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

[ruggyh]

.....
Speaking of straight cased cartridges there seems to be a threshold you reach that is end of practical velocity. ....

We have a winner.

 

[DWalt]

The only "duplex" load I have worked with is adding about 10% black powder to Pyrodex. It really improves ignition in ML rifles and C&B revolvers.

 

[Green Frog]

Duplex loads were popular enough that Ideal and later Lyman made powder measures specifically to drop first the small "kicker" charge, then a second "main" charge. The early measure was the #2, IIRC, and the later, better known one was the #6. The practitioners of the single shot rifle game ("Schuetzen") in the late 19th and early 20th Century frequently used this method, for instance using a small charge of fast burning powder (usually smokeless) under a larger, main charge of black powder or a slower burning, large grained smokeless. Triplex loads were less common, but not unheard of… some loaders used the #4 Ideal powder measure that was actually designed for duplex loaded shot shells.

For me, it was interesting in antique rifles and almost mystical in modern handguns. Impressive but not something I'm like to ever do myself.

Froggie

 

[STORMINORMAN]

"If I could save time in a bottle..."

Cheers!

 

[TexasViking]

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.

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.

I don't recall making an empirical statement, so I'll leave it to you to supply the data that proves yours. Since you're aware that it predicts time to PMax, than you're also likely aware that it predicts the bullet time in the bore. Easy enough to compare since a near instantaneous PMax would be but a small fraction to bullet time in bore.

I mentioned Dr. Bull relative to this thread because no powders have ever been quite as exotic as those made for the SuperGun project in Belgium, and possibly PB Clermont who supplies several powders that are branded Ramshot. True Blue is the commercial version of the powder created for FN Herstal and the 5.7 x 28mm. He certainly used known mathematics relative to physics. and definitely studied the extremely long range "Paris" guns developed by the Germans, but Bull was pursuing ranges and accuracy never seen before or since. While he was Canadian, he was given US citizenship while working under contract for the military. But an outsider in terms of the Military/Industrial Complex that swayed the US Military towards ballistic missiles at a time when there were no anti-ballistic missiles. He certainly proved that he could achieve ranges previously unseen, with the very likely possibility of intercontinental ballistics.

 

[Beemer-mark]

Been reloading for more than 40 years. I can remember these kinds of loads. My only comment is ARE YOU CRAZY

 

[TexasViking]

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.

I'd like to comment on a couple of your "qualifiers," Straight Wall handgun cases and published data, which I do use but may pre-date yours since I was handloading several years before SAAMI did the switcheroo with the 9 x 19mm. Even allowing a few thousandths of an inch there are very few cartridges that are truly "straight wall." I'm okay with revolver cartridges and the ACPs, but obviously the 9 x 19mm is not a straight wall case. I've seen similar claims about Pressure Peak before, so this ain't my first rodeo. And I have mentioned that I like to recommend that every handloader should have at least one Lyman manual. The Lyman 46th Edition (Copyright 1982) debunks the entire myth in an article titled "A Limited Comparison of the Crusher and Piezo systems" and includes some nice illustrations where the chamber is certainly "Straight Wall." That article clearly shows that the bullet is into the rifling before pressure peak occurs, and that the bullet leaves the case before 10,000 PSI has been reached. So since you did say "Please report back."

 

[ruggyh]

I'd like to comment on a couple of your "qualifiers," Straight Wall handgun cases and published data, which I do use but may pre-date yours since I was handloading several years before SAAMI did the switcheroo with the 9 x 19mm. Even allowing a few thousandths of an inch there are very few cartridges that are truly "straight wall." I'm okay with revolver cartridges and the ACPs, but obviously the 9 x 19mm is not a straight wall case. I've seen similar claims about Pressure Peak before, so this ain't my first rodeo. And I have mentioned that I like to recommend that every handloader should have at least one Lyman manual. The Lyman 46th Edition (Copyright 1982) debunks the entire myth in an article titled "A Limited Comparison of the Crusher and Piezo systems" and includes some nice illustrations where the chamber is certainly "Straight Wall." That article clearly shows that the bullet is into the rifling before pressure peak occurs, and that the bullet leaves the case before 10,000 PSI has been reached. So since you did say "Please report back."

You welcome to use any published load data with out regard to it meeting any standard, put must not exceed the cartridges design pressure.

I use the term strait wall because the vast majority of industry uses the term. Yes most these cases may have some tapper.

You seem to hung up with SAAMI - You are the only one seeming to want to reference them - I am confused. If your preference is use some other method then that would be your choice and has little to do with original discussion.

