.30 Barrel Question

[YEMX]

Supposedly the FX Superior Heavy liner is 1:16 twist.  At least, this is what's listed on Utah Air's website.  Lothar Walther has a .30 airgun barrel, which is also 1:16 twist.  I've been trying to find info on accuracy results for the Heavy liner with heavier .30 slugs...  I'm having a hard time finding them- Could anyone help out with info on the accuracy (or lack thereof) of Heavy liners with heavy slugs (not the hybrids)?  OR, has anyone noted differences between FX's 1:16 and the LW 1:16 barrels?  i.e. lands and grooves, what dia. slugs work best.  I'm worried the LW .30 barrel is more geared towards .308 than a true .30

I'm mulling around another weird idea.