R700 hard bolt close

Spectre3

Private
Minuteman
Sep 1, 2019
36
52
NC
I bought 2 boxes of Nosler 140gr Ballistic Tips for my 6.5 cm aac-sd back in November with the intent of it being my go to hunting round. The other day I finally got to attempting to shoot it for zero and to see what it would group. Out of 40 rds, the bolt wouldn’t close on 5 and was very hard to close on 6 more. The rest chambered with no issues. I’ve never had this issue with any other ammo, including cheapest of the cheap S&B fmj. There’s nothing odd looking about the “bad” rounds compared to the ones that fed properly. I ended up not shooting any of the rounds just in case. Is it safe to say this is an ammo problem or did I somehow miss a tight chamber after all this time? The S&B and Hornady match that I’ve used prior have never had any issues.
 
Extractor, Head space, throat clearance.

If the bullet doesn't have scoring on it after chambering, you can rule out throat clearance. Head space you can measure with a comparator.