When mixing powders (I'm mixing 31 g of Somchem 335 and 31g of Somchem 365 in a 375 h&h behind a 380g bullet) is there any advantage/disadvantage to mixing the powders or should one stack one on top of the other and if so which one? Probably been asked a hudnred times but anyway.....

Berger....hard to tell if you are serious or not or if you are just lonely and want someone to talk to.....NEVER...NEVER....NEVER....mix powders.

There are a lot of reasons you should not do this but let me give you the simpliest one. You can never duplicate the mix.....so your results will never be the same but never mind that....it's just plain dangeous.

God I hope you are just kidding!

DB Bill,

Shhhhh...don't tell Berger that! He is a scientist from South Africa...thye have their own way of doing things there...

Actually guys, I'm following the recomended load of the manufacturer of the bullet and the official tester. You can pick up the test results in Magnum magazine and you'll find they recommended 31.5g S335 and 31.5g S365 as an optimal load for the 380g Rhino.

Scientist or not. Sounds like BOOM....BIG BOOM... to me. Just hope no fingers are lost.

Deaddog, DBbull,ricciardelli, I was looking for serious posts, not "I don't know what I'm talking about but think its bad posts". Thanks but no thanks for the sarcasm. Now to my original question. When mixing two powders (which the experts recomend) do you mix or stack and if stack, which one first.

Berger,
I would think that there would be mixing over time of the two powders if they were stacked and jostled about in the field.

With a compressed load it is less likely, but if it is not compressed, the load should be mixed to attempt to get uniformity.

Then if you shook it enough to get thorough mixing you may have powdered some granules, increased the speed of ignition and raised the pressure, possibly.

Since you have the option of "shaking" I guess it is not a compressed load.

Sounds like a crap shoot for accuracy any way you do it. I wouldn't like having to mix powders for many reasons: safety, variable internal ballistics, etc.

What does your source for this load say about it?

Which do you load first, the faster or slower powder if stacked?

Too bad you don't have the correct single powder.

Berger,

By the way, who is the manufacturer?

American reloading authors and publishers are a lawsuit shy bunch of nice guys that don't want to help put fragments of expensive gun deep under their readers' skin. As a result, every piece of gun-related reading material most of us can lay our hands on starts out with some discussion of safety (how many times do you read the phrase, "first, make sure the gun is unloaded"?), and duplex loads are on the safety list. I think they don't want reloaders getting "creative", because some of the obvious creative duplex loads (e. g. mixing a very fast with a very slow powder in an attempt to get an early rise to peak presure when the fast powder burns and a long period of sustained high pressure as the slow powder burns) are a probably a fantastically bad idea. Rather than give someone guidelines on how to do a hazardous job safely, it is more convenient and possibly more prudent to tell them not to even think about doing it.

H. C.

Thanks henryc470,

That explains the initial replies to my enquiry! Anyway, I have had very good results with the S336/365 combo. I had nothing but pressure problems with any of the single loads recomended by the manufacturer of the bullet. I think the bullet length had something to do with it. without the mix, I could not get good results without dropping below 200fps. Anyway, lawsuits aside, what do you think? will it make any difference if I mix the powder (literally shake the brass prior to loading the bullet) or just load with one in front of the other?

Thanks in advance,

Whoops, make that 2000fps in the last post!

Berger, it seems to me the reason for combining the powders is to get a burning rate unachievable without mixing the two. So I would guess you would want to mix them as throughly as possible. Otherwise if they were just stacked I would think your variations in ignition, pressure etc., would be extreme. That said just remember when it comes to combustible chemistry I'm the guy that's depriving some village of a good idiot by not being there

I must say, my thoughts exactly. that's why i've been doing the shake after dropping the powder in. But now I'm committed to finding out and I've loaded it three ways and will tell all after next weekend given that as, those predict above, I do not blow my hand off or am befallen by the explosion of my bolt or some other mishap that I very much doubt will happen. My real guess? Not much will change either way do to the landrover effect (inadvertant mixing) or little or no difference in the burn rate of the powders I'm using (335/365 not being that different), but I'll let you know...

Berger....that's DBBill if you please not DBBull!

I'm going to predict not much difference in the three different loadings. Since the case is not full, I think the primer is going to do a pretty good job of stirring things up before a whole lot of powder burning takes place.

