IMR 8208 XBR has been out for a few years now but there doesn't seem to be much load info out there. Most search results turn up threads from 2010 when it first became availble. It's supposed to be very accurate and temperature insensative. So I thought I'd try it myself. All shots at 100 yards fired from a Savage 12 FV, glass bedded, bipod and rear sand bag, Nikon 6-18x40. I have not shot much lately, and I'm no expert, so my technique is less than perfect.
Fed 205M primer
8208 XBR 26.0gr - 26.7gr
It was terribly windy but still shot well for the first time. The bare plywood backing tore up the target pretty good too. I loaded some more and tried again a few days later.
26.2gr - 26.7gr
Ok, they all shoot well, I think I'm leaning towards the faster loads. I loaded some more 26.7gr and 27.0gr and tried again.
27.0gr showed some flattening of the primers on 4/10 shots but it shot well. I backed down to 26.7gr
and that seems to be working well. First target, 5-shots (3 in the left hole, 2 in the right hole):
Last target of the day, 1moa high and 1moa low of diamond. Barrel was pretty hot, I shoot quickly.
CONCLUSION: Still need a little more testing, maybe mess with the oal a little. ALL 5-shot groups were less than 1". This powder shoots well with several different loads. 26.2gr and 26.7gr shot the best, and I'm sticking with the higher velocity load for hunting. I have not chrono'd the loads yet but it should be around 3660fps.