Lead-Free Bullets and High RPM Question

[Franko]

Does anyone have experience running something like a Barnes Varmint Grenade or Nosler Lead-Free Ballistic Tip at high RPM? I am considering building a 6 GT and it would be nice if it could do double duty as a varmint rifle but I am worried a fast twist (7.5) will spin the relatively light lead-free projectiles apart. Does anyone have experience with running these bullets fast in a fast twist barrel or know how resistant to overspin lead-free projectiles are?

Thanks.