08-26-2013, 10:59 PM
One of the biggest considerations with the solid bullets like the Barnes TSX/TTSX or Hornady GMX is that your start pressure needs to be accounted for. The solids resist being swedged into the lands of the rifling more than a thin-jacketed cup and core bullet, so they will spike on you much faster with the pressure.
The short story is that you can't extrapolate load data based on bullet weight. Jacket construction, bearing surface length, then weight are the factors to consider. Not only do the solids have more resistance to being forced into the rifling, but they tend to have longer bearing surface for their weight, which increases pressure more quickly.
With the 120gr TSX, you'll notice in the 6.5 Grendel Reloading Handbook that AA's data using BL-C(2) is about the same for the 129gr SST, both showing speeds of under 2500fps from a 24" barrel as mseric pointed out. All it takes is pressure to generate velocity, and an immediate house call from Mr. Murphy.
The short story is that you can't extrapolate load data based on bullet weight. Jacket construction, bearing surface length, then weight are the factors to consider. Not only do the solids have more resistance to being forced into the rifling, but they tend to have longer bearing surface for their weight, which increases pressure more quickly.
With the 120gr TSX, you'll notice in the 6.5 Grendel Reloading Handbook that AA's data using BL-C(2) is about the same for the 129gr SST, both showing speeds of under 2500fps from a 24" barrel as mseric pointed out. All it takes is pressure to generate velocity, and an immediate house call from Mr. Murphy.