I was doing some load testing with my 35 Whelen Encore and the NOE 358009 clone (big 280gr RN cast bullet). I was using Unique, Trail Boss, and IMR 3031. The chrono was 10-12 feet in front of the muzzle.
The Unique loads did what I expected (low 1000fps range, mild report and recoil). The lighter Trail Boss load, 14gr, was about like the lighter Unique load (11gr).
But, the 17gr Trail Boss load did something weird on the chrono. The recoil and report felt only a little greater than the 14gr Trail Boss load, but velocity was ~2200fps across 5 shots, nearly double the lighter load! The "wrongness" of that wasn't apparent until I shot the 3031 load (40gr I think, need to check my notes). The 3031 load gave me just over 2000fps, but recoil and report were significantly greater than the other loads, which was expected.
For comparison, the 280gr 2000fps load using 3031 felt close to my hunting load which is a 250gr @ 2400fps load.
So, I either have a "magic" load in 17gr of Trail Boss that gives me high velocity without the associated noise and recoil or something was causing a chrono mistake that was consistent across 5 shots. I *think* the difference in charge weight between 17gr of Trail Boss and 40ish grains of 3031 may have been part of it. The weight of a powder charge does impact felt recoil and 40gr is quite a bit heavier than 17gr, but I wouldn't have expected that much difference.
As far as accuracy is concerned, none of them were great, though the 11gr Unique load showed promise. Some tweaks to it (+/- a grain or two and some extra care in casting the bullets) may deliver acceptable 100yd results.
Chris