If you are talking about the older rifles made prior to about 1990 the ADL has a blind magazine. The BDL has a hinged floorplate and a black forend cap. That is it. The metal, sights, triggers, etc were all exactly the same. The BDL sold for a little more. I paid $175 for an ADL in 1975. A BDL at the time was just over $200. I think the BDL's have always had a higher resale value because so many prefer the floorplate.
At some point in the 90's things got more complex. Many of the ADL's were offered with cheaper synthetic stocks and a lower quality metal finish. But Remington made many, many different versions of both. The BDL's were usually better finished, but not always. I've seen some both done in several configurations and often the ADL's are the better gun. The only real difference between the 2 is the floorplate, or lack thereof.
