I did a lot of testing with 4227 and found that it will raise pressure/velocity as your gun heats up...like 200fps+/-.

I researched it further and found that this was common knowledge among the IMSHA comunitee. I know if you test a few rounds you can be miss-lead into thinking it is good pistol powder, but it is not.

Accuracy will be great one time with 4227. But then you try it again and it will be all over the place. I proved this to myself with the 44mag, the 475L and the 480R...but where it really shows up is at long range with the 460S&W.

You have to keep pouring the H110 into the case until it melows. It is not your primer, it is the fact that h110/296 has a specific pressure that it burns well at. Until you reach this pressure it will show up to 140fps extreme spread from shot to shot, especially with the sedated loads of the modern reloading manuals.

Case in point..my old Hodgdon manual list 26 grains as max in a 44 mag with 240JFP and some new manuals list 22gr as max. When the perfect working pressure is reached it will drop to the single digits...like 6 fps extreme spread. Example: my 44 with a 280castGC needs 25gr 296 to give me 6fps extreme spread in one gun(both Rugers)and in the other SBHH it takes just a little more to obtain this extreme spread result.