The 40gr; Hornady is too long for a "nominal" 12 twist, which may, or may NOT, be actually 1-12" twist. I have an early Savage barrel that is more like 13.25" twist. It shoots the shorter 39gr. Sierra or Nosler pretty well, but scatters the 40s like a shotgun. If you look over on 204ruger.com, there's a photo of the 39 Sierra, 40gr. Nosler, and 40gr. Hornady, and looking at the boattails of the bullets, you can see that the boattail of the Hornady is MUCH longer than the other two, making the bullet too long for a "nominal" twisted barrel.
On a real 1-12" twist, the Hornady is barely stable, and usually shoots pretty good.
I just don't use the Hornadys, and usually stick with the 32s and 34HPs from Midsouth, They are fun for short range and called coyotes.
