My 6mm Rem is my go-to 1000 yard rifle with 90gr Sierra FMJ/BT. It's been fine-tuned, and the load for that kind of shooting takes serious development. But the cartridge is superb. 100yd range means 5-shot ragged holes all day.
Barrel twist is a big factor in finding the right load combo. Then stock mounting--floated? Piller? etc... Trigger helps, but isn't your first focus. Lots of factors, many just in the load itself.
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