Started load development on a 6.5 WSM recently. Yes, in the cold! The velocities I'm getting are at least 200 FPS slower than identicle loads I found on Reloaders Nest.com. It was 28*F
when I shot ten loads from 62 grs. Retumbo to 67 grs. in half grain increments. Barrel length is 27". Velocity at 67 grs. was 3058. All were 140 gr. Berger VLDs. How much velocity drop is "normal" from say 70* down to 28*? Am I wasting my time developing a long range varmit load in the winter? I have the next ten loaded from 67.5 grs. to 70.8 grs.,pressure test)but wondering if I should wait for warm weather.
What say ye?
when I shot ten loads from 62 grs. Retumbo to 67 grs. in half grain increments. Barrel length is 27". Velocity at 67 grs. was 3058. All were 140 gr. Berger VLDs. How much velocity drop is "normal" from say 70* down to 28*? Am I wasting my time developing a long range varmit load in the winter? I have the next ten loaded from 67.5 grs. to 70.8 grs.,pressure test)but wondering if I should wait for warm weather.
What say ye?