??Duplex and Triplex loads?? Am I talking crazy?

[WR Moore]

A couple of folks mentioned the extended primer flash tubes. The inspiration for that came from artillery rounds. The primer was extended to just short of the shell/projectile base so that the powder would burn from the front back and produce a more complete burn. Burning from the base could/would cause more unburned powder to be ejected from the bore. At least that was the theory for artillery.

BTW. at least in the 105 mm shell, the flash holes are mind boggling.

 

[max]

This thread has sent me out for research. What I am reading, the 454 Casull uses a small rifle primer.

COTW gave a triplex load for the .454 Casull in earlier editions, but later editions went back to single propellant loads only using H110, 2400, and 296 respectively for 250, 260, and 300 gr JHP bullets. Large Rifle primers were recommended. Unique was recommended for use with lighter 200 and 225 gr JHP bullets.

I can't think of a single reason that I would ever buy a .454 Casull revolver.

 

[6string]

You wouldn't want to shoot a 30-30 in a pistol, but you're interested in trying duplex or triplex loads?

I get it...
Just another "click bait" thread.

 

[Imissedagain]

WWII prisoners of war, stateside, made ash trays from artillery shells with those long primer tubes.
My Dad kept them busy.

Didn't have to be a rocket scientist to realize that if the artillary didn't get you overseas, the Camels would at home.
Sad but true.

Duplex loads for the 458 WinMag was interesting reading years ago, as the PDG hunters were trying to get it up to speed back in it's early days.

 

[DWalt]

This thread has sent me out for research. What I am reading, the 454 Casull uses a small rifle primer.

I believe that later cases did use the small primer, and there was also a small primer bushing for the cases having large primer pockets

 

[STORMINORMAN]

If a Ruger (or a S&W) revolver was available in 454 Casull for the same price as chambered in 45 Colt, I, for one, would buy it in the alternative...

Jus' sayin'...?

Cheers!

 

[ArchAngelCD]

I'm hoping everyone here realizes how dangerous this can be. The loaders and inventors back then were pioneers and most had the availability of pressure testing equipment.

With the plethora of powers available today in every small powder speed spread there is no reason to use duplex or triplex loads today.

Anyone inspired but this thread please don't or be extremely careful under safe testing conditions...

 

[TexasViking]

Internal ballistics are well studied and all the mathematics were well established in the relatively early in the 1900's.

Here is a list reading material/references that will help you better understand what is happening once the primer is ignited.

Once you start to understand the basics you should be able to see the limitations of concepts like duplex loads, primer extension tubes and the numerous other experiments that individuals concoct.

If any of these really were reasonable successful the would be common in the market place.

"Interior Ballistics of Guns" Engineering Design Handbook Gun Series, AMCP 706-150, 1965
This is a more serious effort and is on a par with Hunt's "Internal Ballistics" i. The experimental methods described date from the WWII. This is available online

F. R. W. Hunt "Internal Ballistics" The Philosophical Library, 1951
An edited collection of contributions by a number of British ballisticians. It goes into the basic theory of internal ballistics with a good description of the experimental work and methods. This is available online

J. Corner "The Theory of the Interior Ballistics of Guns" Wiley, 1950
The "classic" text on the theory of internal ballistics. A statement of the state of the art in British research at the end of WWII. This is available online.= a must for students of internal ballistics bookshelf

If you are interested in an expanded list PM me

Good stuff, and I don't know if you're familiar with Quik Load, but it gives a value for "Time to PMax" that might disagree about Peak Pressure occurring before the bullet has left its case. Regardless, people believe that SAAMI are Apostles who lay down the Gospel.
In a conversation I had with Johan Loubser in 2001, when he was with Accurate Powders, before the Western acquisition - getting Johan in the bargain - he was convinced that SAAMI would adopt the CIP method of pressure testing. Not long after the acquisition he retired back to his native land, and 21 years later, SAAMI is still SAAMI. Kind of like the old tune, "If you knew Suzie, like I know Suzie."
Yet all of the NATO cartridges have their pressures established by the CIP method that looks at internal combustion rather than case expansion.
Thinking you my have read a thing or 2 about Dr. Bull and his Supergun research?

 

[ruggyh]

Good stuff, and I don't know if you're familiar with Quik Load, but it gives a value for "Time to PMax" that might disagree about Peak Pressure occurring before the bullet has left its case. ....

Yes I am familiar with Quick Load and "Time to PMax" values.
A very good tool, feel free to explore the Pmax values for straight wall handgun cartridges (using published) data please report back any loading where the peak is reached after the bullet has left the case.

he was convinced that SAAMI would adopt the CIP method of pressure testing. Not long after the acquisition he retired back to his native land, and 21 years later, SAAMI is still SAAMI. Kind of like the old tune, "If you knew Suzie, like I know Suzie."
Yet all of the NATO cartridges have their pressures established by the CIP method that looks at internal combustion rather than case expansion. ......

and the debate rages on
If you look at each they have some issues.

Both meet the intent I would say- provide baseline information for the safe manufacturing of ammunition.

