OAL and different powders?

In a word, maybe, for common shooting, going by a rounds book OAL will be fine, but when switching powders, or making any other load change, you should back off on the powder charge, by 10 to 15% below book max charge, as with any change to your reloading practice.
If your reloading practice is more advanced, to improve accuracy etc, and you have considered moving the bullet forward or closer to the lands, you should use a measuring tool like the Hornady (old Stony Point tool) bullet comparator, witch will give you a reading from the barring point (or Datum point) of a bullet to your lands, as this is what counts. This is also a much more accurate way to measure a Jump or Jam, as the bullets OAL will vary as much as .010"+.
I dont want to go any deeper, as I dont know what your lever of reloading knowledge and experience is, if your new to reloading, go slow, ask questions and read all you can find. And this is a great place to find the answers.
Mike.