It wouldn't be too compressed with 225 Partitions, but TSX's and maybe even the Sierra GK might be a problem. Compression really doesn't hurt anything with extruded powders, but one reason TAC works so well in the .258 is it's a spherical powder, so is much denser than IMR4895 or RL-15. It doesn't compress much at all with the 225 Partition, which is what I load most in the .358.
TAC also happens to be reasonably available right now. I just had an 8-pounder show up via FedEx at my front door about an hour ago, and saw it in two stores yesterday.