P. S. Which bullet manufacturer?

H. C.

[ 07-01-2002, 02:06: Message edited by: HenryC470 ]

Hey Berger,

I want to say "stop", but since you really want to go at it, be careful then.
Keep us posted of what you find out. It might open up something new.
Does mixing powder really endanger safety? Well if you put one grain of each
powder type into that echo-rebounding empty 375H&H case, does this
endanger anything? So the tricky part is "how not to put too much powder in
it", I suggest starting with the minimum load(or slightly below it) of the slower
burning powder, then add the faster burning powder, grain by grain,
meanwhile monitoring pressure. (If I were you I would not start the
experiment until I have a electronic pressure gauge installed on my rifle and a
long long string attached to the trigger, but I am not you.)

Given one caliber only, you'll have "powder combinations" "maximum powder
charge", "mix ratio", "mix method", "bullet weight" and "barrel length". You
got at least 6 relevant variables to experiment on, it's worth a lifetime of
research.

When you have mastered the two-powder scenario, then you move on to
three-powder land. That could be set to be one's "purpose of the next life."

If you find my suggestions mixed with a slight amount of sarcasm....you are
the one who gave me the idea.

Berger,

I would mix the powder for what you are trying to achieve.

Also, it should not matter much if the mixing alters because of vibration. Basically all the powder sets fire at once and the burning rate is controlled by each granule of powder as opposed to the powder gradually setting fire throughout its bulk. You simply have two different burning rate granules in the case.

The main thing you need to do is make sure that each cartrdige has the same amount of each powder.

Mike

Berger - I can hardly believe your post either, but obviously you are quite serious so I will reply in kind.

Open any bag of potato chips and examine it and you will find the answer to mixing powders. The smaller particles are always going to somehow shift towards the bottom.

The trouble with ammunition is "What's the bottom?" Depends on how they are stacked or manipulated. But the point is the smaller stuff is going one way and the larger particles are going the other.

Compressing the load SHOULD minimize this one would think, but if this proceedure is what your powder manufacturer recommends, I suggest you write and ask them.

Mixing powders is perhaps the first commandment of reloading: Thou shalt NOT mix thy powders.

I tried it ONCE and took the duplex loaded ammo to the range along with my chronograph. The velocity and pressure results were all over the place. This led me to conclude my idea wasn't so smart.

Now, for what it's worth, let me tell you I was using a fast pistol powder in the bottom of a case and held there (theoretically) by a wad of kleenex and on top of that a VERY slow burning stick powder. In other words, very dissimilar powders. I am guessing YOUR two powders are at least similar??? If so, the potential for serious results may be lessened.

Still, Berger, it all sounds like a long around way to reach the same point I believe you could do with a SINGLE powder. But I wish you luck in your indeavor!

I would definitely mix them. This is my theory on stacking: If the charge (extreme example of Bullseye and RE-25) is compressed and you stacked a fast on top of slow that the fast stuff would cause a pressure spike since it's getting hit first and trying to burn in a case with no airspace. This would be compounded by the fact that both powders will burn faster as the pressure goes too high. I imagine if the fast was stacked on slow it wouldn�t be as bad, but I still think it would be close to the same dangerous result.

If they are mixed and the same mfg and type (ball, cyl, flake, etc), and close in burn rate I don�t what the big deal is. I would imagine the greater the difference in burn rate the more the faster one would act like a primer that's too hot and cause the slower one to burn faster than expected. So I would expect to see the end result powder that is a little faster than the average of the two.

I was going to experiment by mixing Alliant �Blue Dot� with �2400� for my shotgun, but they recently came out with �Steel� which is the burn rate I was after. I�m so glad because I wasn�t looking forward to another variable to reloading.

I know what it�s like to get the non-answers you�ve been getting. I�ve been looking for years on data of what certain guns can take before they blow. You know the gun mfg knows the answer but they�ll never tell. Right now I�m working on a slug load for the new 3-1/2� 12ga. There is no data available and when I search for any info/ideas to help, 99% say �Don�t experiment!�, �Only load per the book!�, etc etc, just like everyone is telling you. So I hope I helped with your question somewhat.. And good luck!

chevota,

If the two powers are in the case together what should happen is:

Pressure should build at a rate that is slower than the quicker powder but faster than the slower powder.

