| 450_366 |
| (.400 member) |
| 10/10/12 09:19 AM |
|
Re: Powder Temperature debate
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Quote:Quote:
The stabilizers in modern powders do deteriorate when subjected to heat.
But it takes at least 1,5-4 year (depending on the concentrate of NG) in 65 degree celcius to get it to a point where it start to effect the powder.
So its possible, but it will be a wery long and sweaty hunt.
450_366?
What about powders without nitroglycerin, ie: the single base stick powders made from nitrocellulose only? The double base powders are made from nitrocellulose plus nitroglycerine in varying amounts, I believe.
None of the ball or spherical powders sold by Hodgon are listed as being "Extreme". My own findings are that in -20C temps, rounds from 7X57 through '06 and .375's, when using ball or spherical powders, you can expect up to 150fps reduction is speed from a load developed in 70F temps. Then again, using ball powder, I noticed a drop of a good 175fps in my .218Bee Ruger #1 when tested at -20C (about -5F). Perhaps ctg. size does not matter as much as ctg. used. In 80F temps, it was an absolute max. load.
SB powders would land at about 2,5-3 years time, but thats aging of the powder.
I don think its if its a SB or DB powder thats the problem. A SB powder is less vulnerable to lower temeratures than the DB powders, a DB can actually produce higher pressures in extreme low temperature.
But all are affected by heat as the flame travels faster in higher temperatures. But if i remember right then about 1m/s and 1MPa to every degree celcius is a normal diffence.
So if you developed the load with -20c components and carried it in a pocket that say was 40c, it would add around 60ms and 60Mpa on the load.
Nevertheless, i dont think the pockets are hotter then the blued barrels if its used in hot climate anyway.