So I put 250 rounds of American Eagle 230gr (same ammo used by the HK armorer during testing) down range today with the USP and experienced 3 failure to feeds as described in my initial post. Somewhere in the middle of my shoot, I decided to try and replicate the malfunction by deliberately limp wristing while shooting, and to my surprise, the firearm had zero issues. So ruling out limp wrisiting, I thought maybe somehow my strong side thumb was making contact with the slide and slowing it down since I'm not a thumbs forward shooter. I went ahead and deliberately pressed against the slide with my strong side thumb and once again, the firearm had zero issues while shooting. Anyways, this thread can stay open for replies and/or questions, but I think my USP is going to find a nice spot in the back of the safe somewhere where it will remain since I don't feel like spending anymore money trying to figure out what's wrong with it.
Just got off the phone with HK and the firearm is going back in and will remain with HK for a longer than normal period of time so that it can be tested further. Their customer service did right by providing me with a shipping label too. Just wanted to update this with that info. Will report back sometime in the future lol.
So this thread can be concluded. HK is replacing the firearm. My USP will be exchanged with a new USP when their next shipment of USPs arrives in a couple of weeks. It's still not clear what the cause of the malfunctions is and I'm not sure if they are planning on continuing any sort of testing/evaluation of the firearm to try and identify the cause. I am extremely pleased that HK offered to replace my USP rather than have me continue to be without it. Thank you all who contributed to this thread.
Good for you! HK did the right thing. Despite all our praise for HK firearms, a lemon will sneak thru QC and ruin a new owner's day. Glad things worked out for you in the end. And now the wait beings....
Good choice imo