Thanks for the feedback. I have lobbed lots of lead with the H335, BLC2, and Varget with good results. I've heard lots of good reports but have never tried W748 since my dealer is usually sold out of it. Must be a good sign
I got a good deal on 4# of the Benchmark and wanted to give it a try. I have heard often of the low SD and ES that this powder is capable of. I plan to use it with 69s, 75s and 77s at the 300, 500, and 600 yd marks with a new 25" 1:8 Shilen barrel. The ball powders work great with the 53s at 100 and 200 but in my experience, they just won't keep low SDs and ESs consistently enough for long-range stuff.
Tomorrow morning it will be close to freezing when I shoot and it frequently gets over 110 here. The Hodgdon Extreme powders have given me the best performance across the temp spectrum and only needing to go up or down ~.1 grains of powder to keep the groups in check.