6920 - normal brass wear?

[clandestine]

Brass can sometimes impact that area on some ARs. Ive seen it even with shell deflectors. It hits the deflector and continues spinning like a gymnast doing backflips and hits the lower. Several things can cause this but mostly its a bad ejector or ejector spring.

I cannot verify this is happening with that photo though. I would have to see it in person.

To test the theory tape an ink pad to the gun. And fire off. If you see ink kisses on the brass the. The casings are doing it. If not the. Something in the case, a sling, or a cleaning vise is doing it.

 

[nyu04]

I don't see how a case could have impacted that area after ejection without bouncing back off of something and coming back towards the shooter. It looks like the rifle could have scraped against something. You said the scratches are all in the same direction, right? Sounds like the rifle brushed up against something or was placed on its side on an abrasive surface.

Another thing is that the scratches look to be at vertical angle, not horizontal. Ejecting brass would make a horizontal mark, not vertical. Also, there are no marks on the selector or takedown pin. It looks like the scratches could have been done before the lower was assembled. I'm betting this was the case and you just didn't notice until now.

Plus, if they are just brass scratches they should be able to be brushed off with a nylon brush and CLP.

Dude - thanks for the pointer. I used a nylon brush and CLP - marks did not come off. As a matter of fact, they are slightly indented into the receiver.

Are you wearing a ring on your index finger....bet that's it when you keep your finger off the trig. Otherwise no clue.

No ring on index finger. Only my wedding band but it's on my left hand

Brass can sometimes impact that area on some ARs. Ive seen it even with shell deflectors. It hits the deflector and continues spinning like a gymnast doing backflips and hits the lower. Several things can cause this but mostly its a bad ejector or ejector spring.

I cannot verify this is happening with that photo though. I would have to see it in person.

To test the theory tape an ink pad to the gun. And fire off. If you see ink kisses on the brass the. The casings are doing it. If not the. Something in the case, a sling, or a cleaning vise is doing it.

Great idea with the ink pad, bud. I won't have access to the farm for a while so I may just give Colt a call Monday to see what they say. Then do my own testing if they said it's "normal".

Like I've said, I don't even mind the marks - just want to make sure the rifle is functioning properly. Thanks all for your ideas/comments. Will update this as I find out more.

 

[clandestine]

WipeOut Bore Foam will remove any brass kisses. If the anodizing is cimpromised you can use Birchwood Casey Aluminum Black to darken any silver spots.

 

[Broder]

I don't think those marks are from ejected brass. They were most likely there before and you just didn't see them or they were caused by something else.

 

[bkuether]

Brass can sometimes impact that area on some ARs. Ive seen it even with shell deflectors. It hits the deflector and continues spinning like a gymnast doing backflips and hits the lower. Several things can cause this but mostly its a bad ejector or ejector spring.

I cannot verify this is happening with that photo though. I would have to see it in person.

To test the theory tape an ink pad to the gun. And fire off. If you see ink kisses on the brass the. The casings are doing it. If not the. Something in the case, a sling, or a cleaning vise is doing it.

I buy a left handed AR and EVERYONE asks me, WHY? Just shoot the right handed AR... it has a DEFLECTOR.... Now I KNOW I made the right decision...... If this AR is doing a double bounce off the side of the rifle, where do you think they go next if you are shooting left handed? THANKYOUSTAGTHANKYOUSTAGTHANKYOUSTAG.

My guess is these marks are from a rub. Ring, or something else scratched it. Brass flying/tumbling backwards will keep going backwards even if just now and again. Some of these shell casings would end up behind the shooter or even in his lap.

 

[clandestine]

I buy a left handed AR and EVERYONE asks me, WHY? Just shoot the right handed AR... it has a DEFLECTOR.... Now I KNOW I made the right decision...... If this AR is doing a double bounce off the side of the rifle, where do you think they go next if you are shooting left handed? THANKYOUSTAGTHANKYOUSTAGTHANKYOUSTAG.

My guess is these marks are from a rub. Ring, or something else scratched it. Brass flying/tumbling backwards will keep going backwards even if just now and again. Some of these shell casings would end up behind the shooter or even in his lap.

Its not common and it CAN be corrected. I shoot left hand just as often as I do right hand when testing AR's I service, and my personal AR's. Left Hand AR's are not necessary.

 

[smores]

To back up what chad said, check this out:



The brass is hitting the back edge of the ejection port (at the base of the deflector, you can see the anodizing wearing) before the brass hits the outermost edge. ..



Before wrapping around the rear of the deflector. I run this 11.5" upper with an H2 buffer, but also run it suppressed without changing any components, to test reliability in "field" conditions. I have a dedicated suppressed .300-221 (.300 whisper) that does not have this issue thanks to an adjustable gas block. Running overgassed, or with possibly out of spec components (ejector hole drilled incorrectly, misshapen extractor possibly) can cause strange ejection. Just because it's a Colt doesn't mean it's in spec. In any mass produced product a certain numbet will be defective, especially with demand so high. Its possible you got a "4:55pm on a Friday" bolt or something.

Definitely try another bolt or BCG to see if the issue persists.

