Talking with Mayo, I got some clarification on the "conversion of a 1911" to fire blanks. The first part which causes confusion is what type of blanks you plan on using. This is important, because there are two approaches to this conversion depending on what blanks you use. Most people will just tell you the "one method".
There are two blank sizes. If you get the small blanks you will not need to enlarge the ejection port in the slide. If on the other hand you will be using longer blanks, you will need to enlarge the ejection port openning in the slide. This is the one piece of information that is often missed by less experience people. See the photo below
Next is the barrell itself. Here in the photo below, you will see that the "locking Lugs" have been ground down. Also the Barrel Ring has been removed, and the hump or curved peice holding the "barrel ring" is also grounded down. Notice [A] and [B] in the photo, [A] has a rounded shape, where [B] has been ground down in a flat/straight angle
Finally you will need to tap (thread) the barrel, and plugged but with a center openning
Here is a nice detail site given instructions
http://90thidpg.us/Equipment/Projects/1 ... index.html