^truth.
It will vary by rifle.
Same make and model, no 2 just alike.
"If your .308 bolt gun doesn't shoot small groups with IMR 4064, you probably have a gun problem... VARGET has also emerged as a .308 standard, and it works very, very well out to the heaviest bullets. Too slow burning, however, my opinion, for a gas gun (excessive port pressure).
The 4895 "family" ... also performs well in this cartridge with "medium" bullets. ... 4895 is a little faster burning than 4064 and, therefore, produces more suitable port pressure. 4064 is not going to hurt a rifle, but the pressure characteristics of 4895 are well suited to gas guns. If your M14 doesn't shoot well with 4895, you probably have a gun problem. ...
"Real" Palma winners tend to use VARGET, VV N150, or... 4064. ...
This is easy to find, but 42.5gr of IMR 4064 with a Sierra 168 ... "(is a staple).