Follower or clip mag feed for bench accuracy?

Discussion in 'AR15/10 Rifles' started by barnabus, Jun 19, 2011.

  1. barnabus

    barnabus Member

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    Would there be an accuracy advantage of single feeding an AR10 from the bench vs. allowing the mag to feed the weapon during a long range scored bench match? If so,explain why.Thanks
    Barnabus
     
  2. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    The only reason guys single round load in AR pattern weapons system is due to limitations in COAL because of detachable box magazines. When you see guys single round loading their rifle its beacuse they are shooting heavy long bullets in the 80g plus range thay will not fit in the confines of the mag system. More accurate at longer range? In most cases yes due to higher BC worth it? I have no idea if its worth it I suppose if you want to win it is. But it also depends on what type of comp we are talking about to.
     

  3. Kevin Thomas

    Kevin Thomas Well-Known Member

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    You could just try it and see, just to verify in your own rifle, but I'd go with the single feed. The transition from magazine to feedramp to chamber is not a gentile one. There's another point to consider here as well; OAL. Not the OAL you set when you loaded the rounds, but the OAL they'll reset themselves to when you trip the bolt. You're dealing with a very large and expensive kinetic bullet puller there, especially with the added mass of an AR-10 platform. I've never seen an AR-15 that wouldn't pull the bullets to some degree during chambering. This can go from very slightly (but still measurably) with mil spec ammo using neck sealant and a crimp, to quite dramatically when using minimal neck tension in match loads. Bottom line, and I keep repeating this, Service Rifles (autos in general) are not bolt guns, and they need to be treated very differently.

    You've got a significantly different situation here than you do with M1s and M14s (which should NEVER be fed directly into the chamber), where this sort of action risks a slam-fire. These guns MUST be fed through a magazine, simply to retard the bolt velocity a bit as the gun goes into battery.

    From a bench, I'd probably feed directly into a chamber, and close the bolt gently as possible.
     
  4. B-RAD

    B-RAD Well-Known Member

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    Don't waste your time with an AR-10 but an AR-15 - yes... it will help...
     
  5. barnabus

    barnabus Member

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    do what? How about something to support a statement like this?
     
  6. roop

    roop Member

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    last winter i purchased a bushmaster .308 orc. In my reloading experimental phase i did some testing with crimps and neck tension. Now, i don't have numbers in front of me but i can tell you that no matter how much i crimped the necks, the bullets would move. dependng on bullet weight and profile, it could be in or out. bottom line here, if you want consistent velocities, you need consistent chamber pressure. if you are plinking at distances under say, 300m you probably won't notice a significant amount of vertical stringing, but for competition accuracy my recommendation would be to let the bolt down about halfway, then release it, or use that foward assist to seat the bolt. that way you can be sure of consistent performance.
     
  7. Boss Hoss

    Boss Hoss Well-Known Member

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    In a magazine fed semi if the magazine is used to feed the rifle if you had concentricity in your loaded rounds you no longer will.
     
  8. TnTom

    TnTom Well-Known Member

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    Boss you lost me on that one. Please elaborate. Very interested
     
  9. long450

    long450 Well-Known Member

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    Single loading is more accvurate due to consistancy. David Tubb on one of his DVD's does a demonstration with an SR25 in 308 shoooting 175 gr SMK's and talks about the fact that the riflre is accurate in single load mode but, not as accurate in rapid fire mode. I would say that 300 yards or less distance, it would not matter much. I have shot many thousands of rounds out of an AR platform in both modes and single loading and seating long for heavy bullets will give you the best accuracy by reducing group size by around 50%. If you are shooting 20" target at 600 yards, you should be able to hit it either way.
     
  10. TnTom

    TnTom Well-Known Member

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    Meaning the chambering process in mag feed adds a degree of eccentricity to the round while being delivered to the chamber?

    I do know mag feeding will move a hand loaded round (bullet) forward from its initial seat and possibly impact the coaxiality.

    Is that what you mean?

    Thanks Tom