Ar-15 class III build

Discussion in 'AR-15 Discussion' started by jakeball, Apr 16, 2014.

  1. jakeball

    jakeball New Member

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    Looking to build a rifle with a short barrel 8-10 inches. And a thread on suppressor, with a handgaurd/rails that come 2-4 inches shy of the end of the suppressor. Im no ar expert and im new to the platform. So ill need help on what i should get. This picture is the closest i could find on what i want.

    Also anyone familiar with the sig mpx carbine is what im trying to recreate on a .223.

    Thanks for the help! ImageUploadedByFirearms Talk1397689998.826357.jpg


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  2. JonM

    JonM Moderator

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    Before you do anything you need your sbr stamp and a properly marked lower reciever.

    Once you get that done THEN you can build out your rifle.

    I would suggest build it out as a pistol while your waiting on the stamp.

    At 8-10" a 223/556 is going to have about the same power level as a 22wmr... pretty wimpy. I would go 300blk or use a pistol caliber upper.

    Rra is what I would source the lower from and everything else bravo company usa.
     
    Last edited: Apr 16, 2014

  3. seancslaughter

    seancslaughter New Member

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    I agree with jon on the choice of round being wimpy you should definitly think about 300 blk that round was designed for short barrel/suppressor use. Either that or use a pistol caliber like 9mm
     
  4. jakeball

    jakeball New Member

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    Could you give me velocity on 556/223 on a 10 inch barrel? Trying to find charts online but nada. Im not looking to go past 100 yards with rifle. Uses for this rifle are gonna be cqb drills. And plinking at distances of 50 yards in.

    As you remember from my other post the mpx carbine prob wont be sold legally. If they will it wont be for some time. So i wanna have something on the back burner in the mean time, just in case.


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  5. JonM

    JonM Moderator

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    Muzzle velocity is around 2300-2400fps right at the muzzle and drops rapidly as the barrel length decreases down to about 1800fps at 5".

    What this means is the 223/556 loses pretty much all of its ability to stop threats reliably and probably will have issues stabilizing in such short barrels at such low velocity.

    Its the same issues faced by the fn5.7

    This is using milspec ammo. Most off the shelf ammo won't be loaded to that standard so performance may be worse.

    223 bullets bleed energy very fast terrible ballistics and they make up for that with speed. So by the time the bullet drops to useless 2300ish fps velocity its several hundred yards down range. When it comes out of a short barrel your waaaay behind the curve before its gone an inch down range and bleeding energy and velocity skippy quick.

    For what your looking to do 9mm or 40sw upper would be ideal. I would lean 9mm as its got better dowrange velocity than a 40 less recoil and mags are easier to get if you go with a rra upper.

    9mm can be loaded hot for a sbr especially out of a 10" barrel its a nasty little bugger.
     
    Last edited: Apr 16, 2014
  6. clr8ter

    clr8ter New Member

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    Interesting thread. Doesn't the OP need TWO stamps? One for the SBR, and one for the suppressor?
     
  7. jakeball

    jakeball New Member

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    Yupp.


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  8. jakeball

    jakeball New Member

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    Any mags out there that look like an AR mag but hold 9mm? I cant get past the goofy looking stick mags on the market for 9mm ars.


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  9. Point6liter

    Point6liter New Member

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    I felt the same way seeing the 9mm stick mags in pics online. 9mm Uzi mags don't look bad at all in person in an ar. I have been doing some r&d on a 5.5" 9mm suppressed AR pistol for a local manufacturer. If you have a chance to see one in person, I think you won't feel the same way. Next time I am working on it I will get some pics.
     
  10. jakeball

    jakeball New Member

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    Thanks would be much appreciated!!


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  11. JonM

    JonM Moderator

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    On a rifle 16"+ they are a bit weird looking but on a sbr... they look good.
     
  12. seancslaughter

    seancslaughter New Member

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    I personally think the 9mm sticks look pretty cool. Reminds me of a pic of my dad in Vietnam with a 9mm car


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  13. jakeball

    jakeball New Member

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    Maybe on a dedicated ar lower. Not crazy bout 9mm mag hanging out of a 223 mag well, like it dont belong.


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  14. beastmode986

    beastmode986 New Member

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    Why not just go .300 blackout ?


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  15. jakeball

    jakeball New Member

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    It $1+ a round ill go broke thats why. Lol
    And no reloading for me its not possible for me, at least anytime soon.


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  16. sweeper22

    sweeper22 New Member

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    Whether 5.56 or 300blk, it's best not to get any shorter than 10.5" in my experience.

    The shorter the barrel, the more noise you're attempting to suppress. A suppressed 5.56 under 10" doesn't tend to yield the results many hope for (and that can be an expensive and time consuming regret). Stay in the 10.5-14.5" range for a suppressed 5.56. For a 300blk, under 10" is a little more practical. But my 300blk SBR is 12"...so perhaps that implies something about my own preferences.
     
  17. t_humm

    t_humm New Member

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    Similar question: If it was an SBR, but has a suppressor pinned on and it now reaches rifle length do you need two stamps?


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  18. clr8ter

    clr8ter New Member

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    I have never heard of a pinned-on suppressor. I don't know for sure, but I'm going to guess; Yes.
     
  19. jakeball

    jakeball New Member

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    Likely be a longer wait period if you want to avoid the stamp, as it would be non traditional, and needs investigation by the atf.


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  20. sweeper22

    sweeper22 New Member

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    No, because the government does not want more of your money...please consider that a completely sarcastic, smart-aleck answer. No disrespect intended.

    Of course the government wants to relieve you of any expendable funds! So consider it a safe bet that you need two tax stamps. Besides, the ability to remove your suppressor, properly clean it, and even go shorter/unsuppressed is probably worth the $250 and 10-month inconvenience of an additional Class-3 application.

    I'd say you'll be best served buying both stamps to CYA.