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Gunsmithing AR Ejection location as an Indicator?

Halfnutz

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  • Jan 14, 2008
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    Peoria County, Illinois
    So I've seen the graph showing that 3-4:30 is the ideal ejection location. My concern is not the ejection location but what is best for the rifle in so far as the timing of unlocking of the bolt.

    What guidence is there for tuning this? ejector/ejector spring/extractor vs buffer wieght/spring and carrier wieght?
    I left out anything to do with gas port size and or adjustable gas systems so as not to muddy the waters any more than needed.

    LMT 18in 5.56 throws them in the 1-2 o'clock position even after switching from a standard buffer to an H1 buffer ( Geissele Super 42) and semiauto bolt carrier. Note: Recoil impulse seems softer allowing for better spotting of shots after changing too the Super 42.
    XM193, M855, Superformance 73gr ELD, IMI 77gr, Norma 223 Match 77gr and various handloads 55-77gr all land pretty close to the same 1-2 o'clock area.

    Noveske 10.5 in 5.56 ejects @ 3 o'clock with an H2 buffer/FA carrier and XM193.

    What is the down side of too heavy a buffer and/or carrier if there is not an obvious reliability issue?
     
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    Take that pie chart, and trash it. It's dumb and useless.

    Does the gun fire, and lock back ejecting ammo in a consistent pile? If yes then you're good.

    Heavier buffer or carrier just delays ejection. It requires more gas to unlock and move the carrier back. It also slows down the momentum of the carrier.

    I have rifles that eject at 2, 3, 4, and 5. One is because of the deflector and strength of the dual ejector causing it to go to 2. Another is the lack of a deflector going to 5. The pie chart is truly useless nonsense.
     
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    I closed mine and opened it one tick (superlative block) at a time shooting one round in the mag at a time until it locked back on the empty mag. It timed up with 3-4 o’clock.
     
    As I mentioned the ejection location is not a concern. I would like to know if there is a downside to running a heavier carrier/buffer/spring combination, outside of being too heavy that it effects reliability.

    The LMT and Noveske are both "higher end" AR's., albiet configured for different use, i.e a precision rifle vs a pistol configuration respectivly.

    The 18" LMT barrel is fairly new and I am still working on finding what ammo/hand load to settle on. I intend to use it on prarie dogs if I can get it to perform as I want. Spotting hits at a higher magnification and getting back on target quickly are my criteria. The difference in the ejection pattern was just something I noticed an made me wonder.