I had about the same accuracy as you did with H4227 in my 10" barrel. I found a load that shoots with as much velocity and accuracy was much, much better. I have been using 29.5 grains of VV- N130 and a 125 nosler ballistic tip. This is by far the best results that I was able to obtain after working with AA 1680, IMR4198, lil gun and both 4227's. dave