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Discussion Starter · #1 ·
So I built this gun a couple of years ago and never had any problems until now. I am running a 16" ARP barrel and an ARP superbolt.
Recently I took the gun apart to lap the upper receiver to make sure it was square; and then put it back together.

At the range Saturday I started having what I can only describe as "failure to eject" malfunctions. Brass would be fully extracted from the chamber, but would remain in the upper receiver oriented 180 degrees, so that the case mouth was facing the bolt / rear of the gun. Each time this happened, I took out the BCG, inspected everything, wiped everything down and re-lubed the gun.

These malfunctions seemed to be totally random, not dependent on which kind of ammunition I was using or which magazine was in the gun. Out of 30 rounds or so, I experienced the malfunction probably 5 or 6 times.

Any ideas?

In better news, on the same range trip, I managed to shoot this group at 200yards using Hornady 110g BTHP ammo. By far the best group I have ever shot at 200 yards with any gun ever.
I know the black pasters make it look like I might have faked this ... so you'll just need to trust me that I didn't.
 

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Weak ejector or dirty with brass shavings around and inside the ejector hole.


Sent from a final firing position, the crosshairs are on you!
 

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Weak ejector or dirty with brass shavings around and inside the ejector hole.

Sent from a final firing position, the crosshairs are on you!
Agree! Early on had failure to eject, was leaving empty brass in upper. Turned out to be dirty/sticking ejector.
 

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Discussion Starter · #5 ·
Thanks, guys. I'll take the bolt apart and see what I can see.
 

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The little 1/16" hole on the side of the bolt is to oil the ejector. You can push the ejector in with a screw driver then let the ejt pop out several times. They need a little break in like everything else.
 

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Discussion Starter · #8 ·
Thanks for all of the advice.

I took the bolt apart, and there was a lot of brass in the ejector channel. I cleaned everything up and lubricated the ejector / spring a bit. We will see if that makes a difference.
 

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Thanks for all of the advice.

I took the bolt apart, and there was a lot of brass in the ejector channel. I cleaned everything up and lubricated the ejector / spring a bit. We will see if that makes a difference.
If the ejector is flat and sharp around the edge? You can sand that sharp edge off (just enough so the ejector doesn't shave the brass) and that should help. I use a drill motor to spin the pin and sand paper to round the radius. It don't take much to round the radius and avoid removing anything off the top of the pin.
 

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I built a AR308. first AR. I went round and round with FTE. But I didn't know enough to to know what was actually happening. I chased my tail with a butt load of good advice on "cycling issues". Anyway, it was failure to eject. Ejector and spring was fine. The case actually slips off the weak extractor. I had a JP enhanced bolt and JP redesigned their 308 extractors because they were too weak. They changed their profile and gave stronger springs.

Not that you have a 308, but just to add.... BCM has a stronger extractor spring and o-ring kit. I use them on all my stuff now. Springco/Tactical springs has a kit as well, their spring is more stout that the BCM. They have many more "extra power" springs. I like their stuff.

Anyway, sounds like you got it handled with everyone's spot on advice. I know you don't need King Kong strength springs to run a AR. After all my problems though, I do run stronger extractor springs and have a couple spares on hand.
 

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I built a AR308. first AR. I went round and round with FTE. But I didn't know enough to to know what was actually happening. I chased my tail with a butt load of good advice on "cycling issues". Anyway, it was failure to eject. Ejector and spring was fine. The case actually slips off the weak extractor. I had a JP enhanced bolt and JP redesigned their 308 extractors because they were too weak. They changed their profile and gave stronger springs.

Not that you have a 308, but just to add.... BCM has a stronger extractor spring and o-ring kit. I use them on all my stuff now. Springco/Tactical springs has a kit as well, their spring is more stout that the BCM. They have many more "extra power" springs. I like their stuff.

Anyway, sounds like you got it handled with everyone's spot on advice. I know you don't need King Kong strength springs to run a AR. After all my problems though, I do run stronger extractor springs and have a couple spares on hand.
too stiff isnt good either. i have solved issues by removing O-rings.
 

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too stiff isnt good either. i have solved issues by removing O-rings.
Me too. In cold weather the O ring doesn't compress very well either and causes issues. you may have to try a lot of things to see what the problem is.
 
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