Author: britrifles
Subject: Velocity change due to Ambient temperature.
Posted: January 21 2025 at 1:53am
Norma 202 is a double base stick powder, so expect on the order of 1 fps per deg F.
Subject: Velocity change due to Ambient temperature.
Posted: January 21 2025 at 1:53am
Norma 202 is a double base stick powder, so expect on the order of 1 fps per deg F.
I doubt the muzzle velocity will change that much from what you chronographed, and if you already have a 200 yd zero with this load, your GTG.
I’ve never noticed a change of 200 yard zeroes here in GA shooting from say 30 deg to 85 deg. At 300x and beyond, I’ve seen some change when using double based ball powders of about 1 to 2 MOA.
As I have found, the primer can make a substantial velocity change, so you may be experiencing a combination of factors that are reducing the velocity to below what the load data shows.
Good luck at the match!