Temp stability of TAC and AA 2520?

[Kaldor]

I recently acquired some of both of these powders and need to know a bit more on temp stability of these two. Being that they are ball powders, how temp stable are they? Im planning on loading these in 308 mostly, with a bit of 223 as well.

Ive gotten bit in the butt before with ball powders and doing load dev in cold weather. Everything looks great at 45 degrees, but it hits 70+ and Im popping primers.

 

[Demi-human]

Everything looks great at 45 degrees, but it hits 70+ and Im popping primers.

At least you have a pattern to start with…

I feel as though there should be a chart that has the variance of speed with differing temperature swings with an identical load of powder for many of the more popular powders in .223, but I’ve spent the last thirty minutes trying to find or recall what and where it was. I give up. See you in the morning.

 

[Kaldor]

At least you have a pattern to start with…

I feel as though there should be a chart that has the variance of speed with differing temperature swings with an identical load of powder for many of the more popular powders in .223, but I’ve spent the last thirty minutes trying to find or recall what and where it was. I give up. See you in the morning.

Yup, CFE 223 in 308 with 168s. Shot 3/4", didnt do anything fancy, wasnt incredibly hot. Did that load dev at about 50, went to 80 and it really fell apart
Ive been gun shy since. 8208 is my goto for 308 and 168s, but that stuff is unobtanium

 

[Demi-human]

And this for 2520, specifically for .308 Win.

There. Now I my brain will stop. I think. Unless it doesn’t. Then I will keep thinking.
Pffft. Probably about guns…

 

[Slamfire]

Never been a fan of ball powders for the same reasons you express. They have been peaky, in my experience. If I cut AA2520 enough, it shot well. But loads developed in 70 F weather blew primers in 90 F. It might be due to the fact that ball powders were double based and perhaps the nitroglycerine spikes the pressure curve.

Ball powders are harder to ignite in cold weather. Double based powders have less than half the expected shelf life of single base powders. Nitroglycerine attacks nitrocellulose. From what I was told, the nitroglycerine in the grain migrates to the surface, pulled by water molecules condensing and evaporating on the powder grains. (Humidity is everywhere). A nitroglycerine rich surface will spike the pressure curve.

I am surprised the military went ball powders after WW2. Always wondered why, single based powders have always been more predictable and longer lived.

 

[dcloco]

Which primers are you using?

 

[Kaldor]

View attachment 1060441
And this for 2520, specifically for .308 Win.
View attachment 1060442
There. Now I my brain will stop. I think. Unless it doesn’t. Then I will keep thinking.
Pffft. Probably about guns…

Well it looks like with that first chart, TAC and 2520 are at least both better than CFE 223 by a significant amount. Ill wait until we get some 65 degree weather before I get into load testing this stuff. Besides, i have plenty of other stuff loaded on much more stable powders that I need to work thru first.

Which primers are you using?

CCI 200's. However, the loads I was popping primers on was not a hot load. If I want to go hot, I have BR2s and 250s. Not burning match or magnum primers on AR fodder loads though.

 

[GeoDudeFlorida]

Never been a fan of ball powders for the same reasons you express. They have been peaky, in my experience. If I cut AA2520 enough, it shot well. But loads developed in 70 F weather blew primers in 90 F. It might be due to the fact that ball powders were double based and perhaps the nitroglycerine spikes the pressure curve.

Ball powders are harder to ignite in cold weather. Double based powders have less than half the expected shelf life of single base powders. Nitroglycerine attacks nitrocellulose. From what I was told, the nitroglycerine in the grain migrates to the surface, pulled by water molecules condensing and evaporating on the powder grains. (Humidity is everywhere). A nitroglycerine rich surface will spike the pressure curve.

I am surprised the military went ball powders after WW2. Always wondered why, single based powders have always been more predictable and longer lived.

This might be why the big ammo houses use blended triple-base powders with nitroalkene, dinitrotoluene, nitrotoluene, nitrosodiphenylamine and some form of alkyl or butyl to mitigate the hygroscopic tendencies of nitroglycerine and stabilize the mix. I read a few articles about it way-back-when in these things called "books" - y'all younger folks won't know about them - because I was having some bad reactions hunting in the summer with my usual fall and spring loads. Down here in early February through about mid-April it can be 35F in the morning and 90F before the sun goes down. Kind of like the desert but more gradual. Y'all get this ridiculous freezing at first dark and roasting at first light thing going on. I couldb't do that.

And, because I didn't have my books here and had to googly-do some info, and I always like to cite my sources...
Wissinger, Chad & Mccord, Bruce. (2002). A Gradient Reversed Phase HPLC Procedure for Smokeless Powder Comparison. Journal of Forensic Sciences. 47. 168-174. 10.1520/JFS15219J.

ABSTRACT:
Smokeless powder comparisons are commonly carried out by extracting additives and stabilizer degradation products from the powder using methylene chloride, and analyzing the results by gas chromatography/mass spectrometry. Some of these components are thermally unstable, making comparison of similar powders or of powders originating from different manufacturing lots difficult when GC is used. Isocratic HPLC analysis using C-18 stationary columns can be unsatisfactory due to a wide range of polarities of the additives and stabilizer degradation products and the presence of geometrical isomers. In this paper, a gradient procedure using a C-8 column is described for the analysis of smokeless powders. The procedure provides separation of a wide range of components present in smokeless powders. In this work, analytical figures of merit are provided, UV spectra of each of the components are presented, and the procedure is evaluated by comparing four different lots of smokeless powder from the same manufacturer.

 

[sfl_gunner]

I have questions about TAC myself. I use VVN140 for my precision .223 loads. But I'm running out. I have plenty of TAC tho.

 

[Bearded Phil]

View attachment 1060441
And this for 2520, specifically for .308 Win.
View attachment 1060442
There. Now I my brain will stop. I think. Unless it doesn’t. Then I will keep thinking.
Pffft. Probably about guns…

Can you tell me if I'm understanding this correctly? If there's a blank next to the powder is it considered to be "temp stable" at most temperatures and then if there's a number to the right the powder will either lose or gain that many FPS per degree in F up or down?

Example: IMR 4227- 1.17
So a load developed at 70 degrees that is 1077 FPS would be approximately 1106 FPS at 95 degrees? (25 degree change X 1.17 = 29.25 FPS increase)

 

[Demi-human]

Only the powders with numbers were tested. The blank ones were not. Every powder varies with temperature, some more than others, some inversely.

Example: IMR 4227- 1.17
So a load developed at 70 degrees that is 1077 FPS would be approximately 1106 FPS at 95 degrees? (25 degree change X 1.17 = 29.25 FPS increase)

This is correct.

These tables are just single test results. I used to remember where I first read them, but only the tables were searchable(findable) last night.


Even though CFE223 is quite sensitive, I find it to be a very accurate powder in my comfortable weather shooting. I know in the summer to stay below 26 grains. In the spring and fall 27.2 is the spot. And there is just no beating it’s performance, one just needs to know it intimately.

We got pretty cozy together!

 

[Bearded Phil]

Only the powders with numbers were tested. The blank ones were not. Every powder varies with temperature, some more than others, some inversely.


This is correct.

These tables are just single test results. I used to remember where I first read them, but only the tables were searchable(findable) last night.


Even though CFE223 is quite sensitive, I find it to be a very accurate powder in my comfortable weather shooting. I know in the summer to stay below 26 grains. In the spring and fall 27.2 is the spot. And there is just no beating it’s performance, one just needs to know it intimately.

We got pretty cozy together!

Got it, thanks for clarifying!

 

[Blue68f100]

I read somewhere that some of the RL powders are temp stable but only from < 55F. Another way of saying it's for extreme cold temps. Which explains why I was blowing primers once the temp got to the 80's.

 

[dcloco]

Change primers. Or change powders.

Per Hodgdon.com reloading data center, TAC is 5K psi higher at top load than H4895.

 

[IALoder]

When it comes to temp sensitivity I have found TAC to be pretty well behaved for a ball powder. AA2520 is definitely a bit more temp sensitive, but all in all still not bad. Both experiences in .223 and .308, and upper midrange charges, not on the ragged edge. I really like TAC.

 

[Kaldor]

Only the powders with numbers were tested. The blank ones were not. Every powder varies with temperature, some more than others, some inversely.


This is correct.

These tables are just single test results. I used to remember where I first read them, but only the tables were searchable(findable) last night.


Even though CFE223 is quite sensitive, I find it to be a very accurate powder in my comfortable weather shooting. I know in the summer to stay below 26 grains. In the spring and fall 27.2 is the spot. And there is just no beating it’s performance, one just needs to know it intimately.

We got pretty cozy together!

I dont hate CFE 223, its just that Ive found to get acceptable accuracy with it, you do need to have good case fill percentage which generally brings you towards a max charge. Thats where I got into trouble with popping primers the last time. I was up against that max charge, or close to it, and it was fricking awesome in the cold, but was blowing primers with a 20 degree temp change. Thats why 8208 has long been my standard for 308 with 168s, 223 with 69s and 77s and likely it will be one of the better powders for my 6 Grendel as I test more. It meters well, its fairly stable, and I can get the accuracy and velocity I want with no drama. But I havent seen it available anywhere since spring of 2020 and I need to sit on the last 4# I have left for very specific loadings.

