TNHagies, The XTP's do preform well with in the enevlope they were designed for,I think most of use agree on that; a few of us have tried to push them beyond that and found out where the limits on a particular bullet are.
A lot of what was said related more to what the minimum that they could go down to depending on which one you are talking about like the 250 is max for best results at 1850, I never found a max on the 300gr. I used the 250 in 4 different rifles with good results but my loads were always under 120gr RS [IF you use a hotter powder like777 or black mag it might be a bit less. The 240 has I believe to different designs one of them is very tough the 230 was designed for low velocity so it does not take much to blow it up. Lee