Not just for yours Charlie. That’s how it is for every gun. It’s not weight that dictates twist needed, it’s bullet length. And while the norm has been that typically the heavier the bullet, the longer it is, there have been several lighter bullets in a specific caliber, that are longer than their heavier counterparts.

As Charlie mentioned, those Berger 155 Full Bore’s are a perfect example. Very long for for a 155 30cal. So if that is your specimen for example, that answers why. But in the world of firearms, these contraptions do some strange things at times that defy logic. Just something to ponder.