Question Re: R-15 & Temperature

[jimbo1747]

In the last month or so, when temperatures have been in the 50's and 60's, I've worked up an excellent sub-MOA .308 load using Reloader 15. From my understanding, R-15 is not a "extreme powder" and is "temperature sensitive." What exactly does that mean? Are my groups going to open up as the temperature gets warmer or colder?

BTW - I'm not a benchrest or long-range person. I just enjoy doing a little target practice off a bipod at 100 yards.

[ar15barrels]

Your pressure and velocity are going to be higher as the weather warms up.
You can probably keep the groups the same by dropping down the charge weight as needed to keep the same velocity as the weather you developed in.
This could be anywhere from just 1/10 of a grain to maybe a full grain depending on how hot the weather is.

You could see the same effects in the current weather by simply adding more powder to your load.