Get Your Extractor Right the First Time
by Bob Londrigan, published in Front Sight Magazine, November 2008
The extractor is probably the most crucial component to a reliable gun. Since it is especially important in 9, 38, and 40 caliber guns, I think an in depth discussion limited to these calibers will be of benefit to most competition shooters. Realize that although there is a somewhat different procedure for 45 cal extractors, many of the same concepts apply.
If you presently have a well functioning extractor, you can still benefit from having a backup that you know will work reliably in your gun should you need it. Extractors can wear out or break and need to be re-tensioned from time to time. They will usually give you problems either right before a match or during. It is a better plan to have a backup already tuned and tested in your gun rather than re-tensioning a problematic one or even replacing one that is broken. In either case, knowing how to tune and install an extractor is a useful piece of knowledge to have in your arsenal.
First we need to look at how an extractor functions in a properly tuned gun. The cycle starts with a loaded round in the chamber. When the gun goes off, the slide and barrel move to the rear. The barrel then unlocks and moves downward and slightly to the rear until it stops on the frame. The slide then continues rearward taking the extractor with it. Since the extractor hook is over the rim of the brass, it starts to pull the spent case to the rear out of the chamber. It will continue to pull the case to the rear until the case hits the ejector. Once the case hits the ejector, the ejector rotates the case around the extractor hook until it releases from the hook and is ejected out the ejection port of the gun. The slide continues to the rear and the next round in the magazine pops up. The slide comes to a stop against the frame and then begins its forward travel. Once the breechface gets far enough forward it contacts the top rear of the next cartridge and pushes it forward until the nose of the bullet contacts the feed ramp. The bullet continues up the feed ramp smoothly and, as this is happening, the rear of the case cams up the breechface. It is important to understand that the case is coming up the breechface at an angle and that it straightens out at the end when the cartridge is fully in the chamber. The cartridge cams up the breechface, and the rim of the case slides up under the hook of the extractor. The barrel moves upward and forward into battery, and then the gun is ready to fire again.
It is important that this process is smooth and that the cartridge is under control during the entire cycle. You do not want the ejector to hit the case and knock it out of the gun. The case must stay in contact with the hook until it has rotated approximately 90 degrees and the extractor groove on the case contacts the tip of the extractor and the rim clears the hook. Likewise during the feeding cycle, you want the casehead in contact with the breechface and the nose of the bullet in contact with the feed ramp all the way up into the chamber. You donít want the bullet bumping the feed ramp and bouncing into the chamber. Some causes of this type of feed problem are overly fast slide velocity at the time the ejector strikes the case, feed ramp geometry, bullet profile, and OAL of the bullet. Length of the ejector (or lack thereof), shape of the ejector, or shape of the extractor can also contribute to the problem.
Now that you have an understanding of how the extractor works, we can talk about how to install this part. First, check your firing pin stop for fit to the slide. EGW makes a nice gauge to check the width of the firing pin slot in your slide. Compare this dimension with the width of your firing pin stop. You want the firing pin stop to fit the slide snugly. You may have to get an oversized firing pin stop if your slide is oversized in this area. Fit a new stop if this dimension is much more than 0.001 over the dimension of your firing pin stop. Prior to fitting the width of the stop make sure your slide is wide enough to accept the raised position of the firing pin stop in the middle of the stop. If this dimension on the slide is too narrow, widen it a little on the slide using a file.
Once you have the firing pin stop sliding into position snugly it is time to work on the extractor. Begin by making sure the firing pin slot in the extractor is wide enough to accept the firing pin stop. If it is not, you will need to file the slot a little wider until the firing pin stop slides in easily. Then install the extractor in the slide and check to see if the firing pin slot will fit in. You can use the EGW gauge again at this point. If the firing pin stop is too tight then take a little off the extractor or the firing pin stop until the firing pin stop can slide in. Make sure you keep all surfaces square so that the extractor is straight up and down when it is finally installed. The extractor should not be able to rotate in the slide (this is called ďclockingĒ) as this can cause malfunctions, and inconsistent extraction. It also helps to take the sharp edges off the sides of the firing pin stop so you donít get false readings about how tight it fits in the slide.
Now take the extractor out and begin working on the hook. Most stock extractors have a sharp, square hook out of the package and will need to be smoothed up for best reliability and feeding. First take some of the brass that you are going to use and test how the hook fits the brass. You need to know whether the extractor will contact the brass on the rim or in the belly of the extractor groove. This will affect how you tune the hook. If it is going to ride in the belly of the extractor groove (this is what I prefer), then you need a little bit more of a radius on the bottom of the hook. If it is contacting the belly, the belly of the extractor will need to be smoothed. Radius the bottom of the hook so that when the extractor cams over the brass, the hook will slide smoothly. Also slightly radius the bottom of the hook from front to back. This will help the brass cam under the extractor as it goes up the breechface at an angle. This is important because if you donít break this edge, the extractor will gouge the brass and may stop the slide from going forward.
Once you have tuned the extractor, re-install it in the slide and check two more dimensions. The distance between the breechface and the extractor hook needs to be at least 0.064 inch. (You can use a 1/16 drill bit to test for this. If it fits under the hook you are in good shape.) This is so that there is enough room for the brass to cam up the breechface at an angle without binding. If you need more clearance you can take a little material off the back of the firing pin groove on the extractor. This will let the extractor move a little farther forward. Next place a piece of brass under the extractor and push it back against the breechface. The brass should not contact the extractor tip at the top of the extractor groove on the brass. If it does you will have to remove enough material from the extractor for clearance.
Now set the extractor tension Ė the extractor should hold the case firmly. Too firm is better than too loose. Check to make sure the brass slides smoothly under the extractor. If you feel a catch, figure out where the edge is and round it a little more. Donít go too far with this or you wonít have enough hook to reliably hold the brass in place. If the brass is sliding smoothly under the hook on the extractor and you still get a stoppage as the round slides up the breechface, make sure you have enough clearance between the hook and the breechface for it to cam up and that it is not catching on a sharp edge on the firing pin hole. If you are ok in these two areas, take a little tension off the extractor until you get smooth feeding.
Once you are done you should have a reliably extracting gun that throws the brass consistently out of the gun. Test fire the gun to check it for function and make adjustments to the extractor tension if needed. The tension on the extractor should be checked each time you clean the gun and readjusted back to the setting that you found works best if it has changed. The extractor channel in the slide should be cleaned regularly also so that the extractor can move in the tunnel and is not restricted in its motion by compacted grease and dirt.