Flatwoods Outfitters Gun Shop and Range in Hubert (near Swansboro) is where I would go - went to a friendly match there a few years ago and was impressed with the staff.
Lived in Havelock/Cherry Point from 1959 until 1972, Dad was XO and chief test pilot of what was then called NARF (Naval Air Rework Facility, now NavDep) on base. I don't go back all that often but will be in the area this weekend (October 8th) for a funeral. My guess is that Havelock will dry up and blow away when the Hwy 70s bypass is finished and nothing of value will be lost.
Back before 9/11, the Rifle Range Detachment (now part of Weapons Battalion) at Stone Bay, Camp Lejeune, used to welcome civilian teams once a month for Saturday matches with the various teams on base. They were pretty casual about "teams" and we often made up a team on the spot with whoever showed up. As a bonus, you could volunteer to police the range after the match and keep the brass. An extra bonus was when former match armorer Sgt. Charlie Lauer (Ret) would come by with his mobile shop and do trigger jobs and such. Them was the days.