Powder coctail


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jeff-portnoy
September 26, 2012, 05:51 AM
Hi!
I have 7.62x25 cases and much Unicue powder! But I've read that Unicue - not the best choice for 7.62x25!
Please tell me - is it possible to make a powder coctail? Unicue + slower intensity powder?
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One more , ... Lee has trimming kit 7.62x25?

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1911Tuner
September 26, 2012, 06:10 AM
Mixing powders is generally a bad idea. I strongly advise against it.

jeff-portnoy
September 26, 2012, 06:16 AM
Mixing powders is generally a bad idea. I strongly advise against it.
why ?

Friendly, Don't Fire!
September 26, 2012, 06:17 AM
I agree with 1911Tuner.

Nothing is worth having a gun blow up, even if there is a remote chance of it happening, I would not do it! :uhoh:

I like my fingers, hands, face and body too much to take any chances like that. :eek:

If you ask why:
1. Are you a chemist?
2. Do you have an engineering degree in knowing everything about all the different powders that are made and which were made in the past?
3. Do you know positively the exact ingredients and how much of each is in each powder you intend to mix?

If you said NO to any of the three questions, there is your answer.

If you insist, it is your body, just make sure you don't injure or kill anyone else in the process of your playing with powders!

kingcheese
September 26, 2012, 06:25 AM
Its not considered a good idea because, you cannot entirely account for the characteristics of the powders together, and its not something that's recommended because you can buy another type of powder that would be good for that round

jwrowland77
September 26, 2012, 07:06 AM
Here's how you do it....take all the powder and dump it in a bowl together....and then dump all that powder in your garden or grass and water it in. Makes great fertilizer. It'll green it right up. It is highly dangerous to go mixing powders.

Walkalong
September 26, 2012, 07:24 AM
why ?You have no idea of the new burn rate.

So, in the words of Sheriff Buford T Justice, "You can think about it, but don't do it".

CMD-Ky
September 26, 2012, 07:24 AM
Reload as you choose, you may absolutely correct in your thoughts and actions. That being said, please don't offer your loads to others to shoot and please stand a distance from others when shooting.

cfullgraf
September 26, 2012, 08:34 AM
Hi!
I have 7.62x25 cases and much Unicue powder! But I've read that Unicue - not the best choice for 7.62x25!


What is the definition of "Unique - not the best choice for 7.62x25"?

Unique is very versatile. I use it in 380ACP to 45 Colt. Works well.

I cannot believe Unique by itself would not give adequate performance but I do not load 7.62x25 so I could be wrong.

To echo the sentiment of the others, mixing powders is a no-no for the home reloader.

bds
September 26, 2012, 08:35 AM
Mixing powders is generally a bad idea. I strongly advise against it.
why ?
Its not considered a good idea because, you cannot entirely account for the characteristics of the powders together
You have no idea of the new burn rate.
You got some good advise and I would follow them as most of us reloaders don't have access to chamber pressure testing equipment. Besides, if you are load developing for CZ52, you don't know what you don't know about YOUR CZ52 barrel.

Read Clark's posts on this thread - http://www.thehighroad.org/showthread.php?p=1438156#post1438156

http://www.thehighroad.org/attachment.php?s=&postid=249178

In 2005, John Bercovitz* and I bought 10 CZ52 barrels and tested them for hardness at JPL, where John Worked. Measurements between RC25 and RC35 were taken on intact 7.62x25mm barrels. A more modern 9mm CZ52 barrel tests at RC47. My 9mm CZ52 barrel steel might yield at 220ksi, while my 7.62x25mm Tokarev CZ52 barrel steel might yield at 120 ksi.

What does this mean to the non engineer?
The CZ52 is the only semi auto pistol I have ever tested that is weaker than the brass.
It does have the thinnest chamber, except for the Kel-Tec P3AT

Why does the CZ52 blow up in a work up, and no other pistol will, even the P3AT?
The P3AT is made of very strong steel.
The CZ52 is made sometimes mediocre steel, sometimes terrible steel.
The CZ52 cartridge has a larger diameter, causing more hoop stress for the same pressure.
The P3AT has poor case support, allowing only low pressure in a work up.
The CZ52 has good case support good enough to allow the primer pocket to be the limit of the brass, if the barrel did not split first.

