I'm cutting and pasting my original post from that link, so I left out all the other useful replies. There is some real good info from Bill_Z in there, but I'll limit this to what I wrote and my diagrams. If you have an e-mail address you can send me, I can probably cut and paste the whole thread and send it to you.
Several people asked me how to fit an extended ejector. Although there are some nice tutorials online, I thought I would try my hand at doing a diagram. I'm going to assume anyone trying this understands how the ejector fits in the gun, and how to remove the old one. My focus here is to show where to cut angles for proper ejection.
So, first things first. Inspect the ejctor. Many aftermarket ejectors have oversized studs. Make sure the ejector goes into the frame without excessive resistance. If you have to hammer it in there, realize it's possible that it will be too tight to fit flush with the top of the frame. The easiest thing to do is try one leg at a time, twisting it back and forth while inserting the leg. If it is too big, take off a little material and retry.
Next, make sure there is not excessive casting flash on the bottom of the ejector, or where the legs meet the bottom of the ejector. If there is, file it away, or you will have a difficult time inserting the ejector flush.
Before you do any cuts, it should look roughly like this:
Once you can get it in all the way with little trouble, you can make the relief cut in the front leg for the ejector pin. There are two methods. One is to simply drill through the hole in the frame. The second, which is the one I prefer, is to make a witness mark, and then pull the ejector back out. Then, using a VERY small round file, file a half round relief in the front of the front ejector leg. Re-insert, and look to see if there is enough clearance. Keep trying this until there is enough clearance. It's important to stay centered up and down, without over cutting, but cutting too deep is okay. The reason I prefer this method is because you avoid raising any burrs drilling into the frame. See the red arrow in the diagram.
After this, install the ejector, and drive the pin in. Drive the pin from the right side to the left. Doing it the other way will most like bend the pin.
Next, we'll file the appropriate clearance angle. Using a file, file the front face of the ejector (see red arrow in following diagram. File this angle the same as the angle of the rear of the magwell. Make sure you put some tape on the tip of the file to avoid scratching up the magwell. This cut should not exceed 1/2 of the ejector face, and preferably closer to 1/3.
Now, looking from the top of the frame, file a 45 degree angle, as seen in the diagram. Put some tape on top of the frame to avoid scratching it, and consider using a safe sided file. This cut also need to be very shallow, as in 1/3 of the face.
When you look at the face of the ejector, it should look something like this:
When cutting these angles, make sure you take your time, and try to make sure you keep your file face squared up. If it's an extended ejector, and you make a mistake, cut it back square and start again. I hope this helps those who have IMed with questions.