Ok,I have been getting failures to eject since I got my new bushmaster.The last thing I tried was leaving the bolt locked back for a day and then shooting,as you suggested.(too much spring tension in a new gun)I went to the range put 2rds in my USGI mag after being told the factory mags were junk.Jamed on the first round(failed to eject).I cleared the jam and fired the last round.The bolt locked back on the empty mag,I looked down and the spent case was just sitting on top of the mag.Two failures in a row.I went back to the fractory mag put 70 rds through it with no problems.Then put 10 rds in the USGI mag and it ran fine.Can a bad mag even cause falures to eject? I'v had jams with both and three different kinds of ammo.I have my leupold red dot sight set now and the JP trigger is working great with the factory springs.Three shot groups were around 1/2in.at 50yds.I'm starting to like this gun but this ejection thing is driving me crazy!I hate to send it back but I'm running out of things to try.Any more suggestions? Thanks for all the help!

Hmmmm..... This post looks familair.

Quoted: Ok,I have been getting failures to eject since I got my new bushmaster.The last thing I tried was leaving the bolt locked back for a day and then shooting,as you suggested.(too much spring tension in a new gun)

No such thing as 'Too Much Spring Tension' unless the spring is FAR out of spec.  Keeing it compressed for a day wouldn't change it a bit.  

I went to the range put 2rds in my USGI mag after being told the factory mags were junk...Any more suggestions? Thanks for all the help!

1) in a Bushmaster 10 round magazines never use more than 9 rounds - then they usually work well.

2) Get more than 1 USGI magazine - many times magazines are 'surplused' because they are bad.  Your magazine could be bad.

In any event magazines usually don't cause ejection problems.  Here is what to look for:

1) clean & lube the rifle with CLP per the -10 (Operators Manual) old.ar15.com/books  While cleaning the ejector check for brass shavings (you will need to remove it).  Make sure the buffer spring is lubricated as well (per the -10).

2) Start on page 91 of the -10 after cleaning to make sure you covered these points.

There is more to try (as listed in the -23&P - also at the above site).  What ammo are you using?  

i had the same problem with my bushy upper. after some experimenting, and a LOT of help here, this is what fixed my problem: extra power extractor spring from wolff gunsprings& an armforte D-fender d-ring.i couldn't get this upper to fire more than 5 rounds without a failure. now the gun runs like a sewing machine.

I'm having similar incidences with mine, but not to that degree.   I'm fairly new here and I hear talk about these D-fender D-rings.   Do they have a website?

thanks

Sounds like a bad(Underpowered) ejector spring.Also, check and make sure the little rubber thing is in there with the extractor spring.

Hey 777, try www.buffertech.com Also, Oly Arms has a similar device of thier own, www.olyarms.com and then click on the USA site version.

Quoted: Sounds like a bad(Underpowered) ejector spring.Also, check and make sure the little rubber thing is in there with the extractor spring.

This is also my vote. You need to focus on your bolt, which contains ejector and its spring. It sounds like the extractor is OK because the case is lying on top of the mag, its already been extracted from the chamber.

Find somebody who knows ARs and get them to look at your bolt.

I'd completely disassemble the Bolt per the TM. As a start you could put the puddle of CLP on the ejector and work it in with a spent casing per the TM...you are using CLP, right?

I've built AR15s and M16s for years and have a little experience in these matters.

The ejector spring contained within the bolt sounds like the culprit to me. You may want to try a bolt from another AR15 and see if that works. That may help you narrow down your problem.

There are two problems with the AR15 bolts. First the extractor spring can fatigue very quickly. In fact on the military's M4, they were changing the springs every 1,500 to 2,000 rounds before they came up with the "O" and "D" rings.

There's still a problem with the ejector spring. It can get sluggish if the spring is weak.  Also, if it's a new gun, there may be some grit in the ejector pin hole which keeps it from giving the proper push.

You should borrow a bolt from someone whose AR15 works first.  If you try to take yours apart and screw it up, Bushmaster may not want to replace it.  If the other bolt works, send your first one back to Bushmaster and I'm sure they'll replace it.

After Eugene Stoner designed the AR15, he designed the Stoner 63.  He was aware of the ejection problems with the extraction and ejection of the AR15.  The Stoner 63 had a knock out type of ejector which was much more reliable.

I just purchase an M96 Recon Carbine from Robinson Armament Co.  They said that it was loosly based on the Stoner 63.  It has the Stoner 63 type ejector. I've fired approximately 3,200 rounds through the gun already without a single failure.  The recoil is less and it just feels better to shoot. The accuracy is about the same as my AR15s.

Quoted: I've built AR15s and M16s for years and have a little experience in these matters. The ejector spring contained within the bolt sounds like the culprit to me. You may want to try a bolt from another AR15 and see if that works. That may help you narrow down your problem. There are two problems with the AR15 bolts. First the extractor spring can fatigue very quickly. In fact on the military's M4, they were changing the springs every 1,500 to 2,000 rounds before they came up with the "O" and "D" rings. There's still a problem with the ejector spring. It can get sluggish if the spring is weak.  Also, if it's a new gun, there may be some grit in the ejector pin hole which keeps it from giving the proper push. You should borrow a bolt from someone whose AR15 works first.  If you try to take yours apart and screw it up, Bushmaster may not want to replace it.  If the other bolt works, send your first one back to Bushmaster and I'm sure they'll replace it. After Eugene Stoner designed the AR15, he designed the Stoner 63.  He was aware of the ejection problems with the extraction and ejection of the AR15.  The Stoner 63 had a knock out type of ejector which was much more reliable. I just purchase an M96 Recon Carbine from Robinson Armament Co.  They said that it was loosly based on the Stoner 63.  It has the Stoner 63 type ejector. I've fired approximately 3,200 rounds through the gun already without a single failure.  The recoil is less and it just feels better to shoot. The accuracy is about the same as my AR15s.

DO NOT follow this idiot's advice!!!!!! Swapping bolts is a cardinal sin, and for very good reason......This moron is setting you up for 2 possibilities: