Been there a time or 2 (my wife is laughing I'm there at least twice a week, was there all day Saturday and just got back a few minutes ago )
Arlington Fairfax IWLA has a 100 yard outdoor covered rifle and pistol range. Closest target frames are 25 yards. They do not allow drawing from the holster or rapid fire so it is very different from the NRA range.
New member meeting first Saturday of the month. Annual dues is $145, you have a $75 initiation fee and you have to do 6 hours of volunteer time before you can get your range badge.
They also have 4 trap and skeet fields (members pay $2 per round), an indoor archery range, a target archery range, and a field archery range. There is pond stocked with fish and a small camp ground.
Can't forget to mention the indoor air rifle range and some of the finest junior shooters in the nation.
If you want to come out and visit send me a PM. (can't do it this weekend)
Edited to add,
Just read your message again, you were asking about the IWLA in Manassas? I'm talking about the one in Centerville.
"If your plan is for one year, plant rice.
If your plan is for ten years, plant trees.
If your plan is for one hundred years,
educate children." -- Confucius