Incredibly right angle to the question.
I have not shot them but I have one on order. I was at the SHOT Show where they had a press shoot centered around the cartridge and Savage's rifle. The Savage at the Winchester booth barely functioned. The shooters were having to dig cases from the chamber with a screw driver. Accuracy was Ok. At the Savage booth the rifle functioned flawlessly. Accuracy was same same. What I managed to do was pirate some chrono data and it wasn't too impressive. Extreme spread of just under 500 fps with a Standard Deviation of around 80 fps. Speeds did not pass 2900 fps. We also had a word with the guy who originally designed this round for Winchester a decade ago. He quit and went to another firm when Winchester went ahead with plans on this round. He simply said "It won't work" and that was all. Obviously, it's a work in progress.
I ordered a rifle but I want it for the action to rebarrel to 5mm Remington. The rifle itself is a nasty piece of gun gear. Feels like a toy.~Muir