I won't call it boring, because we had lots of fun, but the CM9 fed ~150 rounds without a hitch, and that's with my inexperienced sister and her also inexperienced boyfriend shooting it some. I just though I'd make sure and get the good experience registered here to balance out some of the trouble reports.
I had a couple of first rounds hang up under the feed ramp in the first 100, but none this time, so I'll just call them break in hiccups.
Now I just need to get more serious about training with it instead of just blasting at dead hard drives. While that's fun, the misses were not that informative.
My MK40 is so boring too. No issues to date. 500+ rounds.