MIXING Powders...


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msjayhawk
April 25, 2013, 12:01 AM
I have an experiment I have to do for work (Really!) and I have been switching from Green Dot and 4100 powder. I have blown up a few barrels with Green Dot, and have not quite gotten what I need with 4100 and ZERO barrel growth. My little canon system is killing me. I thought I could get it in five or six shots and am now on eleven.

My question is, if I mix 4100 and Green Dot, will I end up with about an AA#5 or Closer to AA#2?

Don't worry, this is all being done from a bunker, remotely, for a potential military system. I am an explosive expert, and this powder stuff is confusing me! I am starting to see why it took two years to develop the .327 magnum..

Appreciate the help.

PS- The reason I am thinking of mixing them is that all of the powder I want is sold out now. People list it as available, but the second you order it they will tell you it will be ten weeks...

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Certaindeaf
April 25, 2013, 12:09 AM
I'd PM Clark. He can blow anything up.

GLOOB
April 25, 2013, 12:09 AM
I would try duplex loading before mixing. You said you maxed out on a caseful of 4100 with no kaplooey? So load a grain of Green Dot, first. Then top off with enough 4100 to prevent any powder movement.

If that doesn't blow things up, go up from there.

TexasShooter59
April 25, 2013, 12:11 AM
Thinking back to when I was in engineering, have you tried calling the companies who have the powder you want (like Hodgdon, IMR, Alliant, etc.) and asking them for some samples you can test with? I'm assuming with military contracts, if you hit something big, it could mean purchases of quite a bit of powder and money for them. Therefore, it might be worth their while to provide some to you. It is at least worth a few phone calls to find out.

Mobuck
April 25, 2013, 12:13 AM
Try something like Red Dot or TiteGroup. If a case full of those don't blow it up, you need a bigger case or a heavier projectile.

bds
April 25, 2013, 12:14 AM
Might help if we sort of have a better idea of what the final objective is ... ;)

There may be some chemistry type THR members who may read this thread - I am limited by first year chemistry/physics I took in college.

Depending on what burn rate powders you may need, some THR members close to you may provide you with some for testing/research. ;)



BTW, we do have a "Pay it Forward (http://www.thehighroad.org/showthread.php?t=698208&page=25)" thread ... Never hurts to ask ... "Ask and you shall receive".

State your need and some may just pay forward you some powder. :D

GLOOB
April 25, 2013, 12:17 AM
Mobuck and BDS, lol.

Objective is already stated. He needs more velocity than 4100 is giving, and less blowing-up-of-the-barrel than the Green Dot is providing. :rolleyes:

msjayhawk
April 25, 2013, 12:20 AM
All, really, with this ammo rush and all, people don't have the stuff. Like I said they will list having it, but you call and 'no dice'.

Can't really say the final objective yet, can later. It is an armed forces supplement hopefully....

bds
April 25, 2013, 12:33 AM
Objective is already stated. He needs more velocity than 4100 is giving, and less blowing-up-of-the-barrel than the Green Dot is providing
OK. I was scratching my head when I saw the jump from Green Dot to 4100. :confused:

msjayhawk, have you considered the use of retardants if you want slower burn rate than Green Dot?

I really think having different burn rate powders is the way to go though instead of mixing different powders. I mean, in the end, you'll have to produce results that are reproducable. How will you do that if your powder mix is not reproducable or you run out of the mixed powder?

msjayhawk
April 25, 2013, 12:40 AM
BDS. What are retardants I could use? I am really stuck on a fast timeline and have Green Dot, 4100, 4350, and Mag Pro.. I am about 20 years into this, but not with powders, more with compositions... www.demex.us

KansasSasquatch
April 25, 2013, 12:43 AM
Powder Valley http://www.powdervalleyinc.com/ has IMR 4756 listed in stock in 1lb jugs. It's 2 steps faster on this http://www.imrpowder.com/burn-rate.html burn rate chart than AA#5. They also have IMR 7625 in stock in 1lb and 8lb jugs which is only 2 steps slower than AA#2. Also IMR PB which is 2 steps faster than AA#2. And Winchest WSH, 5 steps faster than AA#2. They have options available, it's just going to be 5 weeks before you'd get it. If you were close I have plenty of powders I'd give you in the burn rate range that you want. Natchezss.com has HP-38 and Win 231 in stock, I hear their shipping has been a little quicker than PV.

