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Short Stroke

Discussion in 'NFA & Class III Discussion' started by BIGJAKE, Oct 6, 2009.

  1. BIGJAKE

    BIGJAKE Sharpshooter

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    I have an issue with my AR going through anywhere from 15 to 25 rounds in a mag before it drops the hammer on a round without setting it off. Sometimes it will empty a whole mag and other times it will have this FTF. The gas key is staked and not moving and all of the gas rings are new. I do not think that this issue is a gas system problem because it functions just fine on semi with no FTF problems. I have heard that this can be casued by a recoil buffer spring that is too strong. Any help would be appreciated.
     
  2. CAR-AR-M16

    CAR-AR-M16 Sharpshooter

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    I assume you are talking about a full-auto AR that fires fine in semi, but ocassionaly will not fire a round in full-auto. The symptoms are that the round chambered and the hammer fell, but the round did not fire. If so, these are the classic symptoms of "bolt bounce". In full-auto the sear releases the hammer at almost the same instant that the bolt carrier is bouncing back after slamming a round into the chamber. The energy of the hammer is expended closing the bolt carrier and does not have enough force left to ignite the primer. This is usually seen when using a carbine buffer tube with too light a buffer. If you are using a standard buffer, try an H buffer, If you have an H buffer, try an H2 buffer. Some folks run a 9mm buffer, but I find the H2 works best for me.

    If you are using a RDIAS, it could be a timing issue as well. Try this link for info on how to time an RDIAS: http://www.quarterbore.com/nfa/dias.html

    YMMV. Hope that helps.
     
  3. BIGJAKE

    BIGJAKE Sharpshooter

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    That is exactly what I was refering to. Yes, I am using a carbine buffer so I will change that out to a H buffer and see how she runs. This makes total since now because I had A2 stock and buffer on before with no FTF isues to speak of (minus ammo problems) and one I put a carbine stock I have been having this issue. Thank you very much for your help and I will let you know if this corrects the problem.
     
  4. Glock Nut

    Glock Nut Sharpshooter

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    have you got this problem fixed?

    GN
     

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