Here is a pic of how I lowered the front lip. From my calipers it looks to be about 0.120 or so total depth, or about 1/8" or a touch less, that's about double what it is originally. These are duramags. I sketched it out via pencil on the front so I had a "line" to go down to.
I might also add, dis-assemble the mag, taking out the innards and spring. Then re-assemble after you're done. Allows you to clean out any filings as well, that way.
I might also add, dis-assemble the mag, taking out the innards and spring. Then re-assemble after you're done. Allows you to clean out any filings as well, that way.