140s with 45.5gr, then 129s with 43gr? That seems like a strange way to get more velocity to me. Isn't it usual to use more powder with lighter projectiles? With the same powder load the lighter projectile should get better velocity, but you arent even at the same load. Generally you should be able to load more powder behind a lighter projectile (less weight, length and bearing surface creating less pressure), though this is not always the case due to differences in projectile construction, design and hardness.
In my 308 I'm currently running 130s with 47gr, 150s with 45gr, and 178s with 42.5gr of 2208. I haven't chronoed it yet but the 130s are going a lot faster than the 178s based on POI at 200m.
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