I love my L-N-L (old style ejector). One of my few beefs with the L-N-L is when I run out of primers or there is jammed primer in the primer slide. Its pretty easy to let a round or two get through with no primer.  Not only a pain in the a55 to pull the bullets, but now I have powder all over the place.

Here is how I cured this, in about 15  minutes with a 1/4" X 1" roll pin, 1/4" drill bit, a rubber spacer that will fit over the roll pin, and a small brass rod.

Remove the spring from the primer slide, then operate the lever through a full stroke.  This will leave the primer slide at the full rearward extent of its travel. With it in this position, mark the press body directly under the little extension of the primer slide, where the spring attaches.  Remove the primer slide and the crooked "cam feeder" bar that moves the primer slide.  Drill a 1/4" hole about half way through the thickness of the press body (be sure to place the hole far enough away that the spacer will clear the plate during normal operation.).  Drive the roll pin into the hole, then put the rubber spacer over the roll pin ( cushions the impact when then last primer is used). Replace the cam feeder bar, primer slide, and reattach the primer slide spring.   Last, cut a piece of brass rod (or an old coat hanger) slightly longer than the primer tube.

How it works:  After filling the primer tube, place the brass rod (or coat hanger) into the primer tube.  As primers are used, the rod will slowing sink into the primer tube. When the last primer is used, that brass rod will fall into the primer hole in the primer slide, holding it to the rear.  As you return the handle to the up position, the primer slide will come down on the rubber spacer, .preventing you from completing the cycle.

When using small primers, my press now stops after the last primer; on large primers, it usually stops when the last primer is in the slide. I have the rod marked in 10 primer increments, so I can judge remaining primers as I work.

Disclaimer: Since this involves modifying the press, use at your own risk.  I run rifle brass through in two sessions, so I am not worried about breaking off the little spring attachment pin on the primer slide.  If running large rifle cases through in one pass, I would be a little worried...seems like there would be a potential for damage if you were using a lot of force on the upward stroke of the handle and a case suddenly popped free from the die.