Has anyone been able to successfully run the MCX with the 6.75" 300 BLK barrel unsuppressed?

I recently had the opportunity to install and shoot with my new 6.75" MCX barrel. With suppressor attached, it functioned like a dream; I had zero issues with the 6 different types of ammunition I fed it.

When it came time to test function unsuppressed, it was a different story. Going in, I had no expectation that it would be able to reliably cycle subsonic ammunition sans suppressor, given my experiences with similar setups. However, I had difficulty with all 4 supersonic loads that I fired through it. The issue: failure to eject. I had a few stovepipes, but most of the time, the gun would fail to cycle because a piece of brass would still be sitting the chamber, most often oriented in a way that it was causing a "double feed" with the live round that was trying to chamber. This would happen anywhere from once every 2 rounds to once every 5 or 6 rounds.

To me, this seems like a symptom of an under-gassed firearm. Just wanted to know if anyone else out there has had a similar issue, and if there is any fix to be had. Or if you have been able to run your 6.75" barrel unsuppressed without any issues. I really want to be able to run this weapon in a short, unsuppressed configuration if possible!