Duplex Powder

Started by quigleysharps4570, January 06, 2012, 01:12:57 PM

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Trailrider

I do NOT shoot either duplex loads or BP in my cartridge guns, but an interesting aside:  For many years (don't know if it is still done) ballistic actuated ordnance devices (ejection seat cartridges, takeup reels on F-104 jet fighter ejection seat boot retrators, etc.) utilized A4B BLACK POWDER as an initiator charge for the smokeless final stage propellants and gas generation devices! Just thought you might like to know.  The BP charge was separated from the main smokeless grain (not grannules, just a single grain).
Ride to the sound of the guns, but watch out for bushwhackers! Godspeed to all in harm's way in the defense of Freedom! God Bless America!

Your obedient servant,
Trailrider,
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Southern District
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PJ Hardtack

Beauregard

Point taken re: 'who flung dung'. I believe I have a record of being civil and erudite on public forums, but I do respond in kind when attacked or abused. Cyber bullies are no different than the school yard variety.

Having recently blown up your gun, I can understand your apprehension about duplexing or any other reloading practice that takes you out of your comfort zone. Good - that fear will keep you safe.

How much more evidence do you require that duplexing "significantly improves performance without sacrificing safety"? My experience, that of others and references such as I quoted from "The Breech-Loading Single-Shot Rifle" by Major Ned Roberts and Ken Waters are obviously not impressing you.

If long strings of duplex loads without adverse effects on rifle, brass or shooter, great accuracy and minimal barrel fouling don't convince you, what will it take? Do not construe this an attempt to convert you to duplexing against your better will and judgement. A man's gut is one thing in life that will not lie to him. I trust my gut feelings implicitly, and I don't go where it tells me not to.
You could contact Steve Garbe at Black Powder Cartridge News for his views on the topic. He knows whereof he speaks and does so with 'been-there-done-that' authority.

As for it being an unnecessary complication, it is just one more step in an already complicated process. I first charge cases with the smokeless, block check and then charge with drop tubed BP and compress. Since I am using my 'lectronic Lyman DPS III powder dispenser for the BP, I have sufficient time between charges to drop the smokeless charge, but I feel safer not doing so.

That's me listening to my gut feeling .... ;>)
"I won't be wronged, I won't be insulted, I won't be laid a hand on.
I don't do these things to others and I require the same from them."  John Wayne

Beauregard Hooligan

Quote from: PJ Hardtack on January 09, 2012, 12:13:17 PM
Beauregard

Point taken re: 'who flung dung'. I believe I have a record of being civil and erudite on public forums, but I do respond in kind when attacked or abused. Cyber bullies are no different than the school yard variety.

Having recently blown up your gun, I can understand your apprehension about duplexing or any other reloading practice that takes you out of your comfort zone. Good - that fear will keep you safe.

How much more evidence do you require that duplexing "significantly improves performance without sacrificing safety"? My experience, that of others and references such as I quoted from "The Breech-Loading Single-Shot Rifle" by Major Ned Roberts and Ken Waters are obviously not impressing you.

If long strings of duplex loads without adverse effects on rifle, brass or shooter, great accuracy and minimal barrel fouling don't convince you, what will it take? Do not construe this an attempt to convert you to duplexing against your better will and judgement. A man's gut is one thing in life that will not lie to him. I trust my gut feelings implicitly, and I don't go where it tells me not to.
You could contact Steve Garbe at Black Powder Cartridge News for his views on the topic. He knows whereof he speaks and does so with 'been-there-done-that' authority.

As for it being an unnecessary complication, it is just one more step in an already complicated process. I first charge cases with the smokeless, block check and then charge with drop tubed BP and compress. Since I am using my 'lectronic Lyman DPS III powder dispenser for the BP, I have sufficient time between charges to drop the smokeless charge, but I feel safer not doing so.

That's me listening to my gut feeling .... ;>)

Thank you for the reply. I obviously need to learn about duplex charges, and "The Breech-Loading Single-Shot Rifle" by Major Ned Roberts and Ken Waters seems to be a good place to start. I'll find a copy, and start reading up. When I have questions, if you don't mind, I'll drop you a question or two. I'm at the "it's never too late to learn" stage in life. Thank you for taking the time to help me, and the others that are reading this, to learn a firearms science that is obviously worth learning. You can teach an old dog new tricks. Thanks again. ;)
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Stockton, Ca.

w44wcf

P J Hartack is entirely correct  when it comes to duplex loading.  In the early days, DuPont No 1 Bulk smokeless (introduced in 1893) was used. It had a burning rate similar to today's 4198.

"Swollen case heads" can only come from USING THE WRONG SMOKELESS POWDER! DO NOT USE anything faster than 2400, nor more than 10% of the total charge weight.

Back in 1980, when the 3rd Lyman Cast Bullet Handbook came out, they included data on some duplex loads in the 45-70 using SR4759 powder including pressure data.

That data proves that the practice is totally safe when the proper components and ratios are used. ;D

w44wcf
aka Jack Christian SASS 11993 "I can do all things through Christ who strengthens me." Philippians 4:13
aka John Kort
aka w30wcf (smokeless)
NRA Life Member
.22 W.C.F., .30 W.C.F., .44 W.C.F., .45 Colt Cartridge Historian

Grapeshot

I have read Paul Mathews books on the .45/70 and loading Black Powder and he used an SR prefixed powder.  I do not have that reference in front of me as I am in Iraq.  However, I have read some of the works of Elmer Keith and IIRC using a Charge of 10% of the total weight of the powder charge required, 4Fg was found to be good to get a clean burn because of the 4Fg's burn rate.

I own and shoot a Navy Arms Rolling Block .45/70 and have used this combo both with Goex 2Fg and Pyrodex and a Winchester .45-60 that I've tried with this formula and found that I can extend my accurate shooting to around 10 -15 rounds before having to punch the bore with a damp patch.

By definition, is this recipie of 4Fg and 2Fg a duplex load?
Listen!  Do you hear that?  The roar of Cannons and the screams of the dying.  Ahh!  Music to my ears.

PJ Hardtack

Grapeshot

Keith may have been aware that there were even triplex loads of compressed BP made up during the Civil War. The idea was higher velocity and a cleaner burn by utilizing powders with different burn rates - fastest at the bottom, slowest at the top.

It didn't last, as it was a PITA to manufacture on a mass basis, and the advantage gained was insignificant.
"I won't be wronged, I won't be insulted, I won't be laid a hand on.
I don't do these things to others and I require the same from them."  John Wayne

Dick Dastardly

The Lyman book lists a 5% charge of IMR 4759 powder under the black powder.  I've been using it with total satisfaction.  Since I shoot Big Lube®LLC bullets exclusively, I find that the copious quantity of lube along with the duplex load gives me excellent accuracy with no need to swab the bore, use blow tube or push patches thru.  My rifle is a fine old Remington Rolling Block that's been rebuilt and barreled with a Green Mountain 45-70 barrel.

I'm having equal or better results with my Legendary Frontiersman 38-55 and the same kind of duplex loads.  The 38-55, for reasons I don't understand, is one of the most accurate guns I've ever owned.  It shoots bp loads and duplex bp loads equally well.  Of course, I'm also shooting Big Lube®LLC bullets in it.

So, Lyman has detailed a fine duplex load.  NO, I wouldn't go experimenting with unlisted duplex loads.  I leave that for the brave of heart.  But, the load I found in the old Lyman manual is serving me well.

DD-MDA
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