There's an article in "Precision Shooting", April or May relating to accurizing leverguns. Biggest issue seems to relate to the bearing of the locking bolts. If they bear unevenly as in Winchesters(family; 92'ss, 94's, etc) with 2 lugs/bolts. The Marlins with only one bolt seem to be more consistantly accurate. The Winnys can be so tuned to good accuracy, by bringing the bolts into even bearing.

precision is group shooting, accuracy is hitting your intended target.