temperature sensitive

[1chota]

i use IMR 4985 for .308. i have a friend who uses Varget. he says it is not temperature sensitive. my question is: how sensitive to tempterature changes is IMR 4895? is there enough difference to warrant the change?

[Jammer1911]

It is well worth switching to Varget. I was using IMR4895 for a long time but my zeros were all over the map at different times of the year. Switched to varget and has no trouble since. Not even going to look back. Consistency is awesome. BTW what are you shooting and what is the game. I shoot service rifle with both an M1A and an AR15 (Colt H-Bar and Bushmaster DCM).

I am in Carlsbad.

[bgary]

It is well worth switching to Varget. I was using IMR4895 for a long time but my zeros were all over the map at different times of the year. Switched to varget and has no trouble since. Not even going to look back.

+1 on Varget, but it is worth noting that H4895 (not IMR, but H) is part of the Hodgdon "extreme" powder series as Varget, and has much the same consistency across temperature ranges as Varget.

[g56]

You might find this article interesting:

Pressure Factors: How Temperature, Powder, and Primer Affect Pressure

http://www.shootingsoftware.com/ftp/Pressure%20Factors.pdf

I know this question was on 308, but the following is worth noting:

In Glen Zediker's book "The Competitive AR15" he points out BLC2 for particular attention, unfortunately it isn't a recommendation, in the entire book he only warns against one powder for 223, and that's BLC2, he calls it "spooky under the sun", not exactly a glowing recommendation!

http://fulton-armory.com/thecompetitivear-15byzediker.aspx

Edited July 24, 2011 by g56

[Tom Freeman]

Varget and Benchmark are good choices for big temp swings.

[djeffers]

You might find this article interesting:

Pressure Factors: How Temperature, Powder, and Primer Affect Pressure

http://www.shootingsoftware.com/ftp/Pressure%20Factors.pdf

I know this question was on 308, but the following is worth noting:

In Glen Zediker's book "The Competitive AR15" he points out BLC2 for particular attention, unfortunately it isn't a recommendation, in the entire book he only warns against one powder for 223, and that's BLC2, he calls it "spooky under the sun", not exactly a glowing recommendation!

http://fulton-armory.com/thecompetitivear-15byzediker.aspx

Can you just tell us? I have been using BLC2 in .223 because it was easier to get than Varget. Now you have me curious.

[g56]

There are so many variables it makes it difficult to make generalizations, but from what I have read BLC2 is probably the most temperature sensitive powder available to reloaders.

Hodgdon claims that their H4895 is substantially more temperature stable than IMR4895, personally I find that a bit hard to believe.

Edited July 26, 2011 by g56

[sleepercaprice1]

Be careful with W748 in hot weather if you worked up in cool conditions. I had to keep my ammo in the shade one year when I went prairie dog shooting. I didn't blow any primers, but I definitely had pressure signs when the ammo sat in the sun all day.

[Graham Smith]

+1 on Varget, but it is worth noting that H4895 (not IMR, but H) is part of the Hodgdon "extreme" powder series as Varget, and has much the same consistency across temperature ranges as Varget.

I setup a load in winter (at sea level) using Nosler 155 CC over H4895 and was getting good consistent performance. Later in the year, I went south and up 3000ft and the temps got up into the 90's. There was only a minor change in the velocity, probably due more to altitude than temperature and I was still getting good consistent performance. On the afternoon of the third day, we were up on a hill in a rock quarry and it was 95° and our rifles and ammo were baking in the sun right along with us but performance continued to be outstanding.