Another forum thread discussing reloading 7.62x25 - http://forums.gunboards.com/showthread.php?21284-Back-to-reloading-7-62x25-for-the-CZ-52


This link has a compilation of 7.62x25 loads with Unique - http://www.makarov.com/tokloaddata.html

Note: Always verify "internet/online forum load data" with published load data and conduct your own powder work up from start charge.

Taking Clark's posts into consideration, I suggest you stay with start/lower end of published load data.

Enjoy your loads with Unique and don't ever mix powders, EVER! :D

Be safe and keep us posted with a range report!

srtolly
September 26, 2012, 12:16 PM
I can't believe you can't find load data for 7.62x25 using Unique. I have to agree that mixing powders is a bad idea. A lot of good info here.

zxcvbob
September 26, 2012, 12:35 PM
Unique should be adequate, and you should be able to find load data for it. Power Pistol or AA#7 is probably what you want for that cartridge. (Where did you find reloadable brass?)

Don't be mixing powders unless you are an expert at it -- I doubt there are *any* experts on this site, and certainly not you or me. Most reloaders don't even like to mix different lot numbers of the same powder.

homatok
September 26, 2012, 03:28 PM
Can you mix powders??---Absolutely!!!

Should you mix powders???---ABSOLUTELY NOT!!!! (FOR ALL THE REASONS STATED ABOVE)

Lost Sheep
September 26, 2012, 05:02 PM
People used to do it. It was quite common to introduce a bit of faster powder into the case containing a slow, hard-to-ignite powder in order to get consistent ignition.

Nowadays, we have better primers and better powders.

From what I understand there are several problems in getting consistent pressure/time curves. (Essential to avoid pressure spikes that tend to destroy firearms and injure or kill those nearby.)

Mixing of the powders. Sometimes you want the fast powder near the primer and the slower powder further up. But it is hard to keep the two from migrating into one another.

Unmixing of the powders. Sometimes you may want to have the two powders mixed uniformly. But the nature of powders is that larger granules will tend to separate from smaller granules.

If you mix the two powders before loading, you don't know how much of each powder is going into your weighed powder charge. Very difficult to control the proportions.
If you mix by adding a specific amount of each powder into individual cases, you know the proportions, but still don't control the mixing inside the case.

You can prevent mixing inside the case if you separate the powders with a wad, but then you introduce the additional effect of an extra component and its unknown effect on the pressure-time curve.

You can limit the mixing effects by using a 100% or compressed load.

So, it can be done safely. Professionals used to do it all the time. But they ALWAYS had laboratories, pressure test barrels, protective barriers, lots of time and money.

THIS SHOULD NEVER BE DONE WITHOUT A BALLISTICS LAB!

What you are contemplating is just short of brewing your own propellant on your kitchen stove.

In a word. Insane.

A reasonable question, yes. But insane to contemplate doing.

Respectfully

Lost Sheep

CZ57
September 26, 2012, 06:31 PM
Ramshot used to list data for the 7.62 X 25mm. Currently they don't but you should be able to contact them with the 800 number given at their website. BTW, Ramshot and Accurate Arms use the same ballistician. Last time I checked, Accurate still listed data for the 7.62 X 25mm. Check out their website. ;)

Ehtereon11B
September 26, 2012, 11:59 PM
The main reason why it is a bad idea to mix powders is because it is hard enough to predict a burn rate using a single powder type. Mixing 2 powders is literally a recipe for disaster. It is possible to molecular bind powders together that a few companies have done to some advanced proprietary powders. Such as LR powder or Superformance. Long story short without getting into chemistry, don't do it. Your weapons and safety will thank you.

ljnowell
September 27, 2012, 01:20 AM
Im very proud of this forum right now. This is something that almost all of us contemplated when we first started researching reloading. Too many times people get berated or called stupid for thinking about it. None of that here, just education. +1 guys.

jeff-portnoy
September 27, 2012, 04:33 AM
People used to do it. It was quite common to introduce a bit of faster powder into the case containing a slow, hard-to-ignite powder in order to get consistent ignition.

Nowadays, we have better primers and better powders.

From what I understand there are several problems in getting consistent pressure/time curves. (Essential to avoid pressure spikes that tend to destroy firearms and injure or kill those nearby.)

Mixing of the powders. Sometimes you want the fast powder near the primer and the slower powder further up. But it is hard to keep the two from migrating into one another.

Unmixing of the powders. Sometimes you may want to have the two powders mixed uniformly. But the nature of powders is that larger granules will tend to separate from smaller granules.

