Engines, I think you've completely missed my point.
I said 20mm is for air-to-air not ground targets. Soft or not - although, yes, it could do soft targets. My point there is high rate of fire. Not sure what you mean by "easy" air-to-air targets. A few HE 20mm rounds close to the aim point remains an effective weapon.
I did say that I too think the 27mm round is a good compromise. But there were other possible solutions to breach pressure apart from the land-removing driving band leading to short barrel life. But I still think it's a good round.
As for F-35 hating, sorry, you've hit the wrong guy. I'm sure you've seen enough of my posts to know I am not anti-F-35. Just because I question things does not mean I don't want it to succeed. I see the faults in lots of things, doesn't mean I want them to fail.
Thank you.
Courtney