The Bergers have a secant ojive (VLD, Very low drag) and that makes them longer for the same weight and the ojive makes it harder to touch the lands.
In order to touch the lands you have to seat the bullets out further making the overall length hard to fit in a standard magazine so after market magazines are recommended.
How ever they do not have to be seated close to the lands to get accuracy. In fact Berger states that you can seat as far away as .120 thousandths.
Most have custom chambers cut for the Berger's. But if you do that then you will be limiting your bullet choices and if the rifle does not like the Berger's or other secant ojive bullets you will probably have to have the chamber throat ed.
They are one of the most accurate bullets but the controled expansion on game is of some concern to some people.