I just fired one of my 300ultramags for the first time after having a new Gaillard medium varmint barrel installed.Using 180gr ballistic tips and r-25 my worst group(of three) at 100yards was .580" and my best was .050"(one slightly oversized hole).As with my other 300ultramag rifle the optimum charge so far appears to be 95gr of R-25.I have yet to do some more load development but so far this combination appears to have a great accuracy potential.As an added bonus the gaillard barrel seems to copper foul much less than my other barrels.