I used to have a space on my FAC for a 30-06 but did a one for one swap for .223. I am now thinking of maybe getting a bigger calibre for use in South Africa. Would it be possible to do a one for one swap with an FAC air rifle space that I still have on my FAC? Also whilst on the subject what are your opinions on a calibre for plains game, are there better calibres than 30-06 and 308? I notice that alot of South African guides recommend 30-06 due to its flexibility.