New VS Old Unique

[BC38]

OK, well if the general consensus is that the old and new are the same charge weight for charge weight, I'll use modern load data even when I start using the old powder.

When I saw the data in the old manuals I figured that I needed to load using that data once I started using the old powder. I guess that really isn't necessary or even the right way to go...

 

[Nemo288]

Manufacturers and distributors actually try really hard to keep a powder's performance stable even if the formula and/or process changes.
There have been a few occasions, especially with powders that started out as surplus, where this was not the case.
Also confusing is where you have 2 powders with almost the same name that ARE different.
Example I experience would be IMR and H 4198
H4198 is denser and burns a little slower, even looks different.
Then there is the plethora of 4350 powders....

Considering Unique is one of the early canister powders (Laflin & Rand 1900) I think they have done a good job keeping it stable.
I wonder if this is the case with say IMR 3031 (1934).

===
Nemo

 

[Alk8944]

Some of the load data in the older Speer and Sierra manuals is dangerous. Most (all?) loads were not pressure tested, but if anyone wants to continue to use them, please be my guest.

The discussion is specifically about Unique. You cannot support your contention that "Most loads were not pressure tested" as it simply is not true! If you will consult Hercules/Alliant, Winchester, IMR, much (Not all!) of Hodgdon data, and some others you will find they have published published pressure data! You can take it to the bank that this information was derived by some pressure measurement system at some time! They did not simply pick numbers out of the air.

 

[BC38]

Some of the load data in the older Speer and Sierra manuals is dangerous. Most (all?) loads were not pressure tested, but if anyone wants to continue to use them, please be my guest.

I can neither conform nor deny these statements. However, FWIW, the 33% higher charge weight data I was referencing was not from Speer or Sierra - it was from the powder manufacturer's manual (Hercules 1987 & 1992).

While I can't speak to how accurate the data is - or how the numbers were derived - it DOES give pressures for each load and they are below the SAAMI standards as far as I can see/tell/recall...

 

[Nemo288]

The problem we are encountering here (warning: thread drift!) is pressure measured by copper crusher vs. piezo peak.
Crushers are a measure of total energy and no one at the time had any real idea of the instantaneous peak pressure.
Now we do and this is why loads have been reduced.
Whether or not they really needed to be is yet another question that will be debated forever.

===
Nemo

 

[BLUEDOT37]

FWIW, the 33% higher charge weight data I was referencing was not from Speer or Sierra - it was from the powder manufacturer's manual (Hercules 1987 & 1992).

Don't forget that the old SAAMI max pressure standard for the 357 Magnum was 45,000 CUP vs the current standard of 35,000 PSI. That's approximately 10,000 PSI different between them.

However, looking at the 1983 Hercules Guide vs the 2000 Alliant Guide (pressure given in kCUP vs kPSI respectively) I don't see that big of a percentage difference in the powder weights for the 357 Mag in their data. Do you have an example of that 33%> difference?

.

 

[DWalt]

Until at least 1970, CUP was about the only chamber pressure measurement method existing, at least in wide use. Starting then, the use of electronic piezo gauges became more common. I did some of the first piezo gauge pressure measurement work in the mid-late 1960s when I worked for Hercules. In those days, we had to use an oscilloscope and a Polaroid camera to take a picture of the pressure trace on the screen. Very tedious, but the data was good. CUP and piezo PSI data are not comparable. I have discussed that in some detail in other postings, so I won't do it here.

By the way, does everyone know that Unique and Bullseye use the same formulation? The difference is in the granule thickness.

 

[Nemo288]

I had read that in a history of Laflin & Rand I came across.
L&R-Smokeless-History
Fascinating stuff.
There were also a couple of other versions that have disappeared.
BTW this document also has a copy of the ad showing the original Infallible/Unique sample referred to above.

Also recommended is "The Chemistry Of Powder & Explosives"
[ame="http://www.amazon.com/Chemistry-Powder-Explosives-Tenney-Davis/dp/0913022004/"]Amazon.com: The Chemistry of Powder and Explosives (9780913022009): Tenney L. Davis: Books@@AMEPARAM@@http://ecx.images-amazon.com/images/I/51QPATJ7HDL.@@AMEPARAM@@51QPATJ7HDL[/ame]
This was written during WW2 and published about the time I was born but remains one of the most detailed
tretises on nitro-organics and other propellant processes.

