AR15 ejection/extraction problems :(

[wally]

I'm sure this has been discussed before, but I couldn't cone up with the right mojo for the search function to return anything useful


CAR4 was working fine when all of a sudden I started getting extraction failures. Didn't take long to realize the extractor had broke -- split at both holes where the pin goes thru.

No biggie, got a new extractor and spring at the next gunshow and replaced it. Problem is still got extraction failures

Put back the original spring, now it extracts but is very unreliable in ejecting the empties.

Swapped bolt and carrier with one of my full size guns and the problem switched, CAR4 functioned fine, full size now has ejection failures.

Can't see or feel any difference between the ejectors on the two bolts. If there is a problem with the replacement hook it sure can't be a difference I can see with an 8X loupe

The only thing that feels different is the gas seal rings on the non-working bolt are noticably "looser" than those on the working bolt. I thought if these are worn out the gun will short cycle, it appears that a new round is stripped from the mag on every ejection failure. The CAR4 is my AR with by far the highest round count so while I'd be dissapointed if these seals have a rather short life, but they could be fine and just the difference between normal wear at a few hundred rounds vs. maybe 1000 rounds.

Any suggestions?

--wally.

 

[TechBrute]

You may want to try a new ejector, pin and spring. The tolerences in the bolt are pretty close, so you may not be able to visually see the difference. I think your troubleshooting has pretty much narrowed it down to that part being a problem.

I had a bolt catch that was giving me problems. It came new in a LPK, and I figured it couldn't be the part. Well, once I swapped it for another one, it worked perfectly. I couldn't visually tell the difference, but I got out some calipers and sure enough the problem catch was not as wide and therefore was jamming into the bottom of the bolt instead of holding it back.

 

[wally]

Thanks for the suggestion. Got a few empties out of the range bag and slipping them over the extractor makes it look like the replacement hook is a little closer to the bolt face, more obvious is that the back side of the extractor "notch" is noticably below the bolt face, probably not enough room reliably slip over into the extraction groove. Using some small allen wrenches as "feeler gauges" the gap between the hook and bold face on the working bolt/extractor combo is clearly wider than that on the unreliable pair.

So if these tolerences are so tight, can I trust ordering a replacement from bushmaster or should I wait for the next gunshow and bring my bolt and pin in to check the fit? I now have a "gauge" to test with

As an exercise in "survival gunsmithing" I'll see if I can file the hook face to move it forward enough to get it going again while I wait for a new extractor. I'm going to pick up some gas rings too just to have on hand, as they are pretty cheap. OTOH replacing them looks like a royal PITA unless some obvious trick jumps out at me when I see the virgin replacements

--wally.

 

[TechBrute]

The accepted practice is to keep an extra bolt assembly in your kit. You can reconstruct the broken bolt in the comfort of your shop. In the field, 60 seconds to a new bolt.

 

[wally]

I've always bought either complete guns or uppers with bolt assemblies.

IF tolerences can stack up and cause a simple extractor replacement to not work, I'd worry about headspace issues with random bolt assembly and random upper.

I'd enough confidence that they mostly interchange that I was willing to swap bolt/carriers between guns and fire a few rounds to troubleshoot., but each is going back into the gun it came with now that the test is complete, just to play it safe.

Having a second gun is much faster than the 60 seconds you may never have

The "old saying" that I'd take to heart is: "if you need a gun, carry two, if you don't carry a .25". Nowdays I substitute a Kel-Tec P3AT for the .25ACP , technology marches on.

--wally.

 

[TechBrute]

Wally, please don't take this as a flame, but your post doesn't make sense in a lot of places.

IF tolerences can stack up and cause a simple extractor replacement to not work, I'd worry about headspace issues with random bolt assembly and random upper.

It has to do with an out-of-spec part, not stacking tolerences. Also, the headspacing is handled in the barrel extension, not the upper to bolt fit. As long as your bolt is in spec and your barrel extension is installed properly, headspace is not an issue.

I've always bought either complete guns or uppers with bolt assemblies.

This doesn't address the issue here, because when you buy an upper with a bolt, there's somebody just grabbing "in-spec" bolts and tossing them into the uppers.

This all boils down to having access to parts that are in-spec.

Having a second gun is much faster than the 60 seconds you may never have

I'm not sure who carries around a second AR just because a small part might break, but to each their own.

 

[Rexrider]

Here are two suggestions for you that may help with extraction.

1. Go to a hardware store and buy a pack of #60 o-rings. They just so happen to fit perfectly over the spring on the extractor. The o-ring will tighten up the pressure on the extractor.

2. Purchase a wolff extractor spring. Does the same thing as number 1.

It is no uncommon for the extractor spring to be too weak to allow for consistent extraction. A lot of people use the 0-ring trick to clean up extraction issues. Not to mention it is a very cheap fix to try.

If the 0-ring fixes the problem then buy the Wolff spring as a permanent solution (although some people just use the o-ring)

Unfortunately, you can't always know if the parts you buy at a gun show are quality parts.

I seriously doubt the gas rings are worn out after 1k rounds. An easy way to test short stroking is to have 1 round in the mag. If the bolt locks back then you are not short stroking.

Just something to try. Good luck

(edited for spelling)

 

[wally]

How'd I know I didn't have an out of spec bolt as a spare?

Hopefully that "somebody else" has tools to gauge that the barrel and bolt is in spec before putting them together and shipping it off to me. Possibly wishful thinking, but on any mass-market item bad ones that shouldn't have been sold end up on the market. That's why there are warrenties.

