Just got back from the range with some interesting results. I had some 255gr Barnes loaded with 33gr of RL-7 (max book load) in Star Line cases and some in Jamison. I also had some factory Buffalo Bore in the same weight. The rifle was a Marlin 1875 (336):

Star Line: 1887, 1947, 1953
Jamison: 1874, 1858, 1877.
An honest 1.75" group at 100, and about 1.5" low of center bull

Buffalo Bore: 1970, 1977 but almost 8" high and 2" right.

Perplexing to be sure. The 200 gr Sierras shoot right at 1" about 2" high at 100. Load was again max book load of 35gr RL-7.

A good principle to guide me through life: “This is all I have come to expect, standard lackluster performance. Trust nothing, believe no one and realize it will only get worse…”