I put a 6 RAT together on a Howa Mini with the Grendel boltface last year. Used a Bartlein 1-8tw in light Palma contour finished at 24" & with the shank turned down to 1.090" to be a better match to the Mini's small action. McMillan did a Sako Varmint stock for it; both the action & bottom inlet were spot-on, and this stock was delivered pretty much on time. However, the 2nd stock I ordered from them over a year ago still hasn't made it to me - no idea what's going on there... I've seen very good 500yd accuracy out of Berger 90BTHPs with IMR 4320 - not great velocity, but about all the accuracy you could reasonably expect. Other projects & work on customers' rifles forced me to put this rifle on the back burner where further load development is concerned, but I'm sure looking forward to getting back to it.