Problems with Savage MKII BVXP

This past Saturday I went to the range and to bench test my Savage MkII BVXP. I only had about 50 rounds through it since it was bought. I was shooting dime size groups at 50 yards using CCI Minimags. They ran fine. I then switched to some CCI standard velocity. They were also grouping well, but had trouble with the rounds not ejecting from the chamber after I shot about 20 rounds. The only difference I can see are the minimags are clad, whereas the SV's are not, just lubed. Is the lube what is cause the rounds not to eject, or something else? I ran a boresnake through, but they still would not eject.

I was having similar issues with mine, some rounds would eject fine others wouldn't. I found some build up where the ejector grabs the rim, cleaned the front of the bolt and haven't had an issue since.