Well finally was able to lay hands on the 165 and 175 Matrix and got out this morning to do some testing on them. Load and climate data are on the target:
As you can see I hit the upper limit with the 165's and H1000. There were no pressure signs at 58gr, but at 59gr there was sticky extraction and extractor marks on the case head. I did not hit the max end with the 175's, but was pleasantly surprised to find that they would indeed stabilize out of my rifle. I stopped at 54gr as that is all I had loaded. Any guess as to where I might hit pressure signs?
I do not have a chrono so I cannot provide speeds on these yet. . .
The rifle is a Model 70 that has been worked over some. Barrel is a 1:10 twist McGowan, 24", SS, #2 Shilen contour installed by Sin Arms. Stock is a B&C ultralight medalist. Scope is a Nikon Monarch 4-16x42. Rifle as pictured is 9.5lbs:
God bless fellas!