Those who dismiss the XC have probably never shot one . Is it value for money, possibly not . There's nothing wrong with the .243 , I only changed because I was bored and had an itch to scratch .
In real terms the 6XC betters both the CM and 243 in accurate barrel and brass life . If throated to Tubbs 0.160" freebore , the CM will run over magazine length approximately 500 rounds before the XC if maintaining the same bullet jump .
The Creedmoor of course will win on velocity, if only by a bit .
As for the XC being dead , Steve Kershaw told me he is chambering 15 XCs to 1 CM .
Is it worth changing from the .243 , depends on your round count . But given availability of components for the options , probably be wiser to go fast twist 243 .
In real terms the 6XC betters both the CM and 243 in accurate barrel and brass life . If throated to Tubbs 0.160" freebore , the CM will run over magazine length approximately 500 rounds before the XC if maintaining the same bullet jump .
The Creedmoor of course will win on velocity, if only by a bit .
As for the XC being dead , Steve Kershaw told me he is chambering 15 XCs to 1 CM .
Is it worth changing from the .243 , depends on your round count . But given availability of components for the options , probably be wiser to go fast twist 243 .

