Aha! RHA this and penetration that! A noted contributor on The Miniatures Page made some excellent points about RHA and its "appeal as 'realistic' data" for wargames:http://theminiaturespage.com/boards/msg.mv?id=75590
By the mid-80s, armor/anti-armor specialists in the intelligence community had all but given up on trying to use RHA equivalency as any sort of meaningful comparison. As Saber6 indicates, the "good stuff" designed to provide protection against both kinetic and chemical energy projectiles had made it a whole different ball game.
Yep, because wargamers "need" something hard and fast to use, wargames rule writers and their tank enthusiasts have some up with data for the games. Doesn't mean the data gives any reflection of reality. I'm quite happy to use very broad categories of offensive and defensive capability, as in GZG's "Dirtside II", since my background leads me to believe that any data generated for wargames is just false detail, as well as to understand that there are other factors involved which no miniatures rules are likely to model.
Your mileage may vary.
"In the early 90s, when I was involved with tank R&D, it was still being used."
Some people still insisted on using it, as telling them "apples and oranges" wasn't acceptable. Doesn't mean the numbers reflected reality; they were produced to keep people happy.
"Some US intelligence captain was court martialled for releasing a pile of figures on NATO RHA equivalents and penetration to Janes Defence Weekly or some other defence periodical."
Exactly, Tim. Anyone who knew what the assessed equivalencies were wouldn't be talking about them. The corollary is that anyone who published them (in a game system) didn't know what they were!
Take for example the T-80. There is a T-80 at Yuma Proving Ground, purchased from the Ukraine. It is still intact. *If* a T-80 had been acquired at any point for destruction testing (the only way to develop credible armor penetration data), anyone who knew about it wouldn't talk about it. If no T-80s had been tested to destruction, there would be no credible penetration data.
Anyone care to reveal information which they know from special access programs? Didn't think so.