Powder Blending

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Powder Blending

Postby rob cullen » Fri May 08, 2020 8:58 pm

Newbie question and i have no intention of playing with fire , just curious
Is this just down by mixing 2 different powders based on their burn data to achieve a custom theoretical burn rate required for specific load or is it way more complex
Again just curious about the science side
Thanks
Rob
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Re: Powder Blending

Postby Hoot » Fri May 08, 2020 9:52 pm

You've just stepped into the JuJu zone!

It is generally not advised because a lot of internal ballistics is a function of what happens the instant the primer blows. The inability to control where the two powders settle out in a cartridge can lead to inconsistent powder ignition. IE a larger portion of the slower powder gets hit by the flame front first or vice versa. There's simply no way to control what happens inside the cartridge. This is especially exacerbated if the two powders weigh differently for the same amount by volume. Heavier settles toward the bottom and lighter floats on top of it. This places a high degree of importance as to how the rifle is oriented during and in between shots. The number of permutations are endless and as such ill advised. Go with the herd mentality. If 19 people say don't do it and 1 says there's nothing to worry about, I'll personally go with the 19 every time and I'm not a "fraidy cat". Ask my poor wife. ;)

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Re: Powder Blending

Postby rob cullen » Sat May 09, 2020 3:36 am

Thanks Hoot and yea i get my self in enough trouble experimenting with one type of powder at a time and the JUJU would kill this curious cat so i aint going there.
Main reason for question was that when i bought the SubSonic Hdys at gun shop i was quizzing the guy at shop about what powder he thought would be in the charge and he said it would be blended, i think i saw this advertised for Hdy superperformance cartridges in 308 as well a while back.
My way of thinking was pretty much as per your reply so how the hell would they control this balance in factory ammo?
Hopefully get everyones brains kicking into second gear as i haven't a clue how this would be controlled with some sort of stability and look forward to some answers
Cheers
Rob
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Re: Powder Blending

Postby MOOSE EARS » Sat May 09, 2020 5:49 am

Powder burn rates are controlled by the coatings and additives used during the formulation and manuf process. The size and shape of the flakes or kernels are a factor as well. Burn rate affects pressure in a certain case capacity combined with powder amount. Powders are never 'blended' and this should not be attempted, EVER! You have no way of knowing what the resulting burn rate and pressure would be. Bad idea!
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Re: Powder Blending

Postby rob cullen » Sat May 09, 2020 6:08 am

Thanks for the heads up Moose
So as you say powders are never blended which makes perfect sense from what you guys have said, why is it that they advertise it is blended ? Not having a crack at ya mate but just trying to get my head around this and understand it.Is this just advertising wank?
Cheers
Rob
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Re: Powder Blending

Postby MOOSE EARS » Sat May 09, 2020 6:24 pm

If you had access to Hornady's research and development lab, you could probably safely blend powders yourself. I have loaded for 40 yrs now and have seen a thing or two! You're dealing with controlled explosions running upwards of 65,000 psi with some cartridges. It's better to be safe than sorry. I push the limits myself sometimes and know what excess pressure can do, even with known parameters. And yes, Hornady's advertisement says blended powders and they may actually blend powders under controlled circumstances. But if you choose to play with blending your own powder, have real good insurance! Pressure spikes can occur and things change very quickly with some powders. W296 and H110 are great powders within established boundaries but can get nasty real quick, when limits are crossed. Same with A1680 and lots of others. Barrels and brass have their limits and once you push too hard on pressure to achieve higher velocity, you have a bomb next to your head. No load data has ever been published with blended powders. The results are just too unpredictable. Live long and prosper!
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Re: Powder Blending

Postby Hoot » Sat May 09, 2020 10:11 pm

FWIW, most commercial ammo is made with blended powders under as previously explained, laboratory conditions, with special pressure testing barrels. Most powders shipped in commercial ammo can not be purchased by consumers for reloading. The ammo manufacturers buy powders by the train car load based upon basic behavior. It gets "massaged" before being fit for ammo production. The stuff we get has to pass Litigation Attorney scrutiny. Even then, the same model powder will vary plus or minus a little, from one lot # to the next. Serious competition shooters who reload (not all do) buy large quantities of a single lot # when they find one that performs the way they want. Ditto on their brass, bullets and primers. For most, cost is not a concern. Us bottom feeders do as well as we can with what trickles down to our local reloading supplier. One of the most appealing aspects of the 450b is how forgiving it is of powder variations from one lot # to the next, Not nearly as fussy as 6 and 6.5mm competition calibers.

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Re: Powder Blending

Postby rob cullen » Mon May 11, 2020 4:55 am

Hi Moose / Hoot
Cheers for the info and that is more than a good enough explanation for me , way more info than i could find on good old google if you trust the author - you guys on this site i trust.
Partially dissapointed that i cant experiment and risk blowing my head off again but this ones a no brainer either way u go ( literally) from what you have said. I think i got only one cat life left out of 9 from all the dumb sh_t ive down in my life haha.
I will put to bed and never speak of this again.
Cheers for sharing your knowledge and experience, appreciated
Thanks
Rob
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Re: Powder Blending

Postby Hoot » Mon May 11, 2020 5:36 pm

rob cullen wrote:Hi Moose / Hoot
Cheers for the info and that is more than a good enough explanation for me , way more info than i could find on good old google if you trust the author - you guys on this site i trust.
Partially dissapointed that i cant experiment and risk blowing my head off again but this ones a no brainer either way u go ( literally) from what you have said. I think i got only one cat life left out of 9 from all the dumb sh_t ive down in my life haha.
I will put to bed and never speak of this again.
Cheers for sharing your knowledge and experience, appreciated
Thanks
Rob


At least you got one left. I used up #9 years ago and had to mooch a couple from less adventurous friends to make ends meet since then. ;)

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Re: Powder Blending

Postby rob cullen » Tue May 12, 2020 4:58 am

Haha Hoot
Thats Gold
Cheers
Rob
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