prm,
Can I ask what your load of Benchmark with the 180 NAB gave the best accuracy? I couldn't get acceptable accuracy with 180's with either BM 2 ( your Benchmark), or BM 8208.
Both powders give excellent accuracy and on-game performance with 200 grainers - either NAB's or Woodleigh's. With those I'm loading 46.5g of BM 8208 in Fed cases, 210m primers @ 2570f/s.
Average 3 shot groups go into .86" at 100m reliably, with an ES of 24f/s. I could possible get it going a bit faster, but only with highly compressed loads, which I'm not fond of.
I'm planning to hunt with that load later this week, for Sambar and Fallow deer.
Cheers, John