I have a Christensen Arms. I had a custom one built about 5 or 6 years ago. I had them build me up a 30-378 on a Weatherby Mark V action, lightweight stock and a 28 inch match grade barrel. This was before my days of being more informed on the custom builds and doing some research. I got caught up in the fad at the time.
When I received it, I noticed it wouldn't eject the shells very well. The ejector spring wasn't correct. I took it to a local gunsmith who has experience working on the Mark V actions. He took the action apart, and it was full of rust. Remember, this was a $4k+ custom.....
I called up J. Mongle and company and read them the riot act on this. They promptly had me return it back to their factory and they sorted it all out in a quick turn around. They denied there was ever rust inside the bolt. But they did sort it all out.
At any rate, my build from them does indeed shoot and shoot very well. I'm typically at 0.5" MOA with it with factory, so I can't complain. I got lucky with mine. I have a lot of confidence in this rifle and its taken many critters over the past few years without fail. I feel like there is not a shot I can't make with this rifle.
That said, I just had a purpose built mountain/backpack rifle built up in 300 WSM, and it wasn't by CA.....
Be aware if you buy it....you either love CA rifles or you hate them. You don't see many people selling 0.5" MOA rifles so if its a used CA, it could be one of those that groups like a shotgun!