This is a piece of information that I like to know too. I live in southern California and there is not much temperature variation here. I like to know what will happen if I load something here and then shoot it in a cold snowy climate.. In some calibers, I have noticed that a particular load +- 1 grain shoot very good groups. In this case, it could be wise to choose the high side of the load so in cold climate the load still performs as if there 1 or 2 grains less powder and still will shoot well. I have not put this "theory" to test though..

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Going back to the topic of loading N-570 in 7mm Mag, I did load a series of loads in 7mm Mag using Norma 217 which is very slow burning powder in the same "class" as N570. The results are shown in the plot below. I believe these N217 loads that I tested potentially exceed the safe pressure margins so I do not recommend using them. I intend to test Norma 217 again but with a few grain less charge..


[Linked Image]

Last edited by Omid; 05/17/17.