It shouldn't be a dirty chamber. It is a new gun.
Here's a little tip: Just because it's a "new" gun does not mean it's perfectly clean.. ANY new firearm should first be cleaned before it's shot.. Otherwise you have no idea if there's some dust, grit, (whatever) sitting in that chamber or bore and it's simply prudent to ENSURE there's nothing in there before you fire it.
Second - M700 extractors are the most often part failing in that model. Either breaking, improper tension or just plain wear, that part is the one most often replaced - and I get these in for that exact reason several times/year..
Eliminate one variable - clean that chamber first. Wrap some steel wool around a bronze brush that'll fit snugly in the chamber, oil it up and use a high-speed drill for about a minute. Remove, clean and inspect.. It should look like a mirror finish in there..
Now test fire. The shells should come out easily.. If the extract still slips over the rim, then take a good hard look at that extractor. Is it split? Is there a piece missing? Does the lip not protrude fully into the bolt face?
If yes to any of those, you can send it back to Rem (and it'll take 3-4 weeks to get it back) or you can take it to your local smith for a fix - which may take a day or two..
Up to you..