Heh, I remember reading long ago about the switch from KE to HE for anti tank rockets. The allies apparently had decided that KE rockets would be anti-tank and HE rockets would be anti shipping.
As it turns out (and as is mentioned previously), the KE rockets were darned hard to get on target, and only hits counted, whereas a near-miss from a HE rocket could still do some damage.
What was also happening was that the air forces were finding out that the HE rocket wasn't so good at the anti-shipping role either, since short rounds just blew up on hitting the water and didn't damage anything. Someone noticed that if you fired KE rounds at shipping, though, rounds the hit short tended to curve upwards *under* the water and so *could* still hit the vessel, and under the waterline, too! So you ended up with the anti shipping rocket and anti tank rocket switching roles...
I must admit, I found this quite humorous when I read it years ago. As for the veracity of said switch, it's been far too long to remember where I read it, but I suppose it was true enough.
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