Thinking you my have read a thing or 2 about Dr. Bull and his Supergun research?

Read some, yes- not really a fan. He was just applying know mathematics to solve different external ballistics problems - and tackling material engineering problem that arose with the scale of projectiles- nothing new came out of the research with regards to internal ballistics.

 

[WR Moore]

Sometime back there was a long thread or two here on SAAMI/CIP/DOD pressure testing that went really deep into the weeds. My recollection is that they're all very slightly different in measurement methods.

Having said that, the reason SAAMI & CIP remain different is pretty much the same reason the DOD tests velocity at 78 feet instead of the usual 15 feet: It'd be an enormous, time and money draining pain to redo all the testing and rewrite all the documentation and standards.

 

[mtgianni]

I have used some duplex loads with non canister powders in rifles, In essence you use 3-6 gr of a fast rifle powder to help ignite surplus 50 bmg powder.

In the instance shown above, 2400 is really easy to ignite and should not need either a kicker or a finisher, IMO. If you want to experiment with duplex loadings, try a small amount of FFF under a slightly smaller than normal load of FF with a rb in a muzzleloader.

 

[IAM Rand]

This is without doubt the dumbest thread I ever read.

So dumb that you had to reply to it. Just like the earth is flat and don't go too far in a ship, you might fall off the edge.

I have read 1 article about it and was asking if someone here might have had any experience with it. Obviously there are people that have had some experience either by reading about it or someone actually doing it. Soooooooo, I guess that they don't believe it is so dumb to talk about it.

Also, I guess that Mr. Keith was dumb to load up 44spl cases to mag loads, some times blowing up his pistol. If he didn't, we wouldn't have the 44 mag or the 357 mag.

But, you are correct, this is just a dumb topic.

 

[IAM Rand]

The loaders and inventors back then were pioneers and most had the availability of pressure testing equipment.

Agree and disagree. The loaders back then were pioneers but, if they did have the availability of pressure testing equipment they didn't use it. Elmer Keith, from what I have read, had blown up more than one pistol in his experiment with pushing 44 special loads to the max. I have a feeling that some of his compatriots also did the same a time or 2.

 

[BigMuddy]

Yes, Dick Casull used triplex loads when first developing his "super charged" 45 Colt loads/gun. He also said after H110 powder became readily available there was no need. He was exceeding 44 mag performance before there was a 44 Mag. He was a brilliant man with exceptional machining skill and knowledge. When his special heat treated Colt SAA didn't give him the performance he was looking for, he built a revolver from bar stock.

And yes the 454 uses small rifle primers. The change to SRP was to aid in containing the pressure more than to improve ignition. I have a box of 50 FA Casull brass that take large pistol primers.

I don't "need" a 454 either, but sure do like mine.

Dan

 

[GypsmJim]

You wouldn't want to shoot a 30-30 in a pistol, but you're interested in trying duplex or triplex loads?

I get it...
Just another "click bait" thread.

My hunting gun is a Encore handgun in 0.308. It has taken many a deer. But the barrel is designed for that caliber and I load the cartridges to Handbook specs.

 

[smoothshooter]

Duplex loading has been used in the large 1800's black powder cartridges ever since the advent of smokeless powder.
Shooters would drop 3 to 5 grains of a fast burning type of smokeless into the cartridge case, with enough of a charge of black powder on top so that the charge was compressed some when the bullet was seated.
When this method is used, it causes the black powder to burn more efficiently and virtually eliminated the fouling in the bore.
I have seen this with my own eyes. Amazing how well it works.
I do not see any practical value in duplex smokeless loads in a handgun. If done, I think the charge would need to fill up the case and be a compressed load so the different powders cannot move around and mix.

 

[Drm50]

I never did duplex or triplex loads. I could never get my mind wrapped around 3 different burn rates, loose in a case, that was not a compressed load. Some used flash paper disc to keep them separated.
Speaking of straight cased cartridges there seems to be a threshold you reach that is end of practical velocity.
Having no intentions of blowing up a good gun if for some reason I needed extra power, I would just buy a bigger gun.

 

[Baltimoreed11754]

Never messed with multiple powders in a single reload but I have experimented with multiple projectiles in a .45colt case. They would impact the target fairly close together.

 

[Ivan the Butcher]

P.O. Ackley's reloading book has Cassel's duplex and triplex 45 Colt loads listed. But not for handguns! They are listed in the rifle section for Winchester 92's! They appear to be very good bear medicine!

Ivan

 

[IAM Rand]

You wouldn't want to shoot a 30-30 in a pistol, but you're interested in trying duplex or triplex loads?

I get it...
Just another "click bait" thread.

Huh, no. Serious thread. I am specifically looking at pistol cartridges because I have a 460 XVR. In my searching I saw info about duplex and triplex. Don't care if you or anyone else checks out the thread. Just interested if anyone here was dabbling in this or knew someone that was/had.

I deeply apologize that you had to spend a whole 5 minutes of your day reading this. Had I the ability to give you 5 minutes back I would.