In other words, let us say that we had 35 grains of 4064 and 35 grains of 4350, then our "loading data" would be similar to some powder that had a burn rate somewhere between 4064 and 4350.

How the powder is mixed (assuming the load is not compressed)should not make too much difference as it is each granule that controls the burn rate.

If I was doing this myself I would charge all the cases with Powder A and then add Powder B and just let the powders do whatever they will do.

Mike

Berger - You've gotten a lot of comments here. Most of it, including my own, were generally negative towards what you want to do.

However, of all the respondents, I believe I am the only one who has actually experimented with duplex loads. My results were really frightening.

However, I was using two very dissimilar powders. You state that your two powders are SIMILAR.

Because of this, most likely you will come home from your testing still in one piece and your gun as well.

My first question to you when you get back will be "What have you accomplished?"

As I said earlier, I think you are going a very circular route to reach your destination. I maintain that your can accomplish what you need for your gun with a SINGLE powder.

And I suggest that unless you actuall chronograph your duplex loads and get some idea of their consistency......you won't know much more than you did when you started this quest.
For sure this new duplex load is going to go bang about like all your other loads but that doesn't mean you have accomplished anything.

They've got to PROVE their consistency and the load's accuracy. Then if this is a hunting load you are working on, I suppose you need to put some of these shells in your landrover and let them bounce around for a couple of weeks to allow the powder to go wherever it wants and then fully test it again!

So, I think you've got a lot of work ahead of you to accomplish anything of any value.

Again, good luck. Please do report back.

p45

Thanks everyone for the various answers, and maybe I did not explain the background thouroughly behind the duplex loads proposed (which I have already fired by the way). Last year Rhino came out with a new 380g bullet for the 375h&h. In its review, debu article in Magnum magazine they gave the background to the bullet, how they eventually prevented tipping on entry and how they constructed a bullet design that would fly straight and mushroom effectively. Most results indicated they could get the bullet to fly at around 2100fps give or take. Obviously I was very excited about this bullet. If it would work, it brings the 375 into a range of a true dangerous game rifle approaching the 416 Rigby in stopping power and bullet weight. As I use my rifle for hunting occassionally, but mostly for a carry rifle in dangerous game country while on survey, I wanted to try this new bullet out and see if it would replace the traditional Barnes X at 300g. The tester recomended three potential loads in Magnum, two singles and a duplex (I believe Somchem 365, S341 and then the duplex of S335/365 I described), all of which achieved the low 2100 velocities. In my Ruger Safari Express I first eagerly loaded the two singles three grains below the lowest loads recomended in the article. While the bullet flew accuratly, my velocity was way low (chronographed at below 2000 fps in all cases), and I was clearly experiencing pressure problems. The bolt was feeling sticky and I even had the bolt jam a couple of times. I went back to the drawing table, spoke to the manufacturer, tried a couple of other single powder charges recomended and still had the same pressure signs. Only after about five trips to the range and maybe fifty bullets through the barrel none achieving good results did I try the duplex load of 31g S335/ 31g S365 which was 1 grain in total below what was recomended by the tester. At the range voila! Chronographed velocities of 2350!, consistantly, no pressure problems and twenty rounds through the barrel later I was a happy man. this means that the bullet is a real knockdown king if I can keep it performing like this, and now it is just to see how the bullet performs on something big and tough with lots of bone, like an eland before I rely on it. Thus came my stacking question as I achieved the above results by shaking the cartridge after putting the powder in and before seating the bullet and thus the question was serious. I will try the various combos (335 in front, 365 in front and mixed) and will report back. My suspicion is that there will be no real difference but who knows.

I strongly suspect that some lots of powders ARE blends of similar powders, done at the factory.

While I don't intend to experiment with any duplex loads, I can readily believe that a "homemade" blend of two canister lots of similar powders, each with similar granule size, would result in a propellant which performs consistently.

I have a harder time believing, however, that the kind of ballistic improvement that Berger cites can be achieved with a duplex load unless all powders available are either somewhat too quick or somewhat too slow for a given cartridge/bullet combination. If the blended powder yielded a burning rate that was better suited to the cartridge, then it is possible. I think the same improvement would result from using a single powder of the proper burning rate, however.

