Here's my opinion on them:
I watched their video. They start out confirming that with solids you need a high impact velocity, so that's at least good to hear them admit lol. The rest though, to me, is just 4 guys sitting around talking about exploiting a demand and marketing the crap out of it. It all sounds great, but when you simply look at the product and what it is and the BC's… I'm sorry but they haven't really made any new breakthrough like they claim. It's, if anything, just a slightly enhanced GMX. Good on them for trying, but Hornady has a heck of a marketing department and a reputation for making every new product appear to be cutting edge and breakthrough technology. I'll admit it works really well on a lot of people lol, no disrespect to them intended either.
Honestly, you can only get so much from the typical copper bullet since it doesn't have the density like lead. Any solid with an actual decent BC is going to be really long because it just has to be.
That length is going to do two things: first, it's going to require a fast twist in order to achieve proper gyroscopic stability in flight. Second, it's also going to reduce terminal performance. A bullet that is unbalanced as far as length vs diameter will result in more sectional density, and more penetration and less expansion. That even goes for lead core bullets, but it's exacerbated with most copper bullets.
Im sure that's one reason they kept them at the lower weights. They wanted to be able to cater to the typical factory rifle twist rates, keep weight lower so speed could be higher, and keep the length down for terminal performance as well.
They still stay 2000fps is the minimum impactful velocity, and I personally would be more confident not dipping below 2200fps, and they also they'll only add about 100 yards more range capability compared to the GMX.
I wish them luck and anyone using them, but they're definitely not for me. There are simply better copper bullet options out there. That said, the factory offerings might be a decent option for the non-reloading California hunter.