I machined my bolts for the extractors from Gbull and found a little interference with the drum and the feed lips I made. Before the extractors were in the bolts, the bolts all cleared the magazine and feed lips, but with them installed, there was just a little interference. I missed this when I drew up the feed lips. The magazine would have needed just a little clearance with or without the feed lips. I had to put a small radial (or arc) cut in the lower 1/16" sheet brass cover of the magazine and then add a 1/16" x 1/16" relief in the feed lips. I could have gotten by with less clearance, but did not want to do it twice and figured a little extra clearance here wouldn't hurt anything.
Extractors from GBull were very accurate to each other but were a little off from the .dxf file. I did have some extractors from Cutter from years ago when I bought the bolts and forgotten I had them (actually I had misplaced them). Cutter's matched the dxf but varied a little more than Gbulls. Gbulls didn't vary more than about .001" He said he had them wire EDM, Cutter's were milled. I checked them out on a optical comparator I made a dummy bolt and made a few samples on the cuts/cross hole for the extractors. If I put the cross hole on location for the heel of the extractors, Gbulls extractors were about .067" from the face of the bolt to the underside of the extractor. Cutters were much closer to .055". I decided to move the cross hole toward the rear and used Gbulls since his were already hardened. I figure I could use Cutter's as spares and may just need to take a little material off the heel to get those to the.055" from face of the bolt to underside of extractor. This way gave me the most options with extractors from two sources.
I advise anybody that is going to fit extractors, make a dummy bolt first to get the setup right and tweak to get what you want. I had a total of 23 bolts and got them all machined without scrapping any.
Here are some pics