I recommend a AR-10 for everyone. 7.62 (.380) will do the job.
AR-10s are chambered for 9mm Kurtz (short)? :)
I do believe you meant .308. :)
Pshaw. If you want a REAL .308 get one of each of these.
Springfield SOCOMII
Springfield M25 "White Feather"
Or the really badass H&K PSG1