3" @ 100 is a decent group but if you're hunting deer with a 10" kill zone then a 5" group would be sufficient @ 100.
That same 3" group would allow you to extend your range to about 150'ish before it starts spreading unacceptably. Conversely the 5" group would have you at your limit at 100 as a 5" group at 50 yd would be your limit.

I guess what I'm saying is your grouping can be quite large depending on your maximum range you plan on shooting and not take the chance on a longer shot unless you know your own and your rifle's capabilities.