Thread: Winchester primers

I brought some of the above from the local gun shop. I loaded them and half of them work and half didn't. i tried the ones that didn't work in 3 different rifles. When I took the ones that didn't work back to the shop he told me that it was how I loaded them. Is this possible or is it the primers fault. I did nothing different when loading these ones to all the other ones that I have loaded. Any ideas? Thanks.