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[Ab_Normal]

Has the gun malfunctioned in any way? If not then it is functioning properly so that is not a worry.

Where does the brass end up after it is fired?

 

[smores]

That's how I see it, unless the brass is hitting the shooter's hand or face I don't see a problem. My arsenal AK mangles brass on the way out, the charging handle dents the crap out of it. People that whine when their AR doesn't eject brass into a 1 ft sq. between 3-4 o'clock make me sad.

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[JAY1234]

I have a 6920 and fired 300 rounds through it. I had some "brass" skid marks on the deflector itself but none anywhere else. My brass was ejected to the right not down. I agree with everyone else who suspects some other outside source caused the marks in question.

 

[byf43]

Are there any unusual markings at/inside the ejection port??

Things to look at:

1. Ejector
2. Ejector spring
3. Extractor tension
4. Is gas system getting sufficient/too much pressure??

What does the rifle do, with different ammo?? Have you tried 'match' ammo???

 

[bkuether]

Its not common and it CAN be corrected. I shoot left hand just as often as I do right hand when testing AR's I service, and my personal AR's. Left Hand AR's are not necessary.

OK friendly discussion here....

But.... They are cool and do puzzle people at the range..... One of these things is not like the other...... I like my Stag lefty. Its nice having something built for me. You can't really appreciate the "other side" of this argument until you have no alternatives.

I would argue that shooting left handed and being left handed are two different experiences. I can't shoot worth a crap right handed. So I can never really know..... I can train myself and get to the point where it "feels OK".

I bet if every AR was left handed there would be desperate pleas to manufacturers to make something "for the rest of us (right handers)".

So with that said, I did order a Core 15 .... I will see for myself here shortly...

I would be curious to know where shell casings go when then hit the back of the deflector. Do they keep moving 90 degrees out from the bolt or do they have SOME rearward tendency?

 

[smores]

I would be curious to know where shell casings go when then hit the back of the deflector. Do they keep moving 90 degrees out from the bolt or do they have SOME rearward tendency?

I have been shooting at the NRA lately and haven't been paying attention. I'm fairly sure they're still going out to the side, I have had a few people take pictures of me shooting at an outdoor range with ejecting brass flying towards then and they were at 3 o'clock. Wish I had a high speed cam lol.

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[nyu04]

To back up what chad said, check this out:

View attachment 75771

The brass is hitting the back edge of the ejection port (at the base of the deflector, you can see the anodizing wearing) before the brass hits the outermost edge. ..

View attachment 75772

Before wrapping around the rear of the deflector. I run this 11.5" upper with an H2 buffer, but also run it suppressed without changing any components, to test reliability in "field" conditions. I have a dedicated suppressed .300-221 (.300 whisper) that does not have this issue thanks to an adjustable gas block. Running overgassed, or with possibly out of spec components (ejector hole drilled incorrectly, misshapen extractor possibly) can cause strange ejection. Just because it's a Colt doesn't mean it's in spec. In any mass produced product a certain numbet will be defective, especially with demand so high. Its possible you got a "4:55pm on a Friday" bolt or something.

Definitely try another bolt or BCG to see if the issue persists.

Sent from my SCH-I535 using Xparent BlueTapatalk 2

Thanks for the pics. I will try another BCG/bolt when I can.

Has the gun malfunctioned in any way? If not then it is functioning properly so that is not a worry.

Where does the brass end up after it is fired?

No, it has been fine but again, only had about 100 rounds through it. Not really worried about the cosmetics, just wanted assurance it's working as intended.

Are there any unusual markings at/inside the ejection port??

Things to look at:

1. Ejector
2. Ejector spring
3. Extractor tension
4. Is gas system getting sufficient/too much pressure??

What does the rifle do, with different ammo?? Have you tried 'match' ammo???

No, have not tried true match ammo. Everything looks fine on the components but again, I'm not a gunsmith. Like I said, not worried about the cosmetics as long as it shoots well. Will keep you guys posted.

 

[trickg]

When I went to Army Basic Training from August to October of 1989, I was issued a Colt M-16A1 rifle, serial number 4786107. I recently looked that number up and came up with a manufacture date of 1971. God only knows how many rounds that thing sent down range in its 18 years of existence before I put my hands on it. For all I know it might have even been IN Vietnam and served time as an actual battle rifle - it was old enough for that. It is by far the loosest M-16/AR-15 I have ever seen in my life, but then I don't suppose it was any more or less loose than any of the others coming off of that supply rack on Fort Dix.

I say all of that to illustrate the point that I doubt if those little marks will ever be anything worth worrying about aside from being a cosmetic "flaw" that might (or might not) adversely affect the value, which is assuming you ever intend to sell it, and assuming we retain the rights to legally sell things like that.

 

[Boom Boom]

If brass is hitting back there on the lower receiver, it must be hitting your firing hand or forearm. Do you feel the brass hitting you?

 

[Bolts Rock]

Rubbing something in the safe is my bet.

 

[sykesville]

Looks to me something was used to pry/assist getting the rear pin out during disassembly of the upper and lower. And that something made those marks.