RE: How much powder above max do you load with barnes TSX.
For my 257 AI with 100 gr Barnes TS bullets , I ended up at listed max .
This was for accuracy not pressure signs.
Barnes says
In some cases, pressure will be reduced, allowing you to add a couple of grains (in 1/2 grain increments) of powder to the maximum loads listed, while watching carefully for signs of pressure.
Johnch