It all comes down to the barrel liner Phil
thats what makes these rifles so unique you can get different twist rates for different cals
Plus you can change the rifle from 177 to 22,,to,25,,to30cal
but you need to buy the liner ,,,pellet probe,,and mag for what ever cal you change to
Iv had sh*t loads of rifles only one iv ever felt was part of me and that was the webley raider single shot
Why the hell i got rid i dont know
it looked like sh*t it was the cheapest rifle iv ever bought but it was accurate very very accurate
Until now this crown is some thing else and then some iv watched loads of u tube vids on it shooting out to 100yrds
pellet on pellet just about .
And now they have slug liners for them to( but i think these are for fac level rifles only i could be wrong on this mind )
but its the liner that makes fx rifles special.
So get watching some u tube vids on them there are loads that will answer your question a lot better than us