Lately I've been playing with Lt-32, Tac, Benchmark, IMR-8208, IMR4895, CFE223, H322, W748, H335, and BLC-2 with 50-64gr bullets.
So far the leaders with light bullets are LT-32 and TAC. With the 60-64's it IMR4895. H335 deserves an honorable mention. It's turned in some good groups with 52gr bullets, but has not performed well with either the 60gr partitions nor the 64gr BSB's.