I used to live in Maryland, and I frequently shot at Clark Bros., but it's been awhile since I last shot there. Unless they've changed the range configuration, max target range is limited to 100 yds.
As ECS states in the previos post, Clark Bros. compels you to purchase "their ammo" ... meaning factory ammo (or boxed reloads) that they sell in the store there (at heinously marked-up prices). They used to use flourescent orange price tags on the ammo boxes to enable easy identification of "their ammo" by the RSOs. They'll kick you off the range if you didn't buy the ammo in their store. If you go decide to shoot there on a regular basis, I suggest that you save their ammo boxes (with the price tags) and refill them with ammo you purchased somewhere else at a more reasonable price (or reloaded yourself), so that you don't have to suffer getting bent over on the price of "their ammo".