Re: Another Marlin model 60 problem
I agree with Army on the WD-40.
One of my favorite rifles is my Glenfield/Marlin mod 60. I don't think you're seeing leading. I think you're seeing powder fouling. I know people who shoot 22's competitively with plain lead (not copper washed) bullets & they never ever clean out their barrels. They just clean the action & get great accuracy.
The mod 60 needs to have the stock removed (one bolt) & the 4 screws that hold the action onto the reciever taken out. Use a toothbrush & WD-40 to get all the powder fouling off all the areas of the action. Take the bolt out & wipe it down & clean out the area inside the receiver where the bolt rides. Also make sure the bolt spring is clean. Use WD-40 everywhere you can. Regular gun oils are way too thick & cause too much friction in this gun. Don't listen to those who say WD-40 is not a lubricant-it says "lubricates" right on the can. As has been said You want to avoid building up powder fouling crud & WD is the best I've found in this gun. You should be able to shoot any 40 grain ammo however cheap if your gun action is clean & your bolt is sliding freely. The only ammo mine hasn't loaded well is the old "truncated" shaped bullet. HPs shpould be no problem.
"duds" are usually caused by light primer hits in dirty guns.