Just a suggestion and maybe you've already done this. Run the ramrod in until it stops. Mark the ramrod with a pencil even with the muzzle of the barrel. Withdraw the ramrod and lay it on the side of the stock, with the pencil mark even with the muzzle. That will show you the area where it's hanging up.
Pull the barrel and then run the ramrod in. That'll tell you if it's the lug.
-Ron