Truth of the matter is that it depends on where you place the bullet. At 250 yards if shooting for shoulder both Barnes and Nosler Partition will penetrate shoulder bones very well. The mono will probably go through both and possibly exit through a cow’s shoulders. The partition will go deep and fragment leaving the flat base in the other side. The fragmentation of the Partition will typically create a more devastating wound on internals. If shooting for lungs and only soft tissue is encountered, neither is the best choice as both will typically go through at both ends. They will work, but a more frangible bullet will work a lot better in the lungs giving you suitable penetration and the grenade effect by destroying many internal vitals such as the heart, liver, lungs, etc., one example of this would be the Hornady SST with a lung shot, it does create trauma quickly. The 165 grain SST is all I use these days on deer with the 308 Win, its super accurate and fast at around 2,800 fps. The bonded core types like Nosler Accubond and Swift Scirocco are somewhat of a happy medium between the two, plenty tough enough for a cow’s shoulder with enough expansion on lung shots to obtain decent results.
I have used 165 grain Partitions in 308 Win on bull elk with shots in the shoulder and inches lower behind the shoulder. Both Partition and A-Frames give you quite a bit of versatility on game, especially at 250 yards with 308 velocities. Both will expand and penetrate down to 1,600-1,800 fps. The 150 grain load should work fine even loaded slightly down if you wish. That bullet is designed to shed weight and drive the shank deep. It will give you the most versatility when looking at frontal, shoulder or lung shots in my opinion.
To me there really is no such thing as a bad bullet in modern design it’s really understanding the bullet construction, the game animal pursued and the shot placement you wish to utilize to take advantage of the bullet design.
Good luck out there.
