Thanks actually got an answer, from another forum.
Answer #1:
What calibre? On mine for 6.5mm cal it has 6.71 for the (grooves) value. You can change this by clicking on it and typing in your own value if you know it for your barrel. Mine is 6.5CM chambered.
Answer #2:
Grooves = barrel diameter to the base of grooves in the rifling.
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