Dented Spent Brass from AR45

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  • calicojack

    American Sporting Rifle
    MDS Supporter
    May 29, 2018
    5,348
    Cuba on the Chesapeake
    So I shot my New Frontier Armory AR45 today (Glock mags). The accuracy seems to be good, certainly what I would expect from an 8" barrel braced pistol. But the ammo feed and ejection, while mostly reliable, had a few FTFs. However, what I found most troubling was these very consistent dents in the brass. Suggestions? I am using a 10 ounce buffer and a stiff buffer spring designed for a PCC AR. The primers also look a bit flat to me.
     

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    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,818
    Might need to slow that bolt down some more. If you can get someone next to you with a cell phone with super slow-mo, that might help diagnose where the damage is occurring. If the case is spinning inside the ejection port...
     

    DavidA

    The Master of Disaster
    Dec 6, 2013
    371
    Annapolis
    Just thinking about the problem I would think the brass rotates pretty quickly once it clears the loading port. Probably hitting the crack side gusset of the ejection port. You could try slowing down the bolt. Not sure of your setup but a heavier spring or a adjustable gas block may mitigate the problem.


    Sent from my iPad using Tapatalk
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,818
    Just thinking about the problem I would think the brass rotates pretty quickly once it clears the loading port. Probably hitting the crack side gusset of the ejection port. You could try slowing down the bolt. Not sure of your setup but a heavier spring or a adjustable gas block may mitigate the problem.


    Sent from my iPad using Tapatalk

    It's a blow-back system. No gas, but I agree. I think the cases are spinning inside-out of the ejection port.

    That said, those cases are re-formable. But they do show there's too much energy in there.
     

    calicojack

    American Sporting Rifle
    MDS Supporter
    May 29, 2018
    5,348
    Cuba on the Chesapeake
    It's a blow-back system. No gas, but I agree. I think the cases are spinning inside-out of the ejection port.

    That said, those cases are re-formable. But they do show there's too much energy in there.

    I am going to try the slo-mo video and see what that shows.

    If it's spinning inside the receiver, is the ejector the issue then? I am already running a 10 ounce buffer and heavier than normal spring.
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,818
    I am going to try the slo-mo video and see what that shows.

    If it's spinning inside the receiver, is the ejector the issue then? I am already running a 10 ounce buffer and heavier than normal spring.

    I would wait and see what the video shows.

    I would also try other ammo. Are those steel cases?

    Refresh my memory; this is not a CMMG RDB system? If not, maybe look into a Scheels DBS(I have one sitting under my Christmas tree at this very moment). Assuming they will work on a .45 ACP gun.

    https://coreys28.sg-host.com/roller-delayed-buffer-system-info/
     

    calicojack

    American Sporting Rifle
    MDS Supporter
    May 29, 2018
    5,348
    Cuba on the Chesapeake
    I would wait and see what the video shows.

    I would also try other ammo. Are those steel cases?

    Refresh my memory; this is not a CMMG RDB system? If not, maybe look into a Scheels DBS(I have one sitting under my Christmas tree at this very moment). Assuming they will work on a .45 ACP gun.

    https://coreys28.sg-host.com/roller-delayed-buffer-system-info/

    Yes it is steel case.
    No, not the RDB system, it's using the New Frontier Armory barrel and Kaw Valley Precision BCG. Also Kaw Valley 10 ounce buffer and Kaw Valley "308/Pistol Caliber Extra Power Carbine Buffer Spring".
     

    GunBum

    Active Member
    Feb 21, 2018
    751
    SW Missouri
    Dented brass is just an annoyance. That brass (steel, whatever :lol2: ) is not dented enough to preclude reloading. Is it ugly? Yes. Can you spend a bunch of effort making it go away? Yes. Is it worth fixing? For me, no.
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,818
    Yes it is steel case.
    No, not the RDB system, it's using the New Frontier Armory barrel and Kaw Valley Precision BCG. Also Kaw Valley 10 ounce buffer and Kaw Valley "308/Pistol Caliber Extra Power Carbine Buffer Spring".

    Steel cased ammo can have a different effect on semi-auto guns, especially PCCs. Like gunbum said, that denting in brass is still reloadable. The thing that gives me pause, those cases are not only dinged, they looks abraded as well. That was what made me think the cases were still 'banging' around inside the ejection port as the bolt picks up the next round and chambers it. If that is the case, the problem could either get better or worse as the gun wears in. You can try replacing the extractor spring to see if it improves. That would be a fairly cheap fix if that is all it is.

    I still thing you need to try better(brass cased) ammo and see how the gun behaves with that.
     

    calicojack

    American Sporting Rifle
    MDS Supporter
    May 29, 2018
    5,348
    Cuba on the Chesapeake
    Steel cased ammo can have a different effect on semi-auto guns, especially PCCs. Like gunbum said, that denting in brass is still reloadable. The thing that gives me pause, those cases are not only dinged, they looks abraded as well. That was what made me think the cases were still 'banging' around inside the ejection port as the bolt picks up the next round and chambers it. If that is the case, the problem could either get better or worse as the gun wears in. You can try replacing the extractor spring to see if it improves. That would be a fairly cheap fix if that is all it is.

    I still thing you need to try better(brass cased) ammo and see how the gun behaves with that.

    Thanks. :thumbsup:
     

    calicojack

    American Sporting Rifle
    MDS Supporter
    May 29, 2018
    5,348
    Cuba on the Chesapeake
    So I have 10 dummy rounds; brass with 3 D printed plastic bullets. I had someone do a slo-mo Apple Iphone movie while I cycled the rounds through. You can see the rounds do a 180 inside the upper before getting ejected out.
    Not the same as a live round but might be indicative.

    (removed)
     
    Last edited:

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,818
    Is your ejector replaceable? It might be worthwhile trying a shorter one if it is.

    It should be John. They are in their 9mm lowers.

    It's not hard to imagine what is causing the damage. It is the trailing edge of the ejection port. I would still need to see that operation done with an empty/fired case in slo-mo during a firing sequence. There seems to be a problem somewhere along the extraction sequence. Slow the action down? Take a little off the ejector? Find a way to add a brass deflector? :shrug:
     

    John from MD

    American Patriot
    MDS Supporter
    May 12, 2005
    22,734
    Socialist State of Maryland
    It should be John. They are in their 9mm lowers.

    It's not hard to imagine what is causing the damage. It is the trailing edge of the ejection port. I would still need to see that operation done with an empty/fired case in slo-mo during a firing sequence. There seems to be a problem somewhere along the extraction sequence. Slow the action down? Take a little off the ejector? Find a way to add a brass deflector? :shrug:

    If he shortens the ejector, the case will stay on the extractor longer and will eject at the rear of the port. If it is timed correctly, it will eject into the rear of the port which should sent it outward. Well, that's what I would try anyway. :D
     

    teratos

    My hair is amazing
    MDS Supporter
    Patriot Picket
    Jan 22, 2009
    59,775
    Bel Air
    The Scheel roller delayed system works fine with .45, or so they report. Not sure why it wouldn't. It can tame the beast.
     

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