Mixed powder loads

BoogieMan · June 21, 2013, 10:10 AM

I am not advocating nor have I ever tried this. I am wondering if there are any mixed powder loads. Something like using trailboss to fill the space and power pistol for the power in a cartridge. Has anyone ever tried it? Is there any posted data known? Is there any reason to do such a thing?

**Mike Irwin** · June 21, 2013, 11:09 AM

You're asking about duplexing.

It's not for your average reloader.

Small changes to one of the powders in a duplex charge can be HUGE differences in internal ballistics.

Most duplex loads are brewed up for one specific case/primer/bullet combination for one specific firearm.

CleanDean · June 21, 2013, 11:20 AM

I just now see an image. It is a cartoon balloon above a (reloader) novice's head.
The robot, from "LOST IN SPACE"....saying.......''Danger, Danger, Will ROBINSON."

BoogieMan · June 21, 2013, 11:48 AM

Quote:

I just now see an image. It is a cartoon balloon above a (reloader) novice's head.
The robot, from "LOST IN SPACE"....saying.......''Danger, Danger, Will ROBINSON."

Im not advocating it or even considering trying it. To date I have used 2 powders in 2 cartridges. For the sake of conversation I wanted to know if its been done or if there was a reason to try it.

dahermit · June 21, 2013, 11:59 AM

It has been done, but the kicker is, there is no good reason for 99.9% of handloaders ever to do it. The .1% are those with the proper ballistic equipment to do so. But even that begs the question: "Why"?

chiefr · June 21, 2013, 12:02 PM

If you want to fill the space in between, there is plenty of info on dacron and other waddings in reloading manuals.

Mixing powders is dangerous.

BigJimP · June 21, 2013, 01:18 PM

No, its too dangerous to try something like that..../ There is really no way to predict what might happen...with any degree of certainty in my opinion.

---- and there is no practical reason to do it...

There are powders that work well with low volume charges in large volume cases ( like TiteGroup in .44 Mag ).....

Rangefinder · June 21, 2013, 06:18 PM

Duplex loading is used wen a primary powder is an extremely slow-burning/difficult to ignite powder in a large-capacity case. A light charge of fast powder is compressed against the flash-hole (usually in the neighborhood of .5-1 grain) to act as a "supercharged primer". These types of loadings are not only uncommon, but extremely dangerous in anything but expert hands. If you aren't already very familiar with the practice, you aren't anywhere NEAR experimenting with it.

JerryM · June 22, 2013, 08:38 AM

I recall Elmer Keith writing about his duplex loads in the OKH cartridges. He even soldered or welded tubes inside the cartridge cases so that the fire from the primer would get to the top. He put faster burning powder at the top, and then the slower powders. He claimed some velocities that I don't really believe. None were chronographed.

I cannot imagine the trouble and problems with doing such things, but that is what experimenters do. They give us some good ideas also, and more power to them.

Jerry

snuffy · June 22, 2013, 11:12 AM

First off, the powders are not MIXED! They are layered. The fast pistol/shotshell powder is held at the bottom of the case, tight against the powder. Then the main charge is dropped in, it is a 100% density load, sometimes a compressed load. So the fast powder can't move/mix with the slow powder.

Common application is when using surplus ultra slow cannon type powder in magnum cartridges like 300 win mag. WC-870 was used for the vulcan 20 mm. While using it alone can work with really heavy 30 cal. bullets 200+, it works much better with a booster charge of fast powder under it.

Even with my 50 years of reloading experience, I'm scared to try it! Without a pressure testing set-up, you'd be stumbling around in the dark. I like to shoot my rifles, NOT WEAR them.

buck460XVR · June 22, 2013, 01:24 PM

BoogieMan....as other's have said, Duplex loading is something that is done, but not by the average handloader, nor is it just to fill the case. If you are concerned about low volume powders, there are many other options out there for powders that give similar performance with more volume as opposed to experimenting with "duplex" loads. Most folks that use powders with low charge weights do it because of the economics, i.e. getting more rounds outta a pound of similar priced powder, and not because of performance. A prime example would be Unique and 2400 when used in .44mag. Both powders cost about the same per pound, but one can get twice as many similarly performing mid range rounds outta a pound of Unique than 2400. If one shoots thousands of mid range .44 rounds every year, one is talking about getting 700 rounds per pound as opposed to 350 rounds. The savings can be quite significant. But to me, the hassle and dangers involved in trying to duplex loads would not be worth the cost savings vs using a higher volume powder.

Marco Califo · June 22, 2013, 09:46 PM

Quote:

Common application is when using surplus ultra slow cannon type powder in magnum cartridges like 300 win mag. WC-870 was used for the vulcan 20 mm. While using it alone can work with really heavy 30 cal. bullets 200+, it works much better with a booster charge of fast powder under it.

Yes, I have done this after many years of reloading. The results were OK, but without a chronograph, there is still too much guess work. I am taking a break from it until I have access to a chrono. Anyway, I got an elk tag this year, so, I am sticking with 165-180 gr 308 with conventional (single powder) loads, exclusively until 2014.

To reiterate what others have said, you have no reason to even think about doing this. Not unless you already knew and understood what everyone here is saying. But in that case, you would not have asked this question, at least not with starting by telling us what you want to do, and why you want to, as well as why you even think it makes any sense.

