I've got both the Marlin model 60 and Glenfield model 60. Both shoot extremely accurately and function fine. They do however need to be cleaned especially the bolt and bolt carrier as this area tends to get full of powder residue and will cause FTF or FTE situations if left uncleaned for a long time.

It's pretty easy and straight forward to take them apart. Two screws on the stock, the big one and the rear trigger guard screw. (No need to take out the front trigger guard screw) you can then lift out the barreled action. From there you will either (depending on how old the rifle is) need to push out a couple pins one at the front and one at the rear of the action or take out a few small screws in the same location.

After that is done you will be able to take everything apart and clean it well. Look on You Tube there are a few pretty good videos on how to field strip the model 60.

Good luck!