Firearms

AR-15 Tech: Extraction and Ejection Tips and Tricks

AR-15 bolt face

I recently inked an article for these pages on the AR-15 bolt assembly—all the pieces-parts, watch for it over the next couple of weeks. Two of those pieces-parts can be problematic, especially with particular AR-15 platforms. Extractors. Ejectors.

AR-15 bolt showing how a cartridge case is ejected
Here’s what an ejector is supposed to do, and all it’s supposed to do: present the case so bolt rotation and travel puts it out the port. If it hits too hard (more common than too light) cases can get bent and kicked to the netherworld. I tune them (cut the spring) on guns I shoot a lot.

This article is a combination of set-up and troubleshooting topics, and the general idea is that if the set up is done right there’s no troubles to shoot.

Basics: The extractor and ejector team up to get a spent case out of an AR-15.

If spent cases are not being successfully expelled, the first step is to figure out which piece is at fault. We’ll cover that later in this article. First, we to lay some groundwork.

Extractor Tech

The extractor is essentially a spring-loaded claw that snaps over and into the rim of the cartridge case. Its job is to pull a fired case out of the chamber.

One extreme symptom of faulty extraction is that the gun fires and the bolt comes back, and the case is still in the chamber. What’s happened there is that the extractor lost its grip on the rim. Or, perhaps, the case reluctantly released but the extra drag slowed the carrier progress to the point it didn’t make a strong enough run to complete the cycle (and the case didn’t eject). More extreme: the case stays in the chamber and there’s a chunk missing from its rim!

AR-15 bolt and springs
An extra-power spring, or effectively increasing spring pressure through adding a “booster” insert, will help prevent the extractor slipping slap off (and out) of the case rim groove. The inserts do the most. Don’t run a combination! If extractor tension gets too high, it doesn’t hurt extraction, but it hammers the case head as the round is chambered. That’s an accuracy issue, not a function issue.

Overall, extraction problems are common and that’s because of the additional stresses within the gas operating system in some platforms. This article isn’t about those problems, but it is… Lemmeesplain: “shorter” gas systems, such as on carbine- and pistol-length barrels, along with the (increasingly) higher-pressure 5.56 NATO-spec ammo common now, create overly-quick function.

If the bolt unlocks too soon, the extractor tries to yank the case out of the chamber before it’s ready to leave. The case is then kind of an immovable object because it’s still somewhat expanded and gripping the chamber walls. Keep (always) in mind that AR-15 gas operation points of progress are measured in milliseconds. In this instance, we’re talking about fractional milliseconds. So, this is, and isn’t, the fault of the extractor.

.223 cartridge case with a bent rim from a bad extractor
Here’s a clue! If you see bent rims, take a look at the chamber. If the extractor simply lost its grip on the case rim, then a tensioning trick is likely to solve your problems. Ultimately, taming the system operation cures all.

The real solution to solving extraction issues is in delaying bolt unlocking, and that’s a main function of increased-mass buffers and stouter buffer springs. Ultimately, the cure is reducing the level of gas pressure in the system, and that’s another article, or three, entirely.

However, increasing extractor pressure (so it holds tighter to the case rim) is about the only answer to getting some guns to work. I recommend this mod from the get-go on any carbine or pistol.

The fix is easy enough—either a stouter spring or a “booster” insert. Many bolts now feature both, and it’s an easy enough DYI to retro-fix.

That being said, the first suggestion I have is to make sure the chamber is clean! To that end, I clean my chamber each time I return from the range, whether I do the whole barrel or not. I also polish the chamber on a new build. This is not difficult, given the right tool set. What about a dirty chamber or rough chamber? Honestly, no matter how much extractor grip there is, that’s problematic and needs to be fixed first.

Flex-Hone oil can
Before that, I polish all the chambers in all my guns. I use a cylinder-hone-style attachment for an electric drill, also .357 (this is made to polish revolver cylinders). Doesn’t have to be a mirror, just not rough. There will be tool marks left from the chambering reamer, get those gone.

I talked about extractors first because, clearly, it’s not always the ejector’s fault if a case doesn’t clear out. So, next is what to do when it’s not the extractor’s fault.

