The Speer 180gn BTSP with 63 grains of H414 produced the most consistent accurate loads out of my Nosler 48 Custom Sporter when I developed the load, as long as it was between -10 and - 25 degrees Celsius. The muzzle velocity was 2940 fps +/- 7 fps. When the temperatures warmed up to above 0 the groups opened up a huge amount from .5" to 1.5" or worse. The H414 is temperature sensitive and this really showed.
I switched to Nosler 180 Accubonds with 63gn of H4350. The muzzle velocity was a bit lower at 2900fps and the groups only slightly bigger on average, but they were more consistent at warmer temperatures. The H4350 is supposed to be more temperature stable over a broad range of temperatures. This is more important to me than raw accuracy or speed. The load still groups in the 1/2" range (a little more or less) for three shots with the first two shots usually touching.
The Speer bullet did not shoot as well with H4350 as the 180 accubonds did but I like the accubonds better anyway.
The first image below is the 180gn Nosler accubond using H4530 and the second picture is the Speer 180 BTSP using the H414.
In regards to using the Hornady SST - I am not a big fan. I used it in a Tikka T3 270 win for one season. It was accurate and fast at the range. I let a friend use the rifle on a small whitetail buck. He took a very well placed quartering shot that hit the back rib, disintegrated in the vitals and left only fragments in the far, front shoulder. The animal ran a few steps and then dropped. It worked. The only problem was that the entrance hole was larger than any exit hole I had ever seen. It had exploded on a rib entering the animal and the bullet didn't exit the far shoulder. Despite not exiting, the shoulder was so badly shot up with fragments that it looked as if someone took a shotgun to it from the inside. The meat was unusable. I am mostly a meat hunter and after I saw that I was not interested in the damage that it would do to the meat of the animal. I wasn't even sure if it would make it through shoulder or leg bone if encounter entering an animal. I switched to the Accubonds again and only gave up a slight amount of accuracy for much better bullet performance and less meat damage. I know, it is all about bullet placement to avoid meat damage but at 200 yards a little wind, a touch of adrenaline, a quicker heart rate and a rushed shot can easily move a bullet up or down and left and right a few inches so that you risk hitting thicker bone and not just flesh. I certainly would have reservations about using it in the 300 WSM. It is fair to say that the Speer BTSP may not perform that much better, being a softer cup and core bullet, but I have never used it on game before so I have no experience and am welling to give it a try. Because the accubond shoots I don't have to.
I have to admit that I really like the Nosler Accubonds. I've shot moose out to 400+ yards and deer at 50 yards and the performance and accuracy has been very good. Animals don't usually drop in their tracks, unless I am aiming for the neck, but it leaves a reasonable sized exit wound and blood trail and it has always made it through the animal without damaging more meat than necessary to get the job done. I have shot at least 40 animals with it in three different calibers and have not been disappointed. I find it easier to hand load for than most other bullets as well. I try lots of different types of bullets but it usually comes out on top, but not always. It may not have the consistent accuracy of a Berger or Sierra Match King but I know it will make it through the animal more reliably.
