Sierra,in the last couple years,came out with a new 155 gr Palma.It is now called the Palma.It has a BC of around .500.For me,in the AR,loaded mag length,accuracy was mediocre.That is no reflection on the bullet.It may shoot very well in your bolt rifle with over all length tuning.
The 155 gr bullet that was the Palma bullet ,previous generation,has less of a BC.IIRC,its about a .450.(advertised).Now it is called the 155 Matchking.
That bullet shoots very well from the two AR's I tried it in.
In comparing velocities between gas and bolt guns,the gas port costs velocity.All other things equal,you may approach 100 fps more velocity in a bolt gun.