Do you guys notice a big difference in powder performance between hot days and cold days? I ask this because I just worked up a good load for my 22-250 using H380. It's been pretty cold here while I did all this work, so will my groups go crazy once it's 90 degrees out and I'm taking aim at a groundhog 300yds out? I'm also interested in what you guys have seen with other popular powders.

[QUOTE]Originally posted by jethro:
[qb]Do you guys notice a big difference in powder performance between hot days and cold days?

Yes there will be a difference.

If you are loading hunting loads and use the mfgs. specs and following good loading proedures to check all loads for performance and pressure signs you should be fine. If you load out on the edge of the performance scale for a given cartridge then you may have a problem going from winter to summer temps. I load all kinds of powder,but mostly surplus ball for cost savings.
I have never had a problem(since 1964)using loads in the mfg performance range for a given load with ball powder,but remember,I load hunting and practice loads and do not load out on the edge of performance for a given cartridge. If using non-canister powder remember to work the load up carefully to make sure the powder is in the intended pressure range specs.
Best , Dyno

[ 03-09-2003, 20:44: Message edited by: Dyno ]

I'm well within the Max/min range, so there are no concerns there. I'm more concerned about how it will effect my groups. I'm shooting .4's now. Can I expect it to open up?

You may need to wait and see just how it performs at 9o degree conditions.I would chrono the load you are using at the cold temp and follow by checking again as temps rise. H380 is a good choice for the 22-250.

Best,Dyno