40 by 100 is correct, indoor classroom for traveling instructors and a bunkhouse with kitchen, but range is outdoors. But hey, now ya got me thinking about a long narrow indoor? I just hate to give up one sq in of shop space. That is some seriously high value space!
Go underground for the range. Long trench with a roof over it and low side lights. Roof height only 6’ above grade with 18” side wall and windows. You have the acreage.