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AR-15 10.5" upper?

Discussion in 'Gadgets & Gear' started by fishface5, May 26, 2019.

  1. fishface5


    Feb 3, 2001
    been thinking of getting one of these and making a pistol. There are a lot of options out there in a wide range of prices. My main concerns are reliability and reducing muzzle flash. The second probably requires handloading with a low-flash powder and a good flash hider (looking at the FOSSA-556). As to the first it seems like an adjustable gas block is key. But how much difference is there between a $250 PSA upper and a $900 Daniel Defense? Or does it make more sense to assemble one from components?
  2. DocJD


    Jan 29, 2016
    ;) "Makes more sense" ...IMHO ...to build anything AR with a shoulder stock ? Or can you do that legally on this ^^^? :confused:
  3. fishface5


    Feb 3, 2001
    You can add a pistol brace to an AR receiver and it's still a pistol. But if you add a shoulder stock it becomes an SBR and requires a tax stamp
    Bad Ninja, benchwarmer380 and DocJD like this.
  4. heresthedeal


    Oct 3, 2010
    I think it has to be a pistol lower to have a less than 16 inch barreled upper, pistol brace is an add on for a pistol to get around the sbr stamp, imo.
    May want to check before you put one together.
    Cyclops_hammer likes this.
  5. fishface5


    Feb 3, 2001
    yes yes I'm clear on that part. Looking for input on uppers thanks.
  6. Sid Post

    Sid Post

    Oct 14, 1998
    You're going to want a "flash can", not a flash hider on a barrel that short. Muzzle blast is pretty severe too.

    Daniel Defense tends to be a bit over-gassed for higher reliability so, that might not be your best option. I'd look for an 11.5" or 12.5" upper if this is your first use of a less than 16" AR-15 upper.
    Bad Ninja and BBW like this.
  7. ErocSD

    ErocSD Gold Member Gold Member

    Jan 21, 2019
    Go 300 blackout with s flaming pig flash can... perfect setup at 10"
    BBW likes this.
  8. PMCsoldier

    PMCsoldier Gold Member Gold Member

    May 28, 2019
    You can use any lower that has not been part of a rifle. Non designated lowers are any stripped lower that when purchased have not been marked rifle or pistol on ATF form 4473. If you are getting the lower on trade for example simply call the ATF and make sure it was not originally designated a rifle or go to your local gun shop and have them file a undesignated form.

    As per your question no you do not need an adjustable gas block. Adjustable gas blocks are primarily used for over gassing in comp guns such as 3 gun comps etc. 5.56 / .223 over gassing can be controlled much cheaper with the right buffer and buffer spring. Don’t waste your money. The gas port on any standard low pro gas block is way over sized compared to the port on the barrel. If you find you are having cycling problems the problem isn’t your block it’s the gas port in the barrel usually being undersized.

    In 11 inch and lower there is absolutely ZERO difference in any of the manufacturers. There are only a small handful of barrel makers to begin with. I have several Daniel Defense, KAC and many others I will put any 225.00 Radical Defense upper up against my high end stuff and there is quite literally zero difference. ( I’m pistol configurations)

    Do not spend the extra cash on a “pistol” buffer tube as the ATF has officially stated on their letterhead that the type of buffer doesn’t matter at all as long as you don’t have a stock with the pistol as that constitutes an SBR.
    Also do not get all tacticool and put any type of Tango Down or other vertical grip on the fore end of the pistol that also constitutes an SBR. Use an SBA3 brace they are outstanding IMO.

    I have multiple pistols in 9mm, .223, 300 AAC, 458 SOCOM and a few others. The biggest problem is under gassing and a quick tap of the drill press fixes that in five minutes. Good luck
    BBW, Bad Ninja, DocJD and 1 other person like this.
  9. fishface5


    Feb 3, 2001
    PMCsoldier, you da man! Thanks for all the info!
    PMCsoldier likes this.
  10. Mitchell Knives

    Mitchell Knives Knifemaker Moderator

    May 21, 2000
    I built a 10.5" pistol a while back using an upper from PSA.

    Zero issues and seems just as good as my Daniel Defense.

    I didn't notice any issues with flash using the standard A2 flash hider during the day.
  11. jaseman


    Jul 28, 2016
    I built a 7.5" pistol. Complete upper kit from Delta Team Tactical's website, on top of an Aero precision lower. I agