Temperature Stability: Is there an official standard?

[Tommie]

Most of us have seen charts showing relative temperature stability of various powders. Some powders are more stable than others. Appears the measurement is FPS change per degree of temperature. Great. My question regards the actual definition of the term. Is there any established standard (by SAAMI, CIP or other body) which determines at what point a powder can be declared or marketed as "temp stable"? It seems there are very temp stable powders, somewhat stable and barely stable.

Is there an official standard for temperature stability? If so, by whom?

Thanks in advance.

 

[BoydAllen]

I am not aware of any standard.

 

[urbanrifleman]

To me, Alliant Bofors TS powders are the standard.

 

[RegionRat]

My question regards the actual definition of the term. Is there any established standard (by SAAMI, CIP or other body) which determines at what point a powder can be declared or marketed as "temp stable"?

No SAAMI or CIP standard for the propellants being called "temp stable" that I know of.

Now just an opinion... you would never get a powder/ammo company to agree to one since the chemistry doesn't exist. If someday one of them can pull this off, then they would play the advantage all the way to the bank.

Merry Christmas, Happy Hannukah and Happy New Year!!!

 

[JEFFPPC]

There is only one way to know for real. Leave your gun and ammo reach ambient temperature at say 85 degrees. Next winter at say 30 degrees allow gun and ammo to reach ambient temperature. Compare velocity. That will tell you the truth. Reading the can or advertising or watching a video with ammo in the freezer being shot out of a gun at s ambient temp of 72 degrees may/will not tell you the truth.

 

[Fuj]

You can bet, the military has a mil standard. When I was in artillery
school, part of the plot was temperature pertaining to the charge
bags......Any recent 13B MOS members ?? Just for the exercise......
current 155mm charge bags come with a thermometer installed in
each bag. Before the gun is loaded, that bags current temp is entered
into the computer as part of the plot. Cold powder, you will be short.
For personal rifle shooting, you still have to develop your own standard.

 

[KMW 1954]

So what constitutes the parameters to determine a powders stability? Does it have to be stable at all temps? Can there be predetermined ranges, say high temps vs. low temps?

 

[urbanrifleman]

There is only one way to know for real. Leave your gun and ammo reach ambient temperature at say 85 degrees. Next winter at say 30 degrees allow gun and ammo to reach ambient temperature. Compare velocity. That will tell you the truth. Reading the can or advertising or watching a video with ammo in the freezer being shot out of a gun at s ambient temp of 72 degrees may/will not tell you the truth.

Before you go to the range. Take three rounds each and put them in a sandwich bag.

Put one three round baggie in an ice bath.
Put one wrapped in a towel with a hand warmer packet.
Put one left to set out in your house and then your vehicle on the way to the range.

Shoot all over the chrony.

Shoot the three ambient.
Then cold.
Then hot.

There's your test.

 

[JEFFPPC]

Before you go to the range. Take three rounds each and put them in a sandwich bag.

Put one three round baggie in an ice bath.
Put one wrapped in a towel with a hand warmer packet.
Put one left to set out in your house and then your vehicle on the way to the range.

Shoot all over the chrony.

Shoot the three ambient.
Then cold.
Then hot.

There's your test.

I disagree.

 

[drop_point]

When its extremely hot outside, we can make sure not to let our rounds "cook" in the chamber by not chambering until we are ready to fire. When it is extremely cold outside, we can cook the rounds by chambering as we ready to fire. The temp of the ammo, the temp of the barrel, and the temp of the air all affect what happens with our velocity.

Using Varget, I shot the same load at 90 degrees then again at 35 degrees and the change in velocity was about 10 fps in a 30" barrel .308 Win.

I don't think there is a standard for defining it nor is there a standard for any single powder because it is so nuanced.

 

[Fuj]

Using Varget, I shot the same load at 90 degrees then again at 35 degrees and the change in velocity was about 10 fps in a 30" barrel .308 Win.

Did you actually have those cartridges at those temps ?? When Shooters
World (Lovex) Precision rifle came out, it was said to be real close to Varget,
and Varget was hard hard to find. I put 5 of each in the freezer, in the
range house, then did all my normal set ups, and fired over the Lab Radar,
5 of each of Varget and Lovex. Those rounds I had sitting in the sun with
outside temps at 80 degrees. Probably sat there for an hour. I wish I had
my temp gun which I normally have to check barrel heat as I fire form. Either
way, The Lovex and Varget did shoot real close to each other. The cold ones
were a different story. Varget's average over 5 shots dropped 14 fps with the
group doubling in size, where the Lovex dropped even lower to an average
of 21 fps, with the groups also doubling in size but still close to Varget.......
It just satisfied me that the Lovex was a good replacement when Varget
disappears again, however, Lovex pulled the same disappearing act. I miss
the fact that Lovex at the time was $12 bucks cheaper per lb.

 

[miningshawn]

PV = nrT. There is a reason T is in there...

 

[drop_point]

Did you actually have those cartridges at those temps ?? When Shooters
World (Lovex) Precision rifle came out, it was said to be real close to Varget,
and Varget was hard hard to find. I put 5 of each in the freezer, in the
range house, then did all my normal set ups, and fired over the Lab Radar,
5 of each of Varget and Lovex. Those rounds I had sitting in the sun with
outside temps at 80 degrees. Probably sat there for an hour. I wish I had
my temp gun which I normally have to check barrel heat as I fire form. Either
way, The Lovex and Varget did shoot real close to each other. The cold ones
were a different story. Varget's average over 5 shots dropped 14 fps with the
group doubling in size, where the Lovex dropped even lower to an average
of 21 fps, with the groups also doubling in size but still close to Varget.......
It just satisfied me that the Lovex was a good replacement when Varget
disappears again, however, Lovex pulled the same disappearing act. I miss
the fact that Lovex at the time was $12 bucks cheaper per lb.

I didn't play any games. I just took them out and shot them just as I would in any other match.

 

[Krogen]

PV = nrT. There is a reason T is in there...

That's the ideal gas law and completely irrelevant to propellants generating gases in combustion.

 

[jelenko]

Personally, the OP's question has been thoroughly examined and answered.

 

[KMW 1954]

So the last few responses sort of address my question. How large of a temperature change does there need to be to effect a noticeable change. 20*, 50*, 80*?

This concerns me as for the next 11 weeks I will be shooting in a local rifle league and during that time we can experience ambient temp swings of about 50*. Temps ranging from around 40* -10*..

The past 3 years I had been shooting a 223 using Benchmark and A2460 powders and never noticed a real difference in POI or group size. Now this year I will be shooting a 6ARC using Lever which I have been told is temp sensitive. Yet I worked up these loads over a temp span of 20* - *40 degrees and they appear to be stable and have one session shot at 10*, again same results.

 

[okie]

Before you go to the range. Take three rounds each and put them in a sandwich bag.

Put one three round baggie in an ice bath.
Put one wrapped in a towel with a hand warmer packet.
Put one left to set out in your house and then your vehicle on the way to the range.

Shoot all over the chrony.

Shoot the three ambient.
Then cold.
Then hot.

There's your test.

This!

 

[Tommie]

Personally, the OP's question has been thoroughly examined and answered.

I’m the OP. The original question (which predictably derailed) really is a “yes” or “no” proposition.

So is the answer “no”?

 

[DiffEQ]

Does anyone have a link to a comprehensive list of velocity/temperature values for all the different powders?

 

[urbanrifleman]

Did you actually have those cartridges at those temps ?? When Shooters
World (Lovex) Precision rifle came out, it was said to be real close to Varget,
and Varget was hard hard to find. I put 5 of each in the freezer, in the
range house, then did all my normal set ups, and fired over the Lab Radar,
5 of each of Varget and Lovex. Those rounds I had sitting in the sun with
outside temps at 80 degrees. Probably sat there for an hour. I wish I had
my temp gun which I normally have to check barrel heat as I fire form. Either
way, The Lovex and Varget did shoot real close to each other. The cold ones
were a different story. Varget's average over 5 shots dropped 14 fps with the
group doubling in size, where the Lovex dropped even lower to an average
of 21 fps, with the groups also doubling in size but still close to Varget.......
It just satisfied me that the Lovex was a good replacement when Varget
disappears again, however, Lovex pulled the same disappearing act. I miss
the fact that Lovex at the time was $12 bucks cheaper per lb.

One FPS per degree f is really quite outstanding. There are some powders like reloader 15 that are closer to 8 or 10 FPS per f degree.