I have a accurate load of IMR 4064 I worked up for my 204 and chronoed a month ago at 3800 at around 55 degrees F at about 3500 ft. I did not confirm drop so I am not certain how accurate the fps is. Also, the scope I am using is a leupold Vx 3 with newly installed m1 turrets. Today was super cold at 9 F and around 2500 ft. My zero was set at 100. I went to 500 and shot a solution based on 3800. As expected it was low. Solution called for 6.1 moa. Wind was being mean and 7 to 8 then 3 to 4. Ugh. Well first round was low, 7". Next two confirmed 6 to 7" low. Adjusted to 7.1 moa but went high 4". Running out of light and ammo I adjusted to 6.75 and sent 5 rounds. I pulled 1 and the rest seemed fine. See attached picture. So now that I am thawed out and running the numbers it looks like 3600 is the correct speed to give the right solution at 500. Is it possible to see 200 fps variance in a 45 degree temp swing?