I used to favour 177, but had too many squirrels and magpies with their brains hanging out, not dead. That's not bad shot placement is it ?
Never happened once with 20 cal, when I converted after my extensive field trials over three years of cross species , cross environment actual shooting.
Shoot through IS real with 177 (not enough energy left in quarry), 20 may not be much bigger, but apparently sufficiently bigger _
I shoot 22 and 177 too, but 20 is Best IMO for All Round Hunting use as it's bigger than 177, shoots nicer in springers, kills stuff without 'shoot through' not killing stuff, doesn't have loop of 22
If going after one specific quarry, in one environment _sure go for the ideal set up.
20 will do a better job All Round.
It's like arguing if front or rear drive cars are best, and then comparing with a 4x4, which can go anywhere 'really well' ....