At 12 ft lbs placement not pellet weight is critical, it matters little if you use a heavy pellet or a light one if it is in the wrong place. At 12 ft lbs that in my book is the head only.

I had several years with both 177 and 22, much as I wanted to use the more macho .22 I found 177 far better as it is flatter shooting and easier to hit the spot perfectly. I cant see 20 at this energy level being any better than 177 at all. At 20 ft lbs then certainly it will be the go to caliber though but not 12 ft lbs.

A