No, but depending on how true the rings are to 30mm you may need to gently open them up a bit. On all my DS35's the front mount fitted perfectly, but the scope just wouldn't sit comfortably in the rear mount and, if pushed in, it became near impossible to rotate it. I possibly could have tighten the top cap, but it just felt wrong and rather than risk damaging the scope I opted to use a 30mm bar wrapped in thin emery paper to remove some material from the inside the ring. This method only removed material from the upper lips of the mount, but that was enough to allow the scope to sit all the way down and able to be rotated.