The reason the "data" from both companies is contradictory is because I doubt Ramshot has actually done any pressure-testing with TAC in the .350. If they had, it would be on their website list of loading data. Instead you got it directly from them, and they typically use QuickLoad when they don't have tested data. They are naturally conservative when suggesting QL-generated data, because they've found real-world results often differ some.
I sincerely doubt you're going to get the velocity you're hoping for with the 180 TTSX and TAC, because in the .350 TAC is essentially a very slow-burning, high-volume powder, and you won't be able to get enough in the case. No doubt that's why Barnes doesn't list any TAC data for the 180: The max load they list for 200's, 64.0 grains, is about all that can be stuffed in the .350 case and still seat a bullet.
In my own tests TAC worked well in the .350 with 225 TSX's and 250 Nosler Partitions, but in my rifle the Barnes loads for 225's were too much. Instead I stopped at 59.5 grains, instead of the 62.0 listed by Barnes, getting 2700 fps in the 22" barrel of my rifle. No doubt I could have pushed things a little more, but didn't, partly because 2700 seemed like plenty from a 225.
There isn't any 250-grain pressure-tested data, but 57.0 grain got 2440 fps in my rifle with the Partition, and no signs of excessive pressure.