I agree about the difference between CUP and PSI.
I have seen a couple of modern tests that used both methods simultaneously.
They were custom tests of double rifle rounds to try to establish what would be safe modern equivilents.
The word from them was that the CUP crusher buttons are not going to be available forever making all that old data even more of an orphan.

I also had the pleasure of trying to capture those scope traces with a Polaroid.
In my case it was for certifying bandwidth and harmonics (and other functions) of broadcast equipment.
This is one area the computer certainly has made things way easier.
Remember the competing, totally incompatible, data busses of HP and Tektronix?
My first attempt at resolving some of this was using a VIC20 which had raw FET gate I/O you had to make your own boards to interface.
Ahh the nostalgia!

===
Nemo

 

[DWalt]

I once taught a course in explosives chemistry and the Tenney Davis book was my textbook as there was nothing else like it available, at least then. Problem was that there were many newer explosives developed during and after WWII which are not mentioned in it, so I had to develop course coverage materials for those separately.

The only oscilloscopes we had were Tektronix, and they were huge at the time. Seems like they weighed a ton and had to be moved around on wheeled carts. The Polaroid camera back fit in a mounting over the face of the tube. Also needed to integrate the area under the P-T curve using a planimeter on the picture for explosive shock wave analysis. That was also tedious, as we generally did it several times and took an average.

 

[BC38]

...However, looking at the 1983 Hercules Guide vs the 2000 Alliant Guide (pressure given in kCUP vs kPSI respectively) I don't see that big of a percentage difference in the powder weights for the 357 Mag in their data. Do you have an example of that 33%> difference?

Sure, its in the very first post of this thread - to quote myself...

...the old Hercules manuals recommend higher charge weights than anything I have seen for the Alliant version of Unique. And I'm not talking just a little bit either - they are a LOT higher - like 25% more powder. For example in the Hercules manual it shows 10gr for a 110 gr 357 JHP and the load data for the same bullet with Alliant's version of Unique says to use 7.4gr!

The Hercules manual that shows 10gr for this bullet is the 1987 manual, and IIRC it was the Lyman 48th that showed 7.4 gr of modern Unique for the same bullet weight and type. Unfortunately Im not where I can get to my Lyman's manual right now to confirm...

 

[BLUEDOT37]

Oops! Sorry, guess I'm blind in one eye & can't see out of the other.

Using that example in the two Hercules/Alliant powder manuals I referenced, 1983 & 2000, they are the same in both, 10.0gr/Unique with 110gr JHP, in a 357Mag case.

In Speer #9 (1978) it's 10.0gr also. Speer #13 (1998 & before they merged with ATK) & Speer #14 (2007 & ATK partner) it's 9.7grs, as it is in the current Alliant manual. Lyman #45 (1978) & #49 (2008) both have 10.0gr. I can only surmise that the year you saw the 7.4grs in (1992?) was a typo.

.

PS: It's 10.0grs also in the 1992 Hercules manual.

.

 

[BC38]

Oops! Sorry, guess I'm blind in one eye & can't see out of the other.

Using that example in the two Hercules/Alliant powder manuals I referenced, 1983 & 2000, they are the same in both, 10.0gr/Unique with 110gr JHP, in a 357Mag case.

In Speer #9 (1978) it's 10.0gr also. Speer #13 (1998 & before they merged with ATK) & Speer #14 (2007 & ATK partner) it's 9.7grs, as it is in the current Alliant manual. Lyman #45 (1978) & #49 (2008) both have 10.0gr. I can only surmise that the year you saw the 7.4grs in (1992?) was a typo.

Well, now I'm going to have to pull out my manuals tomorrow and figure out where I got that from....

 

[Gatorbaiter]

The reason max loads are lower in modern manuals than in older manuals is because the lawyers did not proof read the older manuals before publishing.