 

[Ru4real]

…but it hits 70+ and Im popping primers.

I throw away all of my spent primers, “popped” or not.

From the tables we can see 0.5% to 5% change in pressure for 125F temp swing, none of which will cause firearm failure. Personally, I’ve found the swing in POI not enough to make a difference, which is what really matters.

The powder makers have it figured out.

 

[Demi-human]

Allow me to be the dissenting opinion.

5% of a 3100fps load is 155fps, enough to move completely out of a node, let alone impact differential from loss or excess of velocity.
Puncturing primers will erode the tip of the firing pin and etch the breech face.
I like them to be cups, instead of sieves, when I de-cap them.

its just that Ive found to get acceptable accuracy with it, you do need to have good case fill percentage which generally brings you towards a max charge.

I, too, have found CFE223 to be sooty and inconsistent at less than “full”. Which is why I run it so hot, and have different charges for the weather. It’s the H-110 of rifle powders, it doesn’t reduce well, but nothing beats its performance.
If Varget is the F-1 of rifle powders, CFE223 is the methanol blown drag car.


One thing I find interesting, and experienced just the other week. Ramshot Silhouette is inverse temperature sensitive. I loaded up some plinking rounds for my 1911, took them out to the frozen woods and used them. Much to my surprise, they were quite warm! I could tell the report and recoil was greater. And they shot beautifully. When is gets warmer I’ll have to try some +P loads to make up for the lack of cold.

I just recently looked about at all this temperature sensitivity stuff because of it. That’s why I remembered-ish the chart.

 

[Kaldor]

Allow me to be the dissenting opinion.

5% of a 3100fps load is 155fps, enough to move completely out of a node, let alone impact differential from loss or excess of velocity.
Puncturing primers will erode the tip of the firing pin and etch the breech face.
I like them to be cups, instead of sieves, when I de-cap them.


I, too, have found CFE223 to be sooty and inconsistent at less than “full”. Which is why I run it so hot, and have different charges for the weather. It’s the H-110 of rifle powders, it doesn’t reduce well, but nothing beats its performance.
If Varget is the F-1 of rifle powders, CFE223 is the methanol blown drag car.


One thing I find interesting, and experienced just the other week. Ramshot Silhouette is inverse temperature sensitive. I loaded up some plinking rounds for my 1911, took them out to the frozen woods and used them. Much to my surprise, they were quite warm! I could tell the report and recoil was greater. And they shot beautifully. When is gets warmer I’ll have to try some +P loads to make up for the lack of cold.

I just recently looked about at all this temperature sensitivity stuff because of it. That’s why I remembered-ish the chart.

Great analogy and that is exactly what Ive found as well. Im pretty sure it has more to do with load density due being a ball powder, you can get alot more in the case without any effort.
Varget, H4895, 8202 XBR, Benchmark, H4350, all boringly predictable. I just figure just shy of a compressed load with these, and you will be damn close to a perfect load, and are my 5 go to powders. CFE 223, well, you better be on top of it.

My personal favorite for high velocity pistol loads is CFE Pistol. Im shooting my 45 with 185 HiTek coated SWCs at close to 1150fps and they are like a laser and hit that steel with some authority. Im seeing no case or primer issues that I would worry about, and no unusual wear on my 1911. I could probably push another 50fps out of it, but Im really happy with what I have. My buddy looked at me like I was crazy until he shot a handful from his 1911, and then asked what was that load?

 

[Jerry M]

I got more vertical dispersion with AA2520 then H4895 at 600 yards with my .308 Win.

 

[FROGO207]

TAC is better with the mid to heavier bullets in both 223 and 308. This is my main 223 propellant with 60 to 75 grain bullets. It seems fairly temp stable unless below 30 degrees for me.

 

[sfl_gunner]

Anybody have experience with TAC with heavy bullets for .223 in the summer.

 

[IALoder]

TAC is better with the mid to heavier bullets in both 223 and 308. This is my main 223 propellant with 60 to 75 grain bullets. It seems fairly temp stable unless below 30 degrees for me.

Pretty much my experience with TAC as well.

 

[Blue68f100]

Anybody have experience with TAC with heavy bullets for .223 in the summer.

The heaviest I've used is 69gr SMK in my 223R. AR. Once of my more accurate loads.