Hmmm??? Something doesn't sound quite right.
First, 45 grs of Varget is well of max pressure (like around 66,650 psi)
I just copied this from Dan Newberry's optimal charge weight website. It's for use in Winchester brass and should be reduced by 4% for other brass
.308 Winchester using Varget
155 grain bullet, 47.8 grains
168 grain bullet, 46.0 grains
175 grain bullet, 45.0 grains (an all around favorite)
Personally what works in my old 700 with 24" varmint barrel is 42.5 Varget in Lapua right at 2.800, even though it's jumping something like .130 in my rifle.