Ejector Tech

The ejector is a spring-loaded plunger housed in the bolt face that bears pressure against the left side (shooter perspective) of the cartridge case base. Its one and only job is to tilt the spent case toward the right, toward the ejection port, so that bolt rotation and rearward movement can pitch the case on out into the wild blue yonder.

The good news is that, usually, there’s plenty of “spring.” A failure to eject usually is caused by too much spring! If the push is too hard, too soon, the case can crank around excessively and stay in the upper. Ejector over-function is usually the culprit if there’s something jinky going on with spent case condition, like dents and creases (from hitting off the receiver). Wildly spinning, careening spent cases, especially those landing nilly-willy, are the result of the ejector pushing too hard too soon. We can fix that right quick like and in a hurry.

nylon chamber brush for .357 caliber
Clean your chamber! It’s not hard. Use a stiff nylon bristle .357-cal. brush and then wrap a patch around it to finish up. Do this each and every time you get back from the range.

Fix it by shortening the spring. I use a cut-off wheel in a hand-grinder.

Too little pressure can also keep the case encased in the upper because there’s not enough angle created to head it out of the port. That fix is also easy. Get a new spring—and get a better spring while you’re at it.

There’s another level to this that most won’t benefit from (much), but for a gun that’s fired a lot at a shooting range, tuning the ejector is possible, and worthwhile. The main effect and reason is to influence the location of the landing place for spent cases, and the distance they fly to get there. As said, a standard ejector spring is almost always capable well beyond the task required of it. Too stout.

To tune ejection, cut coils. For a competition gun, I start the trials at an (trimmed) overall ejector spring length of 0.800 inch. That’s usually a big improvement. I also replace it with a Chrome Silicon spring, which is also an “extra-power” piece, but mostly because these last literally for the life of the gun. Don’t start too short, and, as insinuated, you might not want to start at the figure I gave for a standard spring. If there’s not enough power pushing the ejector against the case head, the case can stay inside the upper.

Bolt vise with AR-15 bolt locked in
Here’s my suggested extractor trick. Chrome-silicon spring from Wilson Combat. Extra power and lifetime correct tension. Go ahead and get the chrome-silicon ejector spring in the package too. Oh, and get a bolt vise! Sho makes this easier.

There are differences in what I’ll do to a gun that’s used for fun next to one that’s used otherwise, and “otherwise” means that it might, along with its operator, be faced with a circumstance where a malfunction influences his or her capacity to cycle oxygen. That extends to gas system setup, trigger tuning, and a few other range-day tricks that make for a better behaved AR-15 but might limit its absolute capacity for 100 percent function.

Last

However this might sound, also make sure you have an ejector spring installed behind your ejector! They can, and have, been confused with detent springs. Likewise, I’ve heard tell of trigger disconnector springs being mistakenly installed under extractors. They too look similar.

Have you ever had an issue with an AR-15 not extracting and ejecting the cartridge case? What ended up being the culprit? How did you fix it? Share your answer or any other tips in the comment section.


This article is a specially adapted excerpt from Glen’s latest book: America’s Gun: The Practical AR15. Click to visit the Zediker Publishing website.

About

Glen Zediker is the owner of Zediker Publishing, and specializes in books and other publications focused primarily on AR-15s and Handloading. Glen has worked professionally with some of the greatest shooters on the planet, as well as leading industry “insiders.” And he does pretty well on his own. Glen is a card-carrying NRA High Master and earned that classification in NRA High Power Rifle using an AR-15 Service Rifle. Visit http://www.ZedikerPublishing.com and learn more, plus articles for download.

The Mission of Cheaper Than Dirt!'s blog. "The Shooter's Log", is to provide information - not opinions - to our customers and the shooting community. We want you, our readers, to be able to make informed decicions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (7)

  1. Had serious failure to extract in an LR308. Empty case wouldn’t budge. Found a large burr at the front edge of the neck portion of the chamber. I found I could clear it by pounding the butt on hard surface while pulling on the charge handle. Sent the barrel back to the maker.

  2. I have shot 1000s of 223/556 rounds in several ARs I built.And the one constant is with steel casing ammo.The casing would get stuck from expansion and I would have to use my cleaning rod to get it out.

  3. Great article I’ve never really thought about extraction quite like that but I will say Ive never had any problems either. I do have all 4 gas lengths as well so I guess Ive been lucky. Anyways thanks for the great article!

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