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bluechip
06-21-2016, 10:54 AM
What is the general rule of thumb for powder change as the temp. goes up? Let's say for example I'm using 29.0 grs. of N133 at 65 degrees F and the temp. goes up to 85, how much approximate change and in what direction?

Lee Martin
06-21-2016, 11:24 AM
Generally speaking, as the temperature rises the air becomes less dense. This decreases the time to exit. So to keep the barrel in tune, you slow the bullet by lowering the charge. But that isn't an unwritten law.

Some powders aren't as temperature sensitive. I've been shooting LT-32 for a few years now and as long the air stays dry the gun seems indifferent to temperature. Conversely, as the air gets more moist I'm dialing the measure and playing with seating depths.

-Lee
www.singleactions.com

Wilbur
06-22-2016, 09:38 PM
I don't think it matters...you can't do it right every time.

JerrySharrett
06-22-2016, 10:25 PM
Talking about temperature sensitivity we've been working up loads for a couple of 26 Noslers and around 91 grains 869 powder. That stuff gets real touchy...open the bolt and the primer falls out!


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Lee Martin
06-22-2016, 10:56 PM
Jerry - has US 869 shot well for you? I've used it in my 300 Kong and 50 BMG with good results. I ask because some say it's finicky with respect to accuracy. But again, it runs right alongside Retumbo and 8700 in my guns.

-Lee
www.singleactions.com

JerrySharrett
06-23-2016, 06:57 AM
Jerry - has US 869 shot well for you? I've used it in my 300 Kong and 50 BMG with good results. I ask because some say it's finicky with respect to accuracy. But again, it runs right alongside Retumbo and 8700 in my guns.

-Lee
www.singleactions.com

Lee, so far its working. Just started using these super slow powders recently. Until now 7828 was slow. Use it in a25/264 Win Mag Imp. Long range Kansas deer.

We have had a temp spike here in the last few weeks. Its 74F right now, 5:58 AM...off to the lake. Cooler?? Hope so.


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