The ejector rod is basically a 2 part assembly with a few springs thrown in the mix. The outer tube is the part that has that knurled tip under the barrel and the center pin is retained by it's shape and spring loaded to push the bolt for the cylinder release to the rear when the cylinder is closed. When you push on that cylinder release the bolt shifts forward and presses on this center pin so that the rear is flush with the recoil shield and the front under the barrel presses the forward lock clear of the tubing part of the ejector rod. It's rather common for the center pins to be just a hair short and this will result in the center pin being a bit recessed in relation to the surrounding ejector rod tube when that center pin is pressed all the way forward. If you park the cylinder in a slightly open position so that you can clearly see the end of the ejector rod what you should see is that the center pin is slightly higher than the surrounding tube. If it's not, you file or stone that tube until it does project slightly when fully pressed forward.

What all this means is that you may need to stone the end under the barrel. Two points. One is that the center pin only needs to stand proud of the ejector rod by 0.002 to 0.006 inch. While 0.010 inch won't cause any harm you really don't need to go at it with a grinder. Second, material removed cannot easily be put back. So, put on some readers and look closely to confirm a need to do any work in this area and work slowly until you achieve a smooth release of the cylinder.