AR-15 extractor spring

[SADshooter]

I've got a Bushmaster carbine upper on a Colt lower. Recently experienced several failures to extract during a range trip after not firing the rifle for a while. After clearing the second round fed into the rear of the fired case, cases would extract withmanual cycling.

I had problems after purchase with this upper because the gas port was out of spec, but that was corrected. I've got 3-500 rounds out of this upper.

I've thoroughly cleaned the chamber (I think) since, and on disassembling the bolt, the extractor rim appears OK, but the extractor spring looks a bit mashed (I can see two coils, and they don't seem symmetrical). Is there a visual or "feel" test for this spring? I'll probably replace it just on principle, but I'd like to tap the knowledge base here.

Thanks.

 

[Steve Smith]

First, check under the extractor lip to see if there's something under it. After that, sure, replace the spring and extractor...why not, they're cheap.

 

[AR-10]

I just checked the spring on two of my Bushy uppers.

If you take the bolt apart and measure the amount of spring sticking up out of the extractor, it should measure just a smidge more than one eigth of an inch to the top of the spring. Best I could do with a 25' tape measure.

You did not say what brand of ammo you are shooting. That may make a difference. I usually shoot M193 equivalent loads with mine, and I have found that with carbines and hot ammo, you need to beef up the extractor spring a little. Wolfe extra power springs might work. I have been running a small O-ring placed over the factory extractor spring on my uppers, and it has helped quite a bit. There is also the Defender insert that will do the same job, for about two hundred times the cost of the little O-rings I use.

 

[Steve Smith]

With regards to AR-10, I do not believe that any extra power springs, o rings, or anything else should be required to make your rifle work. Out of perhaps a few thousand Highpower shooters that I correspond with in one way or another, I know of no one using any of those items. Of course, we all use stout ammo, but that can exacerbate, rather than alieve the problem if your extractor is weak.

 

[AR-10]

I agree with Steve that these things should not be needed to provide proper function.

Just telling you what I did to make my carbines function reliably.

Colt recognizes that carbine uppers are a little more rambunctious than rifle uppers. They provide stiffer extractor springs (with a black nylon insert to designate the stiffer spring) on some of their uppers because of that.

A carbine upper has a shorter route for the gas to travel that unlocks the bolt. This can cause the bolt to start moving before the spent brass has shrunk enough to unstick from the chamber wall.

If the gas port in the barrel is a smidge oversized, that would add to the problem.

Another product on the market to address the short gas path is a Fat Boy gas tube, made by Precision Reflex Inc. It is a carbine length gas tube that has the same internal volume as a rifle length gas tube.

 

[SADshooter]

Thanks, gents!

 

[Kharn]

SADshooter:
Are you sure you dont have a disconnector spring in place of the extractor spring? They're very close in length and thickness to each other, but the extractor spring has the same diameter over its entire length while the disconnector spring is larger in diameter at one end (so that its held in place by the trigger). A disconnector spring wouldnt work quite right in the extractor, while an extractor spring could probably function in the trigger/disconnector.

IIRC, An easy way to check this is to punch out the pin holding your trigger and disconnector in, remove the disconnector and see what the spring does. If it refuses to be removed from the trigger without some pulling, its the proper spring. If it flies off into the wild blue yonder, it was the extractor spring.

Also, check to see if the little black plastic/rubber thing is present in the bolt assembly, it goes between the bolt and the extractor spring (and partially up into the extractor spring). Its absence will cause FTExtracts when the extractor jumps over the cartridge rim (the rubber thing works to prevent the extractor from opening that far).

If all else fails, get an extractor D-ring or other such device to give the extractor some force to it. The D-ring works like the rubber thing from inside the spring, but goes around the outside. If a D-ring doesnt fix your extraction problems, your rifle definitely has some issues.

Kharn

 

[BDM]

Never had any problems with the extraction in the 11 years ive had my pre bushy carbine all I did was is to replace the spring to the stiffer one wich was actualy specified in the original M16 design but the had to go to a less stregnth spring because case heads were being ripped off wich was due to chambers not being chromed at the time so the powerful spring was killing the empty,for comfort I replaced to an xpower spring same insert and I use a hard chromed extractor because I use a lot of wolf and this combination seems more reliable with steel case,ther is also a company called LMT and also knights that have redesigned the bolt/carrier group double spring extractor bolt chromed on inside reinforced front of carrier and another gas vent hole on side of carrier,now 3 to take care of the chamber pressure on extraction so a new tube or port modification is not necessary the LMT bolts lugs are redesigned as well as knights but with knights there are 2 versions 1 thgat works with the current barrel extension and 2 that needs a new extension because the lugs are rounde the LMT bolt is chromed inside and electrolosis nickel on the out side they claim its just as good as chrome but a thinner coating,I saw pictures on AR15.com on the uppers,barrels assemblies section its under the thread sopmod2 upgrade.