I finally got a chance to shoot the 396 Mountain Lite with the 180 grain XTPs pushed by American Select. The 5.1 gr load was comfortable while 6.0 grains felt stout but very shootable for a dozen rounds or so. Accuracy seemed good, no signs of crimp failure, no signs of unburned powder, and according to the Hornady data which was also shot with a 3" revolver the velocity should be a strong 850fps. So to keep it simple, 180gr XTP over 6.0gr of American Select thrown with the #16 bushing in my Hornady pistol measure. Thanks again to everyone for their insight.