Not sure about underground, that is what I was told while i was there. I do know they have some sort of controlled range, and i do know it is leased out to Horinday and others. I was there while they were getting cleared at the gate.
Are talking fort AP Hill VA or Aberdeen proving ground Maryland. Two different bases in two different states. I used to work at FAPH and still hunt there and know all the ranges. All thges are controlled. If Crane Labs brought some of the new AI 338s and Hornady ammo, Hornady could have been wtnessing the tests but no way they leased the range. Plus Dave Tooley has been helping with those tests in Doppler radar out in the SW.