Does it do this while cycling the bolt with no ammo? I was thinking you had an ammo issue at first, but I see you've tried a different kind. I have a sps in 300 win mag that has always fed perfectly smoothe with 150 grain ammo of any kind. Before deer season, I tried a few 180 grain loads to try and find which grouped best out of my rifle. Had a box of HSM ammo loaded with 180 grain bergers that did the exact same thing you are talking about. I'd wasn't real hard to lock the bolt down but was very noticeably different. I just didn't mess with that ammo anymore as everything else I've fed it has cycled just fine. Also, my bolt is smoothe as can be when cycling with no ammo.
If I were you I'd get a chamber brush and make dang sure that chamber is spotless. If that doesn't do it, I'd take it back where I bought it or send it off to Remington. Good luck! Let us know how it turns out, I'm real interested.