I am sorry to say that I have not shot my rifle past a couple of hundred yards to date, however that will change this year. I too shoot nothing but 175 SMK's and all my barrels are 1/10. I would rather overspin than under spin. I use a 1/10 Kriegers in all of them even the short 18.5 inch barrels. I use the krieger 1/10 heavy in my garand and shoot 168's out of that one. I plan on trying some 155 this year as Nez says for the short line. I don't really see much of a difference between the 168 and 175's at 200 yards. From what I read the new 155 palma has the same BC as the 168 SMK but due to its lighter weight you get more velocity. I am definitely going to get a box of these to do a little experimenting.
Here is an article from the tech pages at Sierra.
Sierra was selected by the International Palma Committee to design and build a bullet that could be shot in the Palma competition from .308 Winchester rifles out to 1000 yards and remain supersonic. The Sierra Palma bullet is a 155 grain Hollow Point Boat Tail MatchKing bullet. The Palma bullet actually has a ballistic coefficient higher than our .30 caliber 168 gr MatchKing, and, due to its weight can be shot at higher velocities than the 168.
The combination of these two factors allows the Palma bullet to be ballistically superior to the 168 MatchKing bullets at 1000 yards. Palma match rifles usually use a 1x13" twist, however, the Palma can shoot very well with a wide variety of twist rates, including 1x10". The first Sierra Palma's were introduced in 1992, and since then, it has been the bullet selected to be loaded into the ammunition used in the International Palma Team Championships. From 1876 through the present, the highly prestigious championship has gone through many changes while bringing together teams of the finest riflemen in the world. Palma competitors must use iron sights, shoot from the prone position, and utilize a rifle that is chambered for the 7.62 NATO cartridge. The match is shot at 800, 900, and 1000 yards.
The 155 grain Palma bullet will appear in the 4th Edition Sierra Reloading Manuals with updated loading information, due out in January 1996. In the meantime, the loading data for the 150 grain MatchKing in our 3rd Edition Manuals provides an excellent reference for loading.
JBS, I tried using that calculator and each time, it comes up with .7. Is there a trick to using it? I assume I should be placing copper in for the bullet or SG. Thanks for posting it though.