As I stated previously they meet the intent of a standard. None are perfect.

Now you would like to introduce copper crushers vs. piezo by siting an article that is 40 years and the beginning of the solid state pressure devices. The devices are much evolved today by comparison and the article holds little water today.

Crushers data is difficult to replicate, even by the same operator.
I have seen tech's argue the value of the same impression by 10Kpsi. Their is good reason CIP, SAAMI, and government labs have left them behind for small arms ammunition.

Personally have piezo and stain gauges, each work and generates repeatable data. Data does vary depend on the method used but this is inherent due to variability of tools and procedure used. Most my experience is with large cross section area high pressure handgun cartridges ie. 460 S&W magnum.

As for pMax in Quickload (QL) and other simulation tools (in strait wall cartridges) they show the bullet has not left the before pMax for the cartridges I am familiar with, I make no claim to have reviewed all of them.

If you know of a exception please present it.
Please note the verison of QL used and I will post the quick curve for your example (I have the last 3 versions independently loaded). If 9x19 is your example I will look into that cartridge in detail and see if it proves out. A fast powder with a short light bullet might just make it out.

Apologizes to the OP for diverting from his discussion.

 

[TexasViking]

You welcome to use any published load data with out regard to it meeting any standard, put must not exceed the cartridges design pressure.

I use the term strait wall because the vast majority of industry uses the term. Yes most these cases may have some tapper.

You seem to hung up with SAAMI - You are the only one seeming to want to reference them - I am confused. If your preference is use some other method then that would be your choice and has little to do with original discussion.

As I stated previously they meet the intent of a standard. None are perfect.

Now you would like to introduce copper crushers vs. piezo by siting an article that is 40 years and the beginning of the solid state pressure devices. The devices are much evolved today by comparison and the article holds little water today.

Crushers data is difficult to replicate, even by the same operator.
I have seen tech's argue the value of the same impression by 10Kpsi. Their is good reason CIP, SAAMI, and government labs have left them behind for small arms ammunition.

Personally have piezo and stain gauges, each work and generates repeatable data. Data does vary depend on the method used but this is inherent due to variability of tools and procedure used. Most my experience is with large cross section area high pressure handgun cartridges ie. 460 S&W magnum.

As for pMax in Quickload (QL) and other simulation tools (in strait wall cartridges) they show the bullet has not left the before pMax for the cartridges I am familiar with, I make no claim to have reviewed all of them.

If you know of a exception please present it.
Please note the verison of QL used and I will post the quick curve for your example (I have the last 3 versions independently loaded). If 9x19 is your example I will look into that cartridge in detail and see if it proves out. A fast powder with a short light bullet might just make it out.

Apologizes to the OP for diverting from his discussion.

Well, Pard, ammo pressure testing by the major US manufacturers has not changed since then. Several companies like Hodgdon still test in CUP. many test in both CUP and Piezo PSI including simultaneously. If it were up to me they'd be testing in CIP like the Europeans. And the pressure rating for the 9 x 19mm should be 36,500 PSI/CIP so we could all just refer to one cartridge that most quality pistolmakers are making their pistols for anyway. 9mm NATO.

The issue with SAAMI is my own. Most bullet-makers, the majors anyway, are also in the ammo biz now, several of them providing handload manuals (with NO pressure data) with each successive manual getting its loads reduced from even the previous edition. I definitely believe we need a solid safety organization. What we don't need is obfuscation. And I didn't bring it up as a topic of debate in any case.

I've never had any QuikLoad program other than the demo and copies of analysis handloaders have sent me for review. Frankly, I don't need it or BS opinions.

 

[cmj8591]

You have to keep the small arms research about duplex loads in context. It came from a time when there were maybe four burning speeds for small arms propellants. Necessity is the mother of invention. Now there are many powders available for about every imaginable circumstance. As a handloader, I'm not sure what the practical application would be for me using duplex loads. I can see where it would add extra steps to the loading process that probably wouldn't amount to enough gain in performance to justify using it. However, one of the reasons a lot of us do this reloading thing is the ability to experiment with different aspects of ballistics. I say if you're comfortable enough with your loading skills and knowledge, go for it. This might be a good subject to bring to the loading bench now that the days are getting shorter and there's more free time.

I find the discussions about Bull interesting. His research was relevant for it's time but rocket science rendered it mute on the scale he was operating. One thing it did do was get the attention of the MOSSAD, who stopped by his apartment to discuss some of the finer points.

 

[Pisgah]

Richard Casull demonstrated years ago how to disassemble a revolver with duplex/triple loads. I see no need to advance the research on this technique ...