Finally got the PR4 from Tango Down today. Installation was not too bad but took some time to screw it together using the hex wrench (provided, thank you). A bit of a finger breaker at times. There is a small gap between the castle nut and the device. I'd rather it not be there (gathers junk) but that's probably something I've done.
Anyway, the ASP fits great with it. Feels good. Comes up nicely from any postion without snagging anywhere. Very comfortable.
No, the Crane stock won't close down to the closest position but that's ok because I have no use for that position ... charging handle smacks my nose.
I'll try it out at the ranch in a few weeks but so far, it seems to be the perfect combination (PR4 and ASP) for me.
I'll provide pics when I have time.
ETA: JTrusty, when will the two point configuration be available? I'm thinking about a long hike in the mountains.