Resurrecting this thread to see if anyone has any field reports. I have a case of 1000 Nosler 190's and I can make em shoot quite well, and eject the case, while still remaining subsonic, but no bolt hold open. I have an adjustable block but after a few thousand rounds it's a pain in the ass to try and adjust it.

Admittedly I still need to try other powders, but right now my work station is set up for priming. I am about halfway through priming a 3 gallon bucket full of 9mm, but as soon as I am done with that I will be back to load development.