Question about ejected brass

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13 years 8 months ago #7047 by vlaflin
Question about ejected brass was created by vlaflin
My AR 10 recently started leaving a fairly sizable indention on the rim of the spent cartridge. It would appear that the ejector is pulling on the rim excessively hard to the point of rolling the rim up. I have tried everything from military surplus to Federal Gold Medal Match ammo and it seems like it effects them all equally. Has anyone else encountered this problem. Thanks in advance for any help.

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13 years 8 months ago - 13 years 8 months ago #7048 by BUILDING MY SASS
Replied by BUILDING MY SASS on topic Re: Question about ejected brass
I have heard of this...can't remember the cause...I want to say a timing issue but I am not sure....I will do some checking....
Have you done a MAJOR cleaning of the chamber.....
I do know that if you shoot brass cased ammo then switch to steel and visa verse that it can cause similar issues....but as I said...I will do some checking....
BMS
Last edit: 13 years 8 months ago by BUILDING MY SASS.

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13 years 4 months ago #8250 by Bluegrassdan
Replied by Bluegrassdan on topic Re: Question about ejected brass
Just a thought, but one I have dealt with before, check the gas tube opening diameter on the chamber side. If your getting more gas into the system, the buffer is going to suffer and the ejection cycle is going to be rougher. This is sometimes caused by shooting really hot loads or crappy surplus (machine gun ammo)that is going to wear out the ID of your gas tube, causing harder ejection, that will cause a dent in cases.

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13 years 4 months ago #8278 by ARMALITE TR
Replied by ARMALITE TR on topic Re: Question about ejected brass
TECHNICAL NOTE 17: MARRING OF CARTRIDGE CASES

GENERAL:Cartridges fired in AR-10 and M16 family firearms bear characteristic
scratches and marks which shooters sometimes think indicate defects.

FACTS:The following scratches and marks are typical with ArmaLite patent firearms, from a variety of manufacturers, and do not indicate defects:

1. Light scratches along the length of the cartridge body. Caused by contact with magazine feed lips or another cartridge during feeding.

2. Two dents and related scratches on neck. Caused by neck striking 2 locking lugs during extraction. The ejector forces the case to the side, causing the contact.

3. Random circumferential scuffing of body. Caused by case brushing past chamber mouth during feeding.

4. Dent on case body or mouth. Caused by case contacting upper receiver during ejection.

5. Circular mark on edge of base, with shiny brass or shaved brass in evidence. Caused by case being pressed into ejector hole, with some burnishing or cutting as the bolt rotates.

6. Scratches or slight rim deformation caused by the extractor snapping over rim, and the energy applied during extraction.

7. Light protrusion of primer metal around the firing pin strike (cratering). Caused by clearance between the firing pin and firing pin hole; varies depending on primer hardness and cartridge pressure.

Other marks, including heavy machine marks pressed into the brass, or repeated case failures or primer punctures, can indicate a flaw in the rifle or use of reloaded ammunition. Contact ArmaLite® if you experience problems

Hope this helps.

TR

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