent muzzle flash, while others hardly any.    What are the implications?


« Last Edit: Sep 8th, 2022 at 8:21pm by uscra112 »  

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Cbashooter
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Re: ball powder for original pope
Reply #19 - Sep 8th, 2022 at 9:03pm
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I'm not smart enough to understand this complicated stuff.so I hang out with Guys who love guns and have Phd's.they have to dumb it down for me to understand and even then it's challenging for them.
  
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Re: ball powder for original pope
Reply #20 - Sep 14th, 2022 at 7:23pm
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Thanks uscra112, great information & nice to see some science at work!
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Re: ball powder for original pope
Reply #21 - Sep 14th, 2022 at 7:28pm
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Looks like the next step will be a peer reviewed scientific paper on the topic! There might even be a masters in this with thousands of hours required at the range gathering data... Wink Grin Grin 
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uscra112
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Re: ball powder for original pope
Reply #22 - Sep 14th, 2022 at 7:43pm
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What would answer the question once and for all would be an analysis of the end gases from the so-called "bomb" tests the powder makers are said to use.   I don't want to believe it's never been done, but have results ever been published?
  

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JLouis
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Re: ball powder for original pope
Reply #23 - Sep 14th, 2022 at 7:45pm
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Just being based on a self related experience I now have around 144,000 breach seated bullets down the barrel of my 32-40 Douglas barrel and having set a new ASSRA Record with it back in 2013 I finally retired that barrel.
And now and I can only guess that 99.8 % at a minimum was while using the various ball powders and nothing else.
The throat did indeed erode after time but by just simply breech seating the bullet further in did keep it shooting extremely competitive through out its useful life time. 
And it still will and I have also found the best way to keep track of how many bullets have gone down the bore is to just simply save all of your empty primer trays.
  

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