RE: winchester 777
It could be the make of the rifle as well as the primers. There are some rifle primers that sit different in rifles and hence give people problems. Whether this is the case with you I could not say. So far, from all the reports I have read on the Winchester Triple Se7en primers, they have been all good. Do you have another rifle to try these primers in? Also was the hammer/firing pin/what ever striking and denting the primer?