I tried 3FGOEX, but not a lot of loads in my .50. It prefers 2F GOEX. This had happened with my .50's, every one of them since 1972/3.
These loads gave almost exactly the same point of impact. The 2F was a mite more accurate. This is not to say there is no load of 3F that
won't beat the 2F load. This was just a couple "chosen" loads. The take-a-way from this, so far, is obvious.
Actually, I haven't taken the time to work up a load - yet. It's a Rice gun-maker's barrel. I don't know what the ROT is.
Shot with this rifle.
Here is the original owner of that rifle, Leather Belly, RIP brother - you are remembered and held close.