After all, the total energy content of a given amount of nitrocellulose (or
nitrocellulose/nitroglycerine) is the same, no matter how the burning rate is manipulated.

Stonecreek, I would go even farther, and postulate that nearly ALL powders are a blend.

It's easy for us spoiled U.S. consumers to say don't do it, with over 100 powders to choose from. A guy in South Africa, I believe, gets a choice of six?

I wonder how creative this group would get if we only had six powders? Just wondering. Dutch.

Berger - Interesting update and amazing results. I think you are in uncharted waters here and don't know anyone who can really help you. What little I had experimented with duplex loads was certainly no help.

I am thinking that somewhere I heard Hogdon's powders, at least some of them, were blends? But I wouldn't swear to that as fact. Perhaps it was that he "blended" different lots of the SAME powder. I don't recall.

Anyway, congrats on your amazing results. As I said, you might need to load some shells like this now and do the "landrover test" of letting them bounce around in your vehicle for a couple of weeks and then re-test. If they still perform as before I would forget it and start using them.
You may have found a workable combination.

Berger -- You mention "Magnum Magazine". If you possibly could I would appreciate you posting the information about how to subscribe to the magazine or E-Mail me the information. I have been trying to find this magazine for some time, and have been unsuccessful. Thanks in advance and good shooting.

[ 07-02-2002, 01:58: Message edited by: phurley ]

Whoops, double.

[ 07-02-2002, 04:21: Message edited by: Cold Bore ]

Mr. Berger:

I'm sure you're a smart guy.

I'm sure you know what you're doing.

I'm sure you've gotten away with your experiments.

=====

I would still tell you to cease and desist on future duplex loading.

There. I told you. I feel better now. I did what I could.

Russ

Stonecreek, Dutch, you are right. It has been 35 years or so but as I remember powders are made in large volume, ball powders in mixing tanks that hold thousands of gallons, single base in not so large a volume but in a steady production line 24/7. When the powder is finished it is sampled and tested for burning rate in what is called a closed bomb test. To achieve the desired burn rate different lots are blended and coated with retardants. The ball we produced for the army was screened and sorted by diameter as that had an effect on burn rate also. To make a lot of 4320 is not just as simple as throwing the ingredients in a pot and stirring. So many chemicals and processes are necessary to convert cellulose into gun powder that little variations creep into the process which require blending of burn rates to get a match to the required burn rate for any given cannister powder of for the powder that is being loaded into military ammo. As I said it has been 35 years and I was working on a WW11 era facility so my memory of all the details is a little fuzzy and I'm sure some of the processes have changed. But blending by the manufacturers is a reality whether they will admit it or not. And duplex loading has been played around with for many years. It can be done. This in no way should be construed as an endorsement of duplex loading. Responsible adults make their own decisions based on the facts. By the way, being in the presence of fifty gallons of nitroglycerin is an experience everyone should have. Now thats fun stuff.

I would call the powder manufacturer and see what they had to say about shaken or stacked?

Do you run with scissors too?

One thing to think about. If the powder is stacked, the fast burning powder next to the primer could cause excessive pressure and blow. If the slower powder is next to the primer then it would not be such a problem. By the time the slower powder ignites and pushes the bullet down the barrel the faster powder is lit and causes hire pressure. In theory, this might be the case. With powder mixed you won't have to worry about it. I don't think you will have to really worry about it, by the time you load and go to the range the vibration will mix the powders. Just something to think about. This is the only logical idea I can think of for mixing powders.

I understand not having access to powder. Just becareful.

Thanks all,

As I've said, I am following at least one testers recomendation and have had good results. I must say I am not keen about pre-mixing large amounts of powder and then going about loading. There, I would suspect, the landrover effect (as it has been reffered to here) would almost certainly come into effect as the slightly smaller grains fall to the bottom. I am very happy carefully measuring each little load by hand. also, since either of the loads I am using, if they were doubled, would not exceed the recomended grains for the straight load, I think its pretty safe.
One of my freinds has also just enquired as to whether my "pressure" problems (bolt sticking) I described might not have been using the relatively thick walled PMP cases, which were expanding due to the added resistance of pushing this long bullet out and maybe I should try and find some Winchester (thin walled) cases. Any thoughts on that?