If you mix the two powders before loading, you don't know how much of each powder is going into your weighed powder charge. Very difficult to control the proportions.
If you mix by adding a specific amount of each powder into individual cases, you know the proportions, but still don't control the mixing inside the case.

You can prevent mixing inside the case if you separate the powders with a wad, but then you introduce the additional effect of an extra component and its unknown effect on the pressure-time curve.

You can limit the mixing effects by using a 100% or compressed load.

So, it can be done safely. Professionals used to do it all the time. But they ALWAYS had laboratories, pressure test barrels, protective barriers, lots of time and money.

THIS SHOULD NEVER BE DONE WITHOUT A BALLISTICS LAB!

What you are contemplating is just short of brewing your own propellant on your kitchen stove.

In a word. Insane.

A reasonable question, yes. But insane to contemplate doing.

Respectfully

Lost Sheep
Thanks for complete answer

jeff-portnoy
September 27, 2012, 04:40 AM
(Where did you find reloadable brass?)

this is not a problem - http://www.grafs.com/retail/catalog/product/productId/17868

1911Tuner
September 27, 2012, 05:53 AM
In a rush and had to do a hit and run yesterday...

All good information by Lost Sheep. Two points that haven't been addressed is that by using a small charge of a quick powder like Bullseye to help ignite a slow powder like H110 or Olin 296 is that it changes the burn characteristics of the slow powder...and it may not burn so slowly any more.

The other is that the priming charge takes up space in the case, and unless you do a volume-to-volume conversion, you won't know how much of the slower powder to use to maintain a consistent volume. You can drive pressures up significantly by simply adding an inert filler on top of the powder charge and reducing case volume. Reducing the volume in the case drives pressures up. As pressures increase, the powder burns quicker. The quicker the power burns, the more rapidly the pressure increases, etc etc.

kingcheese
September 27, 2012, 06:59 AM
In my lyman replacing book it adresses that issue, the proper way to go about it is to look at published data and go for the fastest burning powder that you can safely come closest to filling the case with, and the book list its charts so that the first load with a given projectile is the best for meeting those requirements

Walkalong
September 27, 2012, 07:27 AM
I did an experiment with some leftover AA #5 and HS-6. I mixed equal amounts very thoroughly and loaded some 9MM and .45 ACP with it. I used AA #5 data since it was the faster of the two. I started low, thankfully. The velocities I got were quite a bit faster than they should have been assuming the burn rates of the two powders was not affected. This was only a small test with two powders, but it was enough to show me that burn rates do not necessarily remain the same when powders are mixed.

So, I'll quote 1911tuner again.
Mixing powders is generally a bad idea. I strongly advise against it.


I used the rest for fertilizer. :)

homatok
September 27, 2012, 03:51 PM
Posted by Lost Sheep:
"People used to do it. It was quite common to introduce a bit of faster powder into the case containing a slow, hard-to-ignite powder in order to get consistent ignition."

The process was/is called duplex(ing) loads and is very different from what I thought the OP was asking. As pointed out, duplexing involves placing a measured amount of a fast powder over the primer and then carefully adding the slower powder on top. The powders are not allowed to mix! Sucess, as also pointed out, requires the case to be filled with (slightly compressed) powder(s) or the use of filler to accomplish the same thing.

Lost Sheep
September 27, 2012, 09:56 PM
Imagine what it was like using Cordite and count our blessings.

Lost Sheep

wtr100
September 27, 2012, 10:10 PM
I think the mixing was called a booster charge and was done with cases that were filled nearly to the top with powder

iiranger
September 28, 2012, 04:16 PM
Mixing powder is exactly what the factories do. That is how they achieve "canister burn rate." Then there are coatings that also effect burn rate. Col Nonte, in one of his books, describes the process. When the machine is turned on, they have no exact idea what the powder that comes out will be. Sure, they know if it will be stick or ball or flake or ??? but they hold back lots that are near the burn rate they sell as "XXX" powder and blend them to be within acceptability. This is why you will hear all the complaining that the new can or powder just isn't the same as the old, empty can and the sale of 8 lbers.

You? If you go to the Hodgdon web site they can give you more data for any cartridge than you will use in a lifetime. With the shoulder, I am guessing that 7.62x25 might want a trifle slower powder for hottest velocity but no reason you cannot use a reduced load for acceptable performance.

As said, without a ballistics lab to regulate your results (and the safety equipment) DON'T unless you are tired of living. Luck. Happy Trails.

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