Traditionally the second gun is a handgun. Admitedly a tough choice, extra ammo for the rifle or a handgun in case the rifle breaks. Not sure what I'd do if the SHTF, would come down to gut instincts and how much I saw it coming, some folks see it coming soon.

OTOH, I always have a second gun at the range

I doubt the guy intensionally is selling bad parts, about the same price as I'd order from Bushmaster minus S&H which would pay for my gun show entrance fee He's been at most every decent sized show for a long time and I'm sure he'd exchange it, but I prefer to test my SHTF skills and pretend I had to make the only extractor I could get my hands on work. $12 is not an expensive project, although there is not a lot of extra metal to work with, I'd like to test myself while waiting for a replacement. A few more ejection/extraction failures won't do any harm and I might learn something that comes in handy some day

--wally.


Edit:

Rexrider, prettry sure I got an out of spec extractor. Comparing the hook ends under magnification I couldn't see any difference. Probing the relationship between the hood end and the bolt face, the unreliable one has a smaller gap -- looks like the pin holes might be a bit too far forward pulling the hook too close to the bolt face to reliably drop into the groove. A stronger spring made matters worse -- usually leaving an empty in the chamber same as the broken one did, the weaker original spring seems to extract but they don't stay on the hook long enough to reliabley eject -- about one in three would jam on average, getting caught between the carrier and the port opening . The ones that did eject were really easy to find laying about three feet to my side, would be a great feature for reloaders if it was reliable

 

[Southern Raider]

It is not entirely uncommon for some small brass shavings to work themselves into the ejector hole. Sounds like you'll need to knock out the retaining pin and check it out. Check the extractor force as well.

 

[wally]

First thing I checked was force and smoothness of the ejector between working and not working bolts. Hard to see how the trouble could lie here. But its the next thing I'll check if an in spec extractor is not the cure.

There is a mesurable difference in the extractor hook and bolt face relationship between the working and not working bolt/carrier assemblies. I've ordered a replacement and plan to hack on the duff extractor to verify my diagnosis -- assuming that moving the hook face forward a few thousandths still leaves enough metal to not break off on the first couple of shots.

--wally.

Edit:
Anybody got a trick on how to replace the gas rings -- don't thing I need to, but it sure doesn't look obvious how to get the old ones off.

 

[Morgan]

Make certain the key is tight. I've only had one problem with extraction, and that was it.

 

[Bartholomew Roberts]

I'm not familiar with who makes the "CAR4" AR15-style rifle. Do you know what parts were used with it? Specifically, do you know whether your barrel has a .223 SAAMI chamber, 5.56 NATO chamber or something in between?

Extractors and other parts can break and wear out even in relatively new factory Colts; but an extractor breaking and then issues within 1,000 rounds or so sounds like bad parts somewhere in the gun. Either higher than normal pressures are cycling the bolt very violently, or the bolt is a reject from someone else.

I've got 7,800rds on my high round count bolt (Bushmaster) and everything is still running well with it, though I did replace the extractor spring as part of routine preventative maintenance around the 6,000rd mark. The rest is all original.

What type of use have you been giving the rifle? Any suppressor or full-auto usage? Are you using 5.56mm? Military surplus? You say the rifle is failing to eject - do you mean that the round is extracting but not ejecting or that the extractor is slipping off the brass? Is there a noticeable "bite" in the rim of the fired case?

 

[wally]

At this point I still believe the only problem is the original extractor broke and I had the misfortune of getting an out of spec replacement. The "gap" between the extractor hook face and the bolt face is significantly narrower than is the one on the bolt carrier from my full size AR that I swapped to isolate the problem.

Extraction happens, but ejection is very weak with about one in three not clearing the port and getting trapped as the next round attempts to chamber.

I've shot a variety of USA, UMC, Wolf (some old Lacquer, some new polymer) LC surplus, IMI surplus, Federal SS109 surplus, Olympic SS109. After replacing the extractor I've only tried LC, IMI and Wolf polymer, brand of ammo had no effect, all worked with the original extractor until it broke, the three I tested the replacement with all failed.

I've ordered a new extractor from Bushmaster and I'll followup after I've tried it.

No evidence of loose or leaking gas key. Last round locks the bolt back, sometimes the last shot empty is just laying in the port when the bolt locks back.

--wally.

 

[Bartholomew Roberts]

At a minimum, it sounds like it is time to drive the pin out to the spring loaded ejector and clean that area. You may also want to replace that spring while you are in there as a precautionary measure.

However, if you want to try narrowing it down to extractor or ejector, just swap ONLY the extractor from the bolt that works and see if the problem reproduces.

 

[wally]

SHTF gunsmithing skill test succes!

As I said earlier in this discussion I filed the "hook" face of the duff replacement extractor to move it forward so the small allen wrench I was using as a feeler gauge would fit bettween it and the bolt face.

Got a chance to test my work this afternoon. Shot 40 rounds of Wolf with no failures. Ejection was about what I remember, empties flying 6-8 feet 2 o'clock (muzzle is noon). Before the mod, it was rare to go three shots without an ejection failure and rounds that did eject left the cases at arms length -- I guess the gap just was't quite wide enough to always slip over into the extraction groove.

Doubt it'll hold up as well as an in spec one would, but it was a gratifing test. I'm greatful for all the helpful advice in this discussion. I'll keep the one I ordered from Bushmaster in the range bag and probably leave this one in to see how it holds up to continue the exercise in "survival gunsmithing".

--wally.

 

[TechBrute]

Good job. You never learn anything until you tear it down and look at it.

 

[wally]

Put another 60 rounds thru it today, no problems.

Bushmaster still hasn't shipped my replacement extractor

--wally.