Board Thread:General Nerf discussion/@comment-3362895-20200108112058/@comment-30049823-20200108165830

Well if they still sell them at the place you bought it, you could try for an exchange. Most people don't have any trouble with RIVAL ammo.

If that's not an option, it's noteworthy that X-Shot Chaos rounds are consistently ever-so-slightly larger in diameter than RIVAL rounds... So to make RIVAL rounds work better in springers that seem gutless, all you really need to do is shrink the breech/chamber diameter ever-so-slightly for a better air seal. (The balls are squishy so X-Shot rounds will still work unless you go overboard)

You might be able to carefully heat it up and compress it a bit, or just line the interior with a layer or two of tape. (Depending on the thickness of your tape, you might not even need to go around the entire interior circumference)

(* CAVEAT: I haven't tried either; my Orbit and Meteor from Burlington both seem to work fine. But the tape trick works for sloppy-fitting darts in a Triad)