ar upper help!

Discussion in 'AR15/10 Rifles' started by beakus33, Mar 7, 2012.

  1. beakus33

    beakus33 Well-Known Member

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    I have a Surplus Ammo&Arms lower that need tweeking,i'v had 3 uppers on it and only one fit really nice,the bushmaster. the YHM and DMPS both fit good on the pivot pin but the rear is REALLY tight.any ideas? my thought was the holes are supposed to be for a .156 pin plus a few thousands for clearance so i'm wondering about a reamer to remove just the hard coat in the rear hole,.001-.002 i have precision pins and a good selection of reamers so i can get to within .0005-.001 of what it is now with the coating in the hole then just remove the .001-.002 of coating.
     
  2. ilscungilli

    ilscungilli Well-Known Member

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    I've read in a few places that it will loosen up after you shoot them a few hundred rounds. Have you shot this rifle much with the tight upper/lower configuration?
     

  3. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    This is true, however I would return everything you bought and start over with mil spec componets. Who made that lower again?

    When you say "fit real nice" what does that mean? Please be more decriptive.
     
  4. beakus33

    beakus33 Well-Known Member

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    the rear pins are so tight that once there pushed in you have to flip the weapon over and drive the pin out. the bushmaster upper fit good,not loose, but you could push the pins out with a finger. the YHM & DPMS there would be no field dissasymbly.
     
  5. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    Ok that sounds fine they will losen as you shoot it.
     
  6. The7mmSTW

    The7mmSTW Well-Known Member

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    i had a similar issue, after 300+ rds it loosed up real nice
     
  7. beakus33

    beakus33 Well-Known Member

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    thanks guys, i did run a reamer in them today,took off.001, from a .251 hole to .252, the rear hole is an oval hole not round so it only hit in the center,just knocking off the hard coat but made a ton of differance,now they slide in smooth with out forcing them but yet still a little stubbern to get out. now all i need is my 6.5 grindel barrel and i'll have another upper ready to go!
     
  8. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    Im looking for that barrel to have not found wone I like yet
     
  9. beakus33

    beakus33 Well-Known Member

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    Are you looking for something paticular in the 6.5 barrel?
     
  10. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    Yep 18" barrel, the AA does not look bad. I got a price from Saturn to cut a barrel to my specs (SPR) but I dont have 550 to drop on that right now. Braownells had one I was going to buy but they have been out of stock for a few months.
     
  11. beakus33

    beakus33 Well-Known Member

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    yep, thats a little steep, apperantly on "sons of guns" all you need is a $50 chop saw to wack of a few inches of a $2000 barrel.i was looking at the AA 20'', the only thing i dont likeon the longer barrels is that the gas block is in front of the free float tube,i'd like it to be under the tube. what i did on my carbine is to put a rifle length tube on a 16" barrel.
     
  12. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    I have a 20" 5.56 upper and the gas block is covered with the Larue 13.2" rail
     
  13. brentc

    brentc Well-Known Member

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    Here is one I found that may work well. It's the LBC and it doesn't have the screwy threads that AA uses. Stainless 18" SPR with 5r rifling for a reasonable price doesn't sound all that bad.

    264LBC
     
  14. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    Thats not a bad price at all