Depends on how you define "best", but I'm sure a pretty good case can be made for putting these in the top 10, just for starters:
HK PSG-1
Mk 11, Mod 0 SWS (aka M110)(K.A.C. Stoner SR-25 variant)
A good AR15 (Noveske, for example)
A good AK47 (Arsenal, for example)
Mk 15, Mod 0 EBR (M14 variant)
(arguably) Volquartsen Inferno, Fusion, etc.
Mini-14? Idonthinso. It's ok, I guess, for what it is, decent, reliable rifle. But teenage pissin matches ain't worth gettin wrapped around the axle for, obviously.
I cannot really argue with the Garand, if we add a "for its time" clause.
351 Winchester, I like that site; thanks. You got a pic of your Winchester rifle?