kwg020
April 25, 2013, 12:44 AM
Typically you get more velocity out of longer barrels and slower powders. How long is your barrel? How heavy is the projectile and what is the caliber? Green dot and 4100 are at opposite ends of the pistol powder chart. It's been said, if you want to blow something up just fill it full of Red Dot. It's at the fast end of the powder chart. Use this link and ask these guys. kwg

http://24hourcampfire.com/ubbthreads/ubbthreads.php/forums/67/1/Reloading_Software

bds
April 25, 2013, 12:46 AM
I am assuming you know A LOT more than I do but to cover the basics here goes.

Smokeless powder burns (like a match head compound mixture) and does not explode.

If you look at the powder burn rate chart (http://www.hodgdon.com/burn-rate.html), you'll see that Green Dot is a very fast burning powder compared to 4100.

You could get a incremental samples of various burn rate powder in between Green Dot and 4100 to see what burn rate powder will get to closer to what you are trying to achieve.

When you get in the "ball park" you can fine tune the powder selection by narrowing your choices.

I hope I didn't just post what you already knew. :uhoh:

But if we can identify the narrow range of burn rate powders you need, it would be a simple matter of obtaining them (either by purchase from THR members near you or donation to testing/research).

Certaindeaf
April 25, 2013, 12:46 AM
I'd honestly talk to Clark and have a little patience.

msjayhawk
April 25, 2013, 12:47 AM
KansasSasquatch! I appreciated it, but I have to shoot tomorrow. I appreciate you helping a ME from KU...

bds
April 25, 2013, 01:00 AM
How about this?

Do you need something that burns like AA#2, #5 or #7?

hovercat
April 25, 2013, 01:15 AM
No mixing. Some powders are nitrocellulose based. Some nitroglycerine based. Some both.
Different additives and coatings. Powder is an engineered product, but even the Mfg has to test each lot to make sure it is in specs.

KansasSasquatch
April 25, 2013, 02:54 AM
He needs something in the "hard to find" range, between #2 and #5. Unique, Trail Boss, W231, Power Pistol, True Blue, etc., going by what he wrote earlier. I could help him with any of those but Power Pistol but he's too far away.

Kinda hard to suggest anything without knowing exactly what his parameters are but he probably can't tell us due to confidentiality requirements.

GLOOB
April 25, 2013, 03:02 AM
.... or go over to CastBoolits.com and get real answers.

bds
April 25, 2013, 03:31 AM
While posting for another thread (http://www.thehighroad.org/showthread.php?p=8891569#post8891569), I found this pdf (http://ota.fas.org/reports/8017.pdf) to be perhaps pertinent to this thread on mixing or "blending" powders. I still say OP is better off using a group of particular burn rate powders than mixing two different powders.
The basic process for the manufacture of gunpowders involves the following steps:

- mixture of ingredients, which may include the raw ingredients as well as surplus and reworked powders;
- granulation, where the “dough” is extruded, chopped, or otherwise granulated to form the various grains;
- screening of grains into designated sizes; and
- blending of various batches to get the desired ballistic characteristics.

In the smokeless powder manufacturing process, nitroglycerine, nitrocellulose, and other additives are combined to make various grades before the blending process. Smokeless powder grades therefore differ due to size differences and composition differences (various amounts of nitroglycerine)...

In a given grade of powder, variations in density and other fluctuations during the manufacturing process can cause considerable variations in the ballistic properties of the final powder. As the handIoader generally has no means of controlling his ballistics other than the weight or volume of powder added, the ballistic properties of a particular grade of powder must be carefully controlled by blending. A given brand name product may therefore contain parts of several batches, blended like brandy to give the desired ballistic properties. Several sequential blending operations may be necessary before the product meets the required specifications. If the ballistic properties of a particular batch or blended lot are too far off, the material must be reprocessed or used for something other than hand loading.

Walkalong
April 25, 2013, 08:21 AM
There is no way for us to calculate the new "burn rate" of mixed powders.

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