Why did changing buffers change my POI?

[montana]

Lol I clean my chamber.

I precision reload.

6.5 Grendel:

123 eld-m MV 2425 SD 9
31.2 cfe 223
Bto 1.658”
Cci 450
Starline brass base to shoulder 1.212” fired cases 1.2165-1.217 (.005” bump)
Trim length 1.510”

Charge master link powder measure

Lots of precision shooters don’t clean their barrels until they stop grouping.

I’m not an amateur, well at least not a noob… just trying to understand what I altered, was it barrel harmonics?

65, changing the buffer weight will not effect POI, it will effect carrier velocity and could have an impact on the ammunition being fed into the chamber.. If the lighter buffer allows the rifle to cycle too fast, damage to the bullet tip, seating the bullet deeper into the case, etc could possibly occur effecting accuracy.. If in doubt, shoot some groups with the light buffer and then with the heavier buffer and compare groups. Easy-peasy..Process of elimination..