Optimum 6.5 Grendel bullet weights

[stanc]

The bare gel test is but one of several tests the FBI requires. IIRC the remainder all have a barrier of sort. A prepared adversary will have better barriers.

Well, if you consider clothing as a significant barrier to rifle bullets, then yes, that "barrier" test should be done. I rather doubt that the performance of a TSX (no matter what weight or caliber) will be noticeably different than the same bullet against bare gel.

The only other barrier likely to be encountered in CQB (against the current enemy, for which the TSX "brown tip" load was created) is a loaded AK mag in a chest pouch. Body armor isn't likely to be worn.

Terminal effects depend on penetration through barriers and flesh. Sectional density is a major factor in penetration depth.

True, but just how much penetration depth do you think is necessary? I've seen nothing to indicate that an 85gr TSX wouldn't have more than enough. The wound cavity of the 120gr 6.5 TSX is substantially inferior to that of the 85gr 6.8 TSX, and the 22+ inches of penetration depth is far more than needed. Or are you planning to get two opponents with one shot?

I'll rephrase the last question in my previous post: Why do you "almost certainly want to at least match, if not exceed, the sectional density of that [70gr 5.56 TSX] bullet"? Is there something vital about that SD?