June 21, 2013, 10:10 AM	#1
BoogieMan Senior Member Join Date: April 4, 2012 Location: South Jersey Posts: 2,217	Mixed powder loads I am not advocating nor have I ever tried this. I am wondering if there are any mixed powder loads. Something like using trailboss to fill the space and power pistol for the power in a cartridge. Has anyone ever tried it? Is there any posted data known? Is there any reason to do such a thing? __________________ Concentrated power is not rendered harmless by the good intentions of those who create it. Milton Freidman "If you find yourself in a fair fight,,, Your tactics suck"- Unknown

June 21, 2013, 11:09 AM	#2
Mike Irwin Staff Join Date: April 13, 2000 Location: Northern Virginia Posts: 41,390	You're asking about duplexing. It's not for your average reloader. Small changes to one of the powders in a duplex charge can be HUGE differences in internal ballistics. Most duplex loads are brewed up for one specific case/primer/bullet combination for one specific firearm. __________________ "The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza Baby Jesus cries when the fat redneck doesn't have military-grade firepower.

June 21, 2013, 11:20 AM	#3
CleanDean Member Join Date: March 18, 2012 Location: Penna◇VIGILANT CURMUDGEON Posts: 80	I just now see an image. It is a cartoon balloon above a (reloader) novice's head. The robot, from "LOST IN SPACE"....saying.......''Danger, Danger, Will ROBINSON." __________________ FNH Scar 17 s --Black ; cause it goes so well with my formal wear, for those special occasions. Customized Mini 14 ,& ATI stock and a 3.5 lb.-- Pittsburgh trigger. / SIG P227 / Colt Python 8 in.Nickel / Colt Gold Cup N.M. ; Voere * KDF in .270 ; N. frame S&W revolvers; and TC Contender in 41 Magnum .

June 21, 2013, 06:18 PM	#8
Rangefinder Senior Member Join Date: August 4, 2005 Posts: 2,017	Duplex loading is used wen a primary powder is an extremely slow-burning/difficult to ignite powder in a large-capacity case. A light charge of fast powder is compressed against the flash-hole (usually in the neighborhood of .5-1 grain) to act as a "supercharged primer". These types of loadings are not only uncommon, but extremely dangerous in anything but expert hands. If you aren't already very familiar with the practice, you aren't anywhere NEAR experimenting with it. __________________ "Why is is called Common Sense when it seems so few actually possess it?" Guns only have two enemies: Rust and Politicians.

June 22, 2013, 08:38 AM	#9
JerryM Senior Member Join Date: April 4, 1999 Location: New Mexico Posts: 1,889	I recall Elmer Keith writing about his duplex loads in the OKH cartridges. He even soldered or welded tubes inside the cartridge cases so that the fire from the primer would get to the top. He put faster burning powder at the top, and then the slower powders. He claimed some velocities that I don't really believe. None were chronographed. I cannot imagine the trouble and problems with doing such things, but that is what experimenters do. They give us some good ideas also, and more power to them. Jerry __________________ Ecclesiastes 12:13 ¶Let us hear the conclusion of the whole matter: Fear God, and keep his commandments: for this is the whole duty of man. 14 For God shall bring every work into judgment, with every secret thing, whether it be good, or whether it be evil.

June 21, 2013, 11:59 AM	#5
dahermit Senior Member Join Date: October 28, 2006 Location: South Central Michigan...near Posts: 6,501	It has been done, but the kicker is, there is no good reason for 99.9% of handloaders ever to do it. The .1% are those with the proper ballistic equipment to do so. But even that begs the question: "Why"?

June 21, 2013, 12:02 PM	#6
chiefr Senior Member Join Date: January 27, 2010 Location: AR Posts: 1,401	If you want to fill the space in between, there is plenty of info on dacron and other waddings in reloading manuals. Mixing powders is dangerous.

June 21, 2013, 01:18 PM	#7
BigJimP Senior Member Join Date: February 23, 2005 Posts: 13,195	No, its too dangerous to try something like that..../ There is really no way to predict what might happen...with any degree of certainty in my opinion. ---- and there is no practical reason to do it... There are powders that work well with low volume charges in large volume cases ( like TiteGroup in .44 Mag ).....

June 22, 2013, 11:12 AM	#10
snuffy Senior Member Join Date: May 20, 2001 Location: Oshkosh wi. Posts: 3,055	First off, the powders are not MIXED! They are layered. The fast pistol/shotshell powder is held at the bottom of the case, tight against the powder. Then the main charge is dropped in, it is a 100% density load, sometimes a compressed load. So the fast powder can't move/mix with the slow powder. Common application is when using surplus ultra slow cannon type powder in magnum cartridges like 300 win mag. WC-870 was used for the vulcan 20 mm. While using it alone can work with really heavy 30 cal. bullets 200+, it works much better with a booster charge of fast powder under it. Even with my 50 years of reloading experience, I'm scared to try it! Without a pressure testing set-up, you'd be stumbling around in the dark. I like to shoot my rifles, NOT WEAR them. __________________ The more people I meet, the more I love my dog They're going to get their butts kicked over there this election. How come people can't spell and use words correctly?

June 22, 2013, 01:24 PM	#11
buck460XVR Senior Member Join Date: December 28, 2006 Posts: 4,342	BoogieMan....as other's have said, Duplex loading is something that is done, but not by the average handloader, nor is it just to fill the case. If you are concerned about low volume powders, there are many other options out there for powders that give similar performance with more volume as opposed to experimenting with "duplex" loads. Most folks that use powders with low charge weights do it because of the economics, i.e. getting more rounds outta a pound of similar priced powder, and not because of performance. A prime example would be Unique and 2400 when used in .44mag. Both powders cost about the same per pound, but one can get twice as many similarly performing mid range rounds outta a pound of Unique than 2400. If one shoots thousands of mid range .44 rounds every year, one is talking about getting 700 rounds per pound as opposed to 350 rounds. The savings can be quite significant. But to me, the hassle and dangers involved in trying to duplex loads would not be worth the cost savings vs using a higher volume powder.