Also for Phurley

MAGNUM MAGAZINE
P O BOX 35204
NORTHWAY 4065
DURBAN
Telephone 031 - 5726551
Fax 031- 5628389
e-mail manmagnum@saol.com

Berger,
As I understand it S335 is pretty fast with a burn rate similar to IMR 3031, and S365 is similar to IMR 4350, a medium or medium-slow powder.

It sure seems to me that S365 would be the better powder for a 380 grain bullet.

Have you tried a drop tubed and compressed load of S365 if you have no pressure signs and low velocities with the full case of S365 so far?

380 grain 375 caliber reloading data is scarce indeed. Too bad you can't get hold of some RL 15 powder.

FWIW, here is some data from the first edition of the Barnes reloading manual for their original 350 grain bullet (RNSP) in a 26" barrel, 375 H&H, max loads:

IMR 4320 65.5 grn 2405 fps
IMR 4064 62.0 grn 2324 fps
H 414 75.0 grn 2415 fps
H 380 66.0 grn 2356 fps
RL 15 66.5 grn 2407 fps
AA 2700 66.0 grn 2301 fps

And here is some data from the Hodgdon Data Manual N0. 26, 350 grain bullet, 26" barrel, 375 H&H, max loads (they must have had one of those fast barreled rifles):

H4831 76.0 grn 2452 fps
H4350 72.0 grn 2432 fps
H414 71.0 grn 2461 fps
H380 67.0 grn 2414 fps

If you are getting 2380 fps with the 380 grain bullet in a 26" barrel, this suggests that you may be operating at max pressure or a bit on the hot side.

I pesonally would not want to deal with the variability potential of duplex loads.

I would get all I could out of the S365 load and let it go at that, until I could find some new powders to try.

I think the above loads are a place to hang your hat for powder selection if you have the chance. Since your bullets are 380 grains instead of the 350's, starting 15% below the above max loads might be a good starting point to work up from.

And now from the Twilight Zone, the old P.O. Ackley load for his ".375 Magnum Improved Ackley"
with a 350 grain bullet, no barrel length specified:

IMR 4831 88.0 grn 2650 fps ... (Twilight Zone theme music playing in background) ...

How about rechambering to 375 Weatherby? That might get you another 100 fps with your S365 and no duplexing. Maybe no drop tube nor heavy compression would be needed then.

Berger
Wouldn't it be better to mix the powder first before putting it in the case? ie measure your powder,bit of this bit of that,into a pan, mix it THEN load it in the case. I reckon buy loading the case then shaking it you would not be getting an even mix as the air space above the powder would not be big enough to allow the powder to turn over. If this happens what is the point of shaking in the first place? you may as well stack it.
Just my 2 bobs worth

Bakes

Folks,

What Berger is trying to do here, is to overcome our VERY limited range of powders. It has indeed been written that duplex loads are the answer to 'fill the gaps' between S265, S335, S341, S365 and S385. Would you believe, those are the only rifle propellants available to us. And let me tell you, those gaps are big enough to turn a pantechnicon around in.

Personally, I would want to learn a LOT more about duplex loads before messing with them. I would think that a 380gr Rhino (solid shank, bonded-core, � l� TBBC or Swift) at anything above 2100fps just has to be very bad news for anything standing in its way, but Berger is clearly looking to hedge his bets, here. I see nothing wrong with that, as long as he goes very carefully where angels fear to tread.

Sterkte, ouboet! Let us know how it works out. I suggest a call to Koos Barnard at Magnum, as well as Johan Loubscher at Somchem.

Rikkie

Rikki is right guys. There are few powders available to the handloader in Africa. In the old days, here in the states, guys like Elmer Keith used duplex loads for the same reasons. Think about it. IF you only had IMR4895 & 4350 & wanted something in the middle as far as burning rate, the same charge of each mixed together, should yield a rate in between. I am putting this out as theory, but it does sound right. I think we are spoiled here & take our shooting / reloading for granted.
I wouldn't duplex load, but then again I don't have to. Good luck Berger. For what it's worth I would try a thorough mix before placing in the case. Use 1/2 the starting loads for each & work up. As one of the other guys said, a crono & preassure gauge would be a real asset.