I have been trying some more powders in my 20 inch barrelled .260. I was given half a tub of H414 so looked at all the different manufacturer's recommended loads with the 120 grain Sierra Prohunter bullet.
The most powder recommended is 45.5 grains on the Hodgson site.
I weigh every charge and check the beam scales with check weights.
Starting low and working up by one grain then half a grain everything was fine until I fired the 45.5 grain load, which gave a blown primer and sticky bolt.
H414 in the .260 would seem to be one of those temperamental powders that give high velocity but quickly go into the red. At least it is so in my rifle.
Sierra recommend 44.2 grains of H414 as the maximum with the Sierra 120 grain Prohunter. This load gave very consistent velocities with a five shot test. A low of 3,004 and high 3,024 so only 20fps extreme spread. This is from a twenty inch barrel so seems rather quick.
I carefully examined each case as I had fired and there are absolutely no signs of excess pressure and the case ejects freely. So looks like a result as far as consistency is concerned.
I haven't fired them at a target yet, however I have ten loaded in readiness.
As the velocities are so consistent, does that automatically mean they will shoot well, or is that a will of the wisp ? Time will tell.
As the velocity is significantly more than that predicted from the test barrels, I am just a little concerned as to why this should be ?
Similarly I am wondering what the effect on deer (meat damage) would be with the 120 grain Prohunter travelling so quick ?