With 250g barnes MZ, my disc rifle shoots 1'' groups. 300g barnes, sst, knight jacketed soft points and 310 lead hollow points tend to all shoot into 3'' or so. When I shoot these same bullets with 100 grains (pyrodex pellets), they all shoot a little better. My sense is its just like working up handloads for a rifle--you need to find the right combo. I've used the 250g barnes on mule deer and antelope out to 219 yards. I've never recovered a bullet and performance has been deadly--they simply drop. For elk, I use the 300 grain barnes of jsp and put up with a little less accuracy.