I remember reading about this a few years ago... the MC4700 "super-fuze"
It looks like it was deployed back in 2009 on the warheads on Trident SLBMs. From [0]:
"Before the invention of this new fuzing mechanism, even the most accurate ballistic missile warheads might not detonate close enough to targets hardened against nuclear attack to destroy them. But the new super-fuze is designed to destroy fixed targets by detonating above and around a target in a much more effective way. Warheads that would otherwise overfly a target and land too far away will now, because of the new fuzing system, detonate above the target.
The result of this fuzing scheme is a significant increase in the probability that a warhead will explode close enough to destroy the target even though the accuracy of the missile-warhead system has itself not improved.
As a consequence, the US submarine force today is much more capable than it was previously against hardened targets such as Russian ICBM silos. A decade ago, only about 20 percent of US submarine warheads had hard-target kill capability; today they all do."
More accurate warheads also means smaller warheads. The goal of the warhead is to take out the intended target. If you can't do that with precision, you brute force it raw power. As they say: "There's only 'close' with horseshoes, hand grenades, and nuclear weapons".
But even that's not true. The hardened targets are designed to be hardened against the capability of the potential attacker, that whole arms race thing.
We dropped vast tonnage of dumb bombs in WWII simply because we had to contend with a) getting the bombers through in the first place, and b) ensuring the designated target was effectively damaged.
Replace a fleet of B-17s with a B-2 and some precision munitions, and you get a net win of effectiveness.
Same with nuclear weapons. When you can miss by a country mile, you need a warhead sized so that it doesn't really matter. Better precision in guidance and fuzing is a "good" thing.
The dark side, smaller weapons, potentially, are "more usable" with "fewer side affects" (which is also a "good" and "bad" thing).
It looks like it was deployed back in 2009 on the warheads on Trident SLBMs. From [0]:
"Before the invention of this new fuzing mechanism, even the most accurate ballistic missile warheads might not detonate close enough to targets hardened against nuclear attack to destroy them. But the new super-fuze is designed to destroy fixed targets by detonating above and around a target in a much more effective way. Warheads that would otherwise overfly a target and land too far away will now, because of the new fuzing system, detonate above the target.
The result of this fuzing scheme is a significant increase in the probability that a warhead will explode close enough to destroy the target even though the accuracy of the missile-warhead system has itself not improved.
As a consequence, the US submarine force today is much more capable than it was previously against hardened targets such as Russian ICBM silos. A decade ago, only about 20 percent of US submarine warheads had hard-target kill capability; today they all do."
[0] https://thebulletin.org/2017/03/how-us-nuclear-force-moderni...