Enlighten me - why can't you run commercial ammo in a Garand?
Most commercial 30-06 is loaded with powder that generates too much port pressure. Proper M1 ammo is loaded to around 2700 fps with powder in the burn rate area of H4895-IMR4064.
This is solvable with an adjustable gas plug -but there are many detractors. Op Rods aren't cheap.
I say get the Garand. M14 mags are not cheap, usually close to $50 a pop.