Ejection problems on my AR15

[Julien Boit]

Hey all,

I'm back with my trouble with this bloody M4 carbine !

Last time I changed the regular ejector spring for a wollff extra power from Brownells.

I loaded a 20 round mag with military surplus 62 grs, fired it without a jam.

Then, I lend it to my brother who fired one round, then nothing : No extraction !

Let's take the cleaning rod and eject the case, reload and then again : No extraction.

It happened four times.

I then decided to clean the barrel and it worked.

I cleaned the barrel between each mag.

This way the rifle work but I don't want to do that each time I shot a mag.

What can I do ?

Thanks

DVC

Julien :-)

(Edited by Julien Boit at 7:59 am on Dec. 26, 2002)

[Tombstone Tactical]

You said ejector spring was changed, but then said no extraction.

If I understand you, after firing a few rounds, It will leave an empty case in the chamber.

1. does the extractor pull and leave damage on the rim?

If so ck that the hook has a full grab around the rim.

sometimes junk gets under the extractor and won't let it reset down in contact with the bolt.  Is the hook flat on the back side?

Or rounded?

2. too much head space can cause gases to fowl the chamber in a short time. causing to much case to chamber friction.

3. is the gas system clean?

Good luck, TT

[David Benzick]

Sometimes the chamber isn't cut as smooth as it should be.  Here's a trick I got from Bennie Cooley.  Wrap an AR chamber brush with 000 steel wool.  Mount the cleaning rod in hand drill and polish the tool marks off.  This solved the problem for me.

Good luck.

[Julien Boit]

TT:

The extractor is in good shape, no dirt at all, I cleaned the bolt  when I installed the spring, everything was Okay ,so do the gas system.

The case is damaged on the rim when it's not extracted.

It happens more frequently with 62 grs portuguese military surplus.

It happens too with NGA 55s but less frequently.

I have no gauge to check for the headspace.

One thing that's strange is that the rifle works great with reloaded ammunition with "soft" charge .

Could this be a clue ?

David:

Thanks for this advice, i'll give a try.

DVC

Julien

:-)

[EricW]

"One thing that's strange is that the rifle works great with reloaded ammunition with "soft" charge .

Could this be a clue?"

Yep, it sure is...  Your extractor is clearly working properly.  I'm guessing chamber finish is the culprit.  Do you have a chrome-lined barrel on that M4?  If so, I'm not sure if the steel wool trick or any other polish will help.  If not chrome-lined, try some Flitz or Wenol polish too.  That might help clean it up.

E

[Tombstone Tactical]

The chamber is the direction I would go In. Mil. spec rds. tend to be a little hot and fast. Brass tends to be harder, after the presure peak the brass is slower to relax. Also the 16" gas system is drilled .018-.028 larger then the 20". the bolt is trying to go back before the brass has relaxed. Have a qualified Gunsmith ck and or polish your chamber. You don't wan't a hack to do it.

Happy New Year: TT

[Julien Boit]

Eric:

The barrel is not chrome lined, I'll give a try for the polishing tips.

Thank you all for the advices.

I'll let you know about the results.

DVC

Julien

[Carlos]

Non-chromed chamber? You are in luck! Do a search on US google.com on Varmint Al's reloading and check out his page on plishing chambers w/ Flitz polish.  It does not take a meaningful amount of metal off (read it will NOT make your chamber larger to any meaningful degree) but it will smooth it out. Feel free to disagree, top experts do not agree, but I agree w/ Al that chamber walls are not meant to be high friction devices. Let us know what you discover.

[BPiatt]

At first it sounded like you were shooting the laquered covered cases, common on the imported surplus ammo.  That stuff will shoot ok but the laquer will stay in the chamber.  If you keep the gun hot, there usually won't be a problem.  Once the gun cools down and you try to shoot again, the laquer is now sticky and will cause problems.  

If you're not using it, then it just may be your chamber.  You can follow the instructions that the other posts say but you can learn a lot about your chamber by inspecting your shot brass.  See how smooth some of your brass is.

If your chamber work doesn't fix the problem, I'd look into how much gas is flowing to the bolt carrier.   Too much gas can cause the problems you described.   Your gunsmith can check the gas port holes and alignment.  If all looks good, you may need an adjustable gas block.

Good luck,

Bruce