01-27-2013, 06:28 PM
There is 129gr SST data from AA, and several sources of 123gr SMK and 123gr Scenar data in Volume I of the 6.5 Grendel Reloading Handbook, so plenty of good places to run starting loads from. The 123gr SMK & 123gr Scenar tend to have harder jackets and do have longer bearing surfaces, so the 123gr SST can be run a little faster.
We will have a bunch of 123gr AMAX and SST data in Volume II, however Volume I provides a great reference with manufacturer data that has been tested on standardized industry pressure equipment. I'm finding that to be one of the most helpful features to it when looking at powders, bullets, and charge weights where I can see what pressures the max loads are at, and stay under them at an accuracy node.
For example, I just checked in the Hodgdon's portion of the Handbook for any data on 8208 XBR. They have 8208 XBR data for the 90gr Speer TNT, 95gr Hornady V-MAX, 100gr NBT, 107gr SMK, 120gr Barnes TSX, and 123gr SMK.
With the Barnes 120gr TSX, the start load is 25.0gr of 8208 XBR, and max load is 28.0C gr at 2.200" COL with a mv of 2419fps right at 50,000psi from a 20" barrel. The 123gr SMK hits 50,000 psi at 28.5C gr of 8208 with a 2.250" COL, pushing 2497fps.
As I look at Hodgdon's data, I see that they are getting slightly better velocities with H-335, with less chamber pressure. For example, that same 120gr TSX or 123gr SMK can be pushed to the same velocity as with XBR, but with only 48,400psi at the chamber. This is one of the great values of the Handbook, in that we have industry pressure-tested data where we can compare powders right next to each other.
On the other hand, running virtually the same speeds again with the 100gr NBT, H-335 generates more pressure than 8208 XBR.
We will have a bunch of 123gr AMAX and SST data in Volume II, however Volume I provides a great reference with manufacturer data that has been tested on standardized industry pressure equipment. I'm finding that to be one of the most helpful features to it when looking at powders, bullets, and charge weights where I can see what pressures the max loads are at, and stay under them at an accuracy node.
For example, I just checked in the Hodgdon's portion of the Handbook for any data on 8208 XBR. They have 8208 XBR data for the 90gr Speer TNT, 95gr Hornady V-MAX, 100gr NBT, 107gr SMK, 120gr Barnes TSX, and 123gr SMK.
With the Barnes 120gr TSX, the start load is 25.0gr of 8208 XBR, and max load is 28.0C gr at 2.200" COL with a mv of 2419fps right at 50,000psi from a 20" barrel. The 123gr SMK hits 50,000 psi at 28.5C gr of 8208 with a 2.250" COL, pushing 2497fps.
As I look at Hodgdon's data, I see that they are getting slightly better velocities with H-335, with less chamber pressure. For example, that same 120gr TSX or 123gr SMK can be pushed to the same velocity as with XBR, but with only 48,400psi at the chamber. This is one of the great values of the Handbook, in that we have industry pressure-tested data where we can compare powders right next to each other.
On the other hand, running virtually the same speeds again with the 100gr NBT, H-335 generates more pressure than 8208 XBR.