Ejection Perfection

by Bob Londrigan, as published in Front Sight Magazine, August 2003

 

Consider this scenario:  You’re shooting well – making your hits, with no misses or errors, and all in good time.  Then suddenly a round stove pipes, or you experience a failure to feed.  Your gun’s lack of “ejection perfection” has just cost you the match of a lifetime.  It’s time you perform some tuning basics to get your gun performing with 100% reliability.  One of the most important factors in reliability involves the ejection cycle.  The gun must extract and eject each round every time without fail. The key is to get the gun to do the same thing every time it cycles. This article takes a look at some of the smithing you can do to accomplish that goal.

To ensure the gun is consistently reliable as it feeds the round under the extractor, the round must feed out of the magazine, up the breechface, under the extractor, and into the chamber in one smooth, controlled motion without any jumps or hitches. By tuning the extractor you will enable the round to make this transition smoothly. Once the round has chambered and the gun has fired, the next function of the extractor is to pull the case out of the chamber and hold it until the case hits the ejector.  To enable proper ejection, it must hold the case firmly but not so tightly that the rounds have difficulty feeding from the magazine into the chamber.

Begin by making make sure your firing pin stop is properly fitted.  Check for fit in the groove on the extractor while the extractor is not installed in the gun.  Then install the extractor and make sure the firing pin stop is able to slide into the extractor groove while the extractor is installed in the gun.  If it cannot, remove enough material from the side of the stop until the stop fits snugly. If it slides in too easily, make sure the extractor cannot rotate.  This is referred to a “clocking” which causes erratic extraction and feeding.  If your extractor is clocking, you must replace the firing pin stop with a one that is oversize and then cut it down to fit snugly. After fitting the firing pin stop make sure there is enough distance between the breechface and the hook on the extractor to let a round cam up under the hook.  I check this with a 1/16-inch drill bit.  You should be able to slide the round part of the drill bit under the hook. This means you have at least 0.0625-inch clearance. This dimensional clearance will work on most guns.  If this dimension is too small, you can file the aft portion of the slot in the extractor to let the hook float farther forward.  You can also file the hook to get more relief, but it is preferable to work on the slot and keep the hook stock. Once you have fit the firing pin stop you are ready to tune your extractor. 

The extractor must be tuned so that there are no sharp edges for the round to slide over as it rides up the breechface under the extractor. It is important to round off all sharp edges as shown in figure 1.

Figure 1 – A tuned extractor on top; untuned, stock extractor on the bottom.

Bevel the bottom of the hook and the belly of the bottom groove on the extractor. On 45‑ caliber rounds, you want the rim to ride on the belly of the extractor.  However, for 40- and 38-caliber rounds, it works better if the edge of the hook rides in the extractor groove. Adjust this distance if necessary. The bevel on the front of the extractor should match the angle on your brass.

 

Figure 3 - Extractor hook holding 38 super brass

At this point, you need to adjust the extractor tension.  With the firing pin stop installed, slide a round under the extractor and check the tension.  It should hold a loaded round firmly, but you should not have to work to push the round under the extractor.  There should be enough tension to hold the round against the breechface, but not so much that it stops the round from feeding up the breechface. Bend the extractor until it produces this level of tension. Then check that the round slides under the extractor smoothly.  If you feel any resistance or hard spots, roll the offending edge until you get smooth feeding.  Go a little at a time until it you get it right.

Another option is to install an Aftec extractor.  Instead of bending the extractor, the Aftec has a set of springs that provide tension.  There are a couple of tricks to fitting an Aftec. There is no need to tune the edges because they have already been beveled.   The Aftec needs more clearance between the firing pin stop and the extractor because it must be able to pivot slightly on the firing pin stop.  The slot in the Aftec also has a radius cut in it.  You have to radius the edges of the firing pin stop to match the Aftec radius.  Lastly, check the hook-to-breechface dimension as described for the regular extractor.  If you think you have too much tension, you can adjust the tension of the springs slightly by compressing them for about ten seconds before installing.

Now on to the ejector.  For most competition guns I recommend an extended ejector because the longer the ejector the sooner the round will eject.  This is a good thing. The ejector can be shaped to affect the angle at which the round leaves the gun.  The higher the impact point, the lower the ejection path.  I prefer to bevel the ejector from the top and the bottom at about a 10-degree angle.  This creates a blunt point on the extractor with an almost flat face.  Since the round contacts the ejector at only one point, this produces a more consistent ejection pattern. A contact point about 1/3 of the way down the face of the ejector usually works well for scoped guns, whereas about 2/3 of the way down works well for non-scoped guns. However every gun is different and these are just starting points. When you are trying to adjust the ejection make sure the rounds are not hitting the port and coming out high. If you keep adjusting the ejection pattern lower in this case you will exacerbate the problem. One last adjustment necessary when using extended ejectors is to relieve the ejector on the bottom side so that it does not make contact with the top round in the magazine.

Figure 4 – Tuned ejector

Once you have made these adjustments take the gun out and shoot for a while. Check to see that your brass ejects to the same spot each time (make sure it is not hitting anywhere on the gun on the way out) and, if necessary, make further adjustments.  You will know you have achieved “ejection perfection” when all your brass leaves the gun at the same trajectory in a nice stream. Now you are ready for that next big match.

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