From the TECH side; Today we look at our Fusion "UMG"(Ultra-Match-Grade) 1911 Barrels and extractor clearance cut. As for fitting with slides with an external extractor. You will generally need to relieve the barrel for clearance for the extractor. This is a basic relief Cut .280” wide and .050” deep and you refence your zero touch-off point at when the cutter touches the underside of the barrel hood. You can also file this if you do not have access to a mill or our shop can perform the service for you. REMEMBER, this only has to be done with 1911’s such as the SIG 1911 which has an external extractor. We just finished the fitting of a Fusion UMG barrel to this SIG Slide and the fit was rock solid! Fitting was very easy; Just the extractor clearance and about .002” off the back of the hood and a match fit!.... This extractor relief cut is generally not needed with most all standard internal 70/80 series 1911 pistols design. Have a Great Day From the Fusion Firearms Family and “Build-On”… !!! Keeping the Tradition of Craftsmanship Alive!!