UPDATE:
Ok I got the little guy to work again.  I think.  I only put 30rds (xm193) through it but so far so good.  I replaced the ejector spring.  The old one was very dirty.  It has some waxy skin hanging off it (CLP residue?).  I also replaced the extractor spring with a Wolf x-power unit.  The Wolf one was a little harder to put in because it was a little longer and much stronger.  I think the real problem is was with the ejector spring as it was just really messy looking.  With the few rounds I shot I noticed the brass was defiantly hitting the brass defector, because the brass was going about 45 degrees forward and to the right, 6ft from the gun when standing.  I also bought a Wolf x-power spring because I thought the bolt might have a little too much rearward velocity but I have not put it in yet.  I look forward to putting a case of wolf through this little AR again.  Thanks for the help all.


Hey.  I am stumped here guys and don’t really know what to do.  I have posted this problem a few times but have gotten nowhere.  So here it is again.  I have a Bushmaster 16” lightweight upper on a Cav arms lower.  I had put maybe 1200rds through it without a hitch.  Now all the sudden the thing is really messed up.  I don’t get it, I have changed nothing but yet the rifle has changed on me.  First off the A2 sights are now mysteriously off at 100yds by over 6”.  I have I have checked all the knobs and adjustments multiple times but they are the same as they were whey I first sighted the gun in over a year ago.  I have re sighted it in but I am clueless why this happened.  Second the gun now jams frequently, on the order of 1 or 2 times per 20rds.  All jams have been failures to eject.  This I also don’t understand this because all parts function as they should as describe in the trouble shooting guide.  The ejector spring is as strong as my other ARs if not stronger as is the extractor spring.  I initially thought it might be short stroking but that can’t be the case because the gun locks back on an empty mag every time.  Also this rifle has loads of recoil; I can feel the buffer slamming the end the receiver extension every time it fires.  What the heck is wrong with this thing?  It shot like a dream for the last year and now it is a peace of crap.      


Bullet in pipe, brass caught by bolt.


Ditto, but brass is fliped.


Bolt locked back on an empty mag and brass just did not fly out.

Yes the same.

first two obvious points that come to mind regarding a shift in point of impact

1. Did you change ammunition?

2. Is your bore/chamber now rusty or pitted or does the crown show any damage?

SoS

No.  Before now this rifle shot any ammo I gave it, but no I have not changed ammo, Wolf an XM 193 most of the time.  The chamber and bore are nice and shiny.

Pivot pin is standered Cav Arms "Speed Pin".  

does the ejector plunger move smoothly?  I ran into similar when I was using really soft brasses ammo (PMP) and the bolt face was covered in shavings that would hinder the ejector plunger from moving freely.

Well the brass goes out stright and only one foot.  My other Ar sends them about 45 degrees to the right and farward and three or four feet out.   I dont think the brass is hitting the deflector any more.  The ejector spring looks and feels fine.  Overfunction... too much gas?  Hmmm...

No markings on the ejection door-portside or the delta ring.  I did a side by side comparison with my other AR with live ammo, slowly working the bolt back after chambering a round and they trew the bullets in the same spot so I really dont see how I could be the extractor or ejector.  I might swap bolts with my other AR that works 100% to see if it is bolt related.  Is it ok to do this?

I need to get some more ammo for testing.  I will try a new ejector spring and see what happens.  I defenatly does have week ejection when firing, 3 feet or less standing up.  An two or four inches at the bench.  It seems so strange though because the bolt I got new from RRA and it has far less round on it that the upper.    

Pop the HG's off and take a look at the area where the gas tube meets the FSB.  IF there is alot of black there, you might be loosing gas pressure there.  Also look at how the FSB is mounted.  Mine uses set screws and they were loose when I got it, maybe it got knocked misaligning the gas port?

I am still thinking ejector plunger though, as even slowly hand cycling mine it launches unspent rounds out about a foot.  

I am pretty new to these guns, so bear with me.

What do your gas rings look like?

Quoted: Quoted: I am pretty to these guns, so bear with me. the guns don't care how look, I'm UAF and mine run fine.

I was PWC...posting without coffee.

I ordered
Ejector spring
Extractor spring wolf x-power
Buffer spring wolf x-power

There is quite a bit of black residue on the gas tube by the front sight.  How much is too much and how can I fix it?  I will try to take a picture of it.  Rember this gun locks back on an empty mag every time.  

Quoted: I ordered Ejector spring Extractor spring wolf x-power Buffer spring wolf x-power There is quite a bit of black residue on the gas tube by the front sight.  How much is too much and how can I fix it?  I will try to take a picture of it.  Rember this gun locks back on an empty mag every time.

Swapping out the ejector and extractor spring is good, but I would hold off on the XP action (buffer) spring.  Depending on what's going on, a heavier action spring can actually make matters worse.  

Ya I will hold off on installing the x-power buffer spring.

Here is a pic of the gas deposits on the gas tube.  Littel messed up AR on left, fine bigger AR on right.  

any  new updates on this problem?