I doubt you have damaged your rifle, but a competent smith should be capable of inspecting it for a relatively small fee. You don't mention what your sizing issue was, but suspect that you have been full length sizing and head spacing off the belt rather than the shoulder. JE has given a great explanation in the past about the use of the belt for reliability for these belted cartridges. The problem becomes that this method of head spacing stretches the case repeatedly above the head with each reloading cycle and results in case head separation. If this has been you error in sizing, get some new brass and start with that and only bump the shoulder back as required after the first firing and you should be good to go..