Hi, after researching for ages back in 2008, my plans went on hold after moving across the country, but now I am looking to resurrect my desire for HFT

Amongst the usual Springer v PCP debate I am struggling with, there is the question of calibre.

So please could people advise on the pros and cons of .177 v .22 for HFT type shooting? (Discounting .20 and .25 as they are a bit 'exotic' and so pricier/limited options)

TIA