I was shooting a marlin .17 (no idea what the model was) with my uncle at the range a half a year ago. It would put bullets in the same hole from 1-7, then in an inch until 15, then they would break a little apart. This was at 50 yards on a brand new gun I believe. There could be more to the problem, like the gun being new, but he said it was a common issue and I'd trust his logic being a gun smith.
Another problem is up here where I live there is rarely less than 20 mph of wind, and have fun shooting a 17 grain bullet in that at anything more than 50 yards.