What is Better for long range shooting ? 7mm , 30 06 , or 308?

I wanted to do some friendly long range target practice between me and a friend , im looking at using a either my ruger number 1 with international stock , which I can shoot close to a 1-2 inch group at 100 yards but my dad said if I wanted to I could use his M1A Socom II to practice this week then bring it to the range were we are shooting sat. or his 7mm magnum but Im not sure what he has for a rife I know its set up for long range shooting like the .308 any ideas which would be the best to use prolly shooting at 100 yards 200 yards and maybe more idk