 

[Warren Sear]

The discussion is specifically about Unique. You cannot support your contention that "Most loads were not pressure tested" as it simply is not true! If you will consult Hercules/Alliant, Winchester, IMR, much (Not all!) of Hodgdon data, and some others you will find they have published published pressure data...(blah, blah, blah)...

My comments were regarding the old Speer and Sierra manuals. I can't prove a negative, nor do I give a damn about it one way or the other, but there was not a word in the old Speer and Sierra manuals about pressure testing the loads, and no pressure data was provided. I remember reading statements like, "These loads did not show evidence of excessive pressure in our test firearm", or something to that effect. Later on, both manuals began to state pressures (in CUP). It would seem to me that this is credible evidence that the earlier data was not pressure tested on laboratory ballistic equipment.

I did not say a word about the other powder manufacturers you mentioned, even though the discussion is specifically about Unique.

 

[metalman60]

That is why old load books are useful

I keep up to date RCBS manuals on reloading. I also keep the manuals I got in 1977..... I compare old vs new. This way I double check if a new powder formulation requires that I use the latest manual.
Funny thing is, there is not much difference in pistol charges when you compare old vs new. Maybe .10 grain.

You can obtain old load books at garage sales etc.

Regards
Metalman60

 

[sniper]

Unique?

As I said above, that is pretty much my take on it based on over 50 years of reloading experience, and I act accordingly. I have absolutely no reason to believe that a load that was published by not only Alliant, but Lyman and others, since the 1930s, with no problems that could be attributed to the data, is suddenly "Dangerous" because the method of measuring pressure changed! A good example is .38 Special. 5.5 gr. Unique with a 158 gr LSWC and standard SP primer was very common since the 1930s. Literally millions of rounds with this load have been fired successfully and safely over the past 80 years. The idea that it is suddenly dangerous simply because published data has been recently changed is assinine.

I agree completely. 5.5 gr. Unique is/has been my IPSC/go to load for 50 years, I deisremember where I got the load...the infamous SPEER #8 is a real possibility. This, in 357 Magnum brass, standard primer of whatever make I could find, cast RCBS 150 gr., or 158 Gas Check. Chronoed 860 fps.

 

[venomballistics]

a LOT has happened between then and now.
One of the key things that has changed has been the use of direct pressure measurement replacing copper crusher measurement.
That change in standard made a lasting mess of things.
while our current PSI data is better, it eliminated loads and lowered standards in many cartridges. It's not as evident as it was early on, but bread crumbs remain.

 

[GypsmJim]

I started using Unique back in the 1970's. Shortly afterwards I upgraded my powder dispensing tool to a Lee Auto Disc. Then, I calibrated my measure with each type of powder I was using and plotted the data on Excel. All the curves showed a 99+% confidence factor.

Many batches of Unique went thru the system over all these years. Just last week I loaded a different formula, and went back to my calibration to set the measure. First drop, spot on.

I don't know about performance differences, but I can say for certainty that the density has not changed.

 

[pantannojack]

I would not expect a squib from a "reasonable" loading with powder as fast as Unique. But I had a fail to ignite using Blue Dot 40 years ago. The slow powders can be trouble if you only utilize one reloading data source. In experimenting with 7mm rem Mag, I found differences of 5 gs for same load from different books. I discontinued my interest in 7 Rem Mag. Start low and increase slowly every time you acquire a new lot of powder., is the common sense rule.

 

[gwpercle]

Get a New up to date reload manual(s) ...I like to have 3 or 4 manuals and use the data to load either old or new Unique .
From my loading I don't see much difference in the burn rate of old and new Unique .
The Data in the New Manuals has better testing ... I don't think the powder has changed that much since the 1970 Speer #8 manual ... the pressure testing has . I simply use the new data to load the older powder after doing some testing ... start low and work up slow to hot loads .
Target and mid-range handgun loads , using New Data , seem to be about the same with new or old Unique ( I still have a big cannister of old Unique that I load with ) I use the new data and see similar results ... I don't know if the new Unique is even that much cleaner ... seems about the same to me .
Gary