The longer, not heavier, the bullet is the faster the barrel twist needs to be to properly stabilize it.

For example........ a round nose lead bullet of "X" weightwill need "Z" twist rate, say 1-14,to be properly stabilized. A pointed, boat tail, lead nosed bullet of equal weight is signifigantly longer than the round nose bullet and will need a slightly faster twist of maybe 1-12, and an all copper, pointed, boat tailbullet of the same weight is even longer and will need a faster twist still of maybe 1-10.