It'll work fine. I've run a 30 cal Heathen on a 7, 6.5 and 6mm, run a 6.5 Heathen on a 6mm, etc. You should consider something other than a radial brake though, they aren't as effective as a properly ported brake and they push some of the blast down which, as you can imagine, is less than ideal when/if shooting prone.