Here are the parts from two Mk IIIs, one from a steel barrel, and the other from an aluminum Lite model. Changing the parts on the steel guns is easy. Disassemble the barrel from the lower receiver and you will see the little steel pin barely protruding from the underside on the left of the barrel. Tap on the bottom of the barrel with a non-marring mallet, or hickory hammer handle, and the pin will work out. After it is out you can remove the LCI and insert the replacement hole-filler.
The problem in changing arises if you have the Lite model. The aluminum grips the steel pin and it will not come out. I had our Lites apart three times trying to remove the pins with no luck. Here is how you do it. Put a cutoff disc on your Dremel tool and very carefully attack the LCI. Be careful so you don't mar the finish. The LCI has a metal part on the upper side, and after you have the polymer part removed, let the cutoff disc ride against the metal part and cut a groove into the pin. Use good lighting. Use a small screwdriver to pry the pin out a bit, and then you can grip it with some tiny pliers and remove it.
We have run our guns since making the change and they have not choked since. Using a Dremel tool on your guns is usually not recommended, but in this case I had to make an exception.
