I want to try and work up a load for my ML using some new bullets and powder. I finally have a day off tomorrow. How much difference does it make if it is 32oF or 50oF?

I would say it does'nt make any difference. I shoot when it's zero out and when it's in the 60's, I never notice any differnece in accuracy. But the temperature of the barrel will cause accuracy to suffer, the hotter the barrle the worse it gets. Now some will notice that when shooting while it's cold out the accuracy is good and others will say when it's hot out it suffers. I think it's mostly because when it's cold out and your shooting the cold helps the barrel cool faster and when it's hot out the barrel takes longer to cool off.
(BP)

I just ran the numbers through a ballistics calculator.

I got 7 fps difference, and no difference in POI.

I admit that the biggest concern with temperatures is when you over heat the barrel. As long as you are shooting and the barrel has a chance to rest, it should make very little difference.

thanks for the info/replies, I will give it a try and see what happens

Cayugad,
I know you shoot alot. Can you explain more about what you mean by letting the barrel rest?

Thanks,
HOOSIER

Actually it is not so much the temperature of the barrel as what it does to the plastic sabots, when the temperature of the barrel is high enough to soften the sabot your results will change. I live in AR and some times in the summer shoot in over 100 degrees so I take 3 or 4 muzzle loaders and shoot them one at a time and let the first cool while shooting the others. The only other way to maintain accuracy in that kind of temperature is to artificially cool and that brings on two other sets of problems.

What (cayugad) meant by letting the barrel (rest) is when your shooting the barrel will get warm or even hot sometimes, you should let it rest (cool down) inbetween shots.
(BP)