Wore the throat out of a 223 ai....I set the barrel bak and chambered to 222which has become my favorite...but the 20 tax is a close second....depends on the day I wouldn't want to be without either...both sako 461s......also never leave without a standard 223..for me the gain just wasn't worth the effort..not saying I didn't like it as I did...judo in the field shooting prairie dogs....the standard 223 was just as effective at the same ranges...not on paper but in the field I couldn't tell much diff.