Well, I replaced the BC and the extractor with ones from my 20" upper that has run well for years. I removed the ejector and cleaned the channel up and checked the ejector for burrs, etc.  I put it back together and verified proper ejector operation.  I also polished the chamber with some polishing compound (rhotten stone mixed with oil) on a 38 cal. mop.  With great expectations I went out to the range and ran about 200 rounds through it.  I experienced 2 jams of the extractor dropping the spent case and having it jam up against the locking lugs while the bolt tried to feed a new round.  I called Bushmaster first thing Mon. AM and the fellow on the other end of the line in customer support said it sounded like a gas leak.  He directed me to someone else who will e-mail me an rma # and a prepaid UPS label to send it back in under warranty.  I'm going to include a long letter explaining the problems I am having with it and to hopefully ensure they won't just run 20 or 30 rounds through it and call it "no problem found"  and return the same intermittently malfunctioning upper to me. When inspecting the brass it seems to me I can see a fuzzy ring about 1/4 inch in front of the base of the brass on the brass.  I think I have a chamber problem.  I am going to push for BM to send me a totally new 16" upper.

Could it be a gas leak Tweak??

My brass is all going into a neat little pile at 5 oclock about 5 or 6 feet behind me and to my right.  

Sounds more like extractor/ejector. The shorter barrels tend to need stiffer extractors. A used one out of 20" may not be up to the task.

Why all the work to a brand new upper before firing? You may not want to mention that to BFI as it prolly voids the warranty.

Boog~

I have experienced the same type of ejection issue with my bushy 16' that you described. After talking with Jim at bushmaster and explaining the issue,he seemed to think that the bolt might be shaving small bits of brass from rounds and jamming the ejector. He suggested that I send the bolt back for polishing.
They subsequently emailed me a UPS label and provided me with an RMA.  Since the bolt was sent out just last week, I haven't gotten it back. However, BM's cust serv has been top notch so far.

Good luck!

"Why all the work to a brand new upper before firing? You may not want to mention that to BFI as it prolly voids the warranty."

This is the upper that I mentioned in a previous thread here that was causing me problems about a week ago.  The jamming manifested itself right out of the box and my replacing parts, etc.  were an attempt to isolate the issue.

I will replace all the original parts back into the 16" upper before I ship it back, if I decide too.

Tweak-

you mentioned that a stiffer extractor spring was generally needed for the 16" and shorter barrels.  This place: http://www.sawlesales.com/ is in my neck of the woods and they offer a "heavy duty extractor spring with black insert"  I'm thinking this would be worth a try.  Or maybe one of the extra strength extractor springs offered by Wolf. What are your thoughts about this idea?  I'm hoping I can fix this relatively easily and inexpensively myself without the need to send it off to BFI.  

Boog,

It's easy enough to do and the next logical step. Go with the SAW spring since he's close. Tell Ken that ARf sent ya. If you ask him real nice he might even look the upper over for ya .

Tweak,

Thanks for the "in" with Mr.Elmore.  I'll drop your name and ask real nice, maybe he'll relent and help me out by taking a look at it.  I'm hoping, at the very least, I can stop by and pick the parts I need up without the hassle of ordering online and waiting for the parts to get to my door.   He's so close I'm hoping he'll let me stop on by.  I'm going to give him a call and see what he says.  

Thanks for your help in this matter.

If you wanted to experiment...

I claim an ejector spring that is too strong can aggravate this problem.  Try cutting off two turns from the ejector spring.

If you are ordering/picking up parts get a second extractor and another ejector spring along with the heavy duty extractor spring.

If it were mine, I'd just send it back to BM and let them fix it. Why change parts or mess with a new unit that has a warranty, and maybe void the warranty? Sounds more like an out of spec extractor than anything else.

I purchased a heavy duty extractor spring with the black insert from SAW.  That spring is pretty stiff.  I'm gonna go out and shoot it this weekend and see what happens.  

As far as sending it back in goes, that's probably what'll happen if the new extractor spring doesn't work out.  I just hate to send it back in and be without it if it's something that I can fix relatively easily and inexpensively.

Tweak-  I have been working in Tucson all week and driving back up to Phoenix in the early evening at the end of my days.  Today I finished a little early and got out of Tucson about 345pm and high-tailed it up to Phoenix thinking I could get to SAW by 530pm.  Traffic was a mess and I didn't think I could make it in time.  I didn't even get to SAW untill 10 minutes past their closing time (about 540pm).  The lady who answered the door when I knocked explained that they were not open to the public (I thought they were).  After I explained what I had just gone through to try and get there in time, she asked if there was something she could help me with.  She let me in and took my order for (1) heavy duty extractor spring with black insert.  She went in back and returned with not 1 but 2 heavy duty springs and inserts!  She only let me pay for 1.  I asked her of she was sure and she said "yes".  This lady, I believe she said her name was Tina, went out of her way to make sure I got the part I needed after closing time.   And she gave me a free spring and insert to boot!  Outstanding!  I thanked her for her generosity and her willingness to help me.  What a sweetie she was!  Now I just hope this new stiffer extractor spring works out.  Are stiffer, "heavy duty" extractor springs used as standard equipment now on the shorter barreled M4's??

Tina is Ken's wife. Glad to hear they could help.


ETA, the stiffer black insert spring is standard for rifles and carbines now.

*update*

went to the range today and fired about 250 rounds.  No failures whatsoever.  It appears my extraction problem is gone and the fix was the heavy duty extractor spring and black insert I bought from SAW.

Thanks to Tweak and everyone who responded.

Boog,

Don't forget to write SAW and thank them too. Glad it works now.

Tweak,

Way ahead of you.  I shot Tina off a "thank you" e-mail last nite and already received her response.  I just need to remember to make an appointment next time and they'll be happy to see me.

thanks again.

Excellent on both counts Boog.