I cut a few coils off the spring behind it once I had ordered a spare and it made it wayyy smoother to operate and no negative effects over 1,000rds of 6 and 6.5 creed
I would recommend a nucleus as someone said now that the growing pains seem to have passed although I’ve had less than 5 light strikes over her lifetime no complaints still running 16# spring and original bolt head on a preorder left hand short action