re: I have a ballistic debate that i need help with....

The .270 Winchester was designed around a .130 grain bullet.

Many years later, the .270 WSSM was also designed to shoot a 130 grain bullet.

I own and shoot both calibers. I am a huge proponent of the idea that confidence in your gun and ability to shoot is far more important and correlates very strongly with accuracy and lethality afield. My confidence increases based on my ability to shoot extremely tight groups under controlled conditions (bench shooting). My experiences with both calibers is that I have been able to consistently get less than 1/2 inch, 5 shot groups at 100 yards with 130 grain bullets, almost regardless of the bullet shape (NBT, BARNES X, etc). On the other hand, both guns and calibers tend to be much more sensitive to the bullet shape or style when shooting .150 grain bullets, and I have a much more difficult time getting the same sub .5" groups with them. FWIW, just thought it might give you a different perspective.