temp sensitive powder

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broncoguy72

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I have heard about this but I don't know how much difference it makes on acceracy. Maybe I'm just tring to find a reason I can't hit coyotes lately but I may help me make a choice of powder's easier. Any info would be great. Thanks.
 
In my 204 Ruger I did some tests 2 winters ago with my rounds I had zeroed at +20c. When It got down to -35C my POI would move 1 3/4" at 100yds. These where rounds loaded with BL-C(2) and since then I have changed to H4895 and had no problems.
 
B-78 said:
In my 204 Ruger I did some tests 2 winters ago with my rounds I had zeroed at +20c. When It got down to -35C my POI would move 1 3/4" at 100yds. These where rounds loaded with BL-C(2) and since then I have changed to H4895 and had no problems.
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I noticed something similar with IMR 4895 in my 22-250. I developed a load at -5 degrees and was getting under an inch groups. at +20 they would open up to almost 2 inches and would shoot a bit high.
 
I use a chrony, and even with the Hodgdon Extreme powders, I still notice quite a difference. In the summer shooting at +15/+20 the loads were very hot. Slight pressure signs and very fast velocities. Shooting last week at -20, and the loads were 200 fps slower and no pressure signs at all. The powder that showed the least difference was Winchester Supreme 780 in my 7mmWSM. The one that showed the most was H380 in my 6.5x55. My 280 and my 30-06 were both loaded with H4350, and they suffered a drop of about 100-150 fps.
 
Take down the scope settings and then re-adjust for winter. Then use the extreme powders from Hogdon. I've had excellent results with Varget in my .223 and h4350 in my 6.5x55 and 30-06.

-Jason
 
I noticed a difference using RL22 and IMR 4350 in my 7mm mag. Especially between summer of 25 deg and early spring of around -5 deg.

What I do now is that I do all my load development work in the spring whne the temps are about the same as the fall whne I am hunting. Since doing this I have not had any problems.

Another note which I cannot explain for the life of me is that a load worked up and finally sighted in during the springs months will still shoot well in the late summer, but a load worked up in the heat of the summer will not shoot as well in the colder weather ??

Anyone care to enlighten me as to why ??? I have thought it may just be my rifle, a Tikka 695 deluxe ??
 
Yes powder performs differently in different weather, as I have experienced in the past like jacky did.

However there are some powders that are less affected (not affected at all?) by weather. Powders such as Varget and H4895 (very similar powders, that last I heard came from the same plant), like Farlsincharge pointed out, which are noted EXTREME POWDERS

note the logo: sun and snow :)
 
Those of us that have loaded ammo for a long time have been well aware of temperature/velocity variations, and the "Extreme" powders still display these variations, although not quite as much. There have always been powders out there that show less variation than do others. Old Norma 205 [now marketed as MRP] was always relatively temperature stable. On the other hand, one powder that lost a lot of velocity when temps dipped down low was W760. I have always adjusted my scopes for the change, and just carried on. Most hunting does not succeed or fail due to 200 fps of bullet velocity, as long as the shooter is aware of it. Regards, Eagleye
 
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I reloaded my .223 mini-14 target and my winchester 100 in .308 Win. with Varget.

Both were affected severely by weather. Now i use H4895, not parfect but much better.
 
Lebauffe said:
I reloaded my .223 mini-14 target and my winchester 100 in .308 Win. with Varget.

Both were affected severely by weather. Now i use H4895, not parfect but much better.
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Strange, I shoot the same load in my F-Class gun -20c - +20c using Varget and it doesn't seem to change the accuracy one bit.
 
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