You found the magic accuracy load for a 165-168 gr bullet in the .30-06. One bullet that shoots very well is the Sierra 165gr HPBT over 46 or 46.6 gr IMR 4064, OAL 3.250.
Even though 4064 has been around for 80 yrs or so, it is an excellent powder, especially in commonly available MILSURPs incl the .30-06, .303., 7.62NATO, 7.62 Russ, 7x57 and 8x57. It even works well in the 5.56/.223, although it is too bulky to throw charges reliably thru a measure. Varget came out around 18 yrs ago and was touted as a much better replacement for 4064. I did a lot of comparative shooting with Varget in a heavy barreled .308 at the time and really didn't find a remarkable difference between it and other old stand-bys in the .308 incl IMR 3031, IMR 4895, IMR 4064, BLC 2 and W748. Probably the best powder in the .308 by a nose was a commercial ball powder from Higginson`s called WC 755. I bought a stash of it and still use it in .308 bolt guns, but I believe it to be too slow burning for a Garand. Varget is a good powder, but is also a bit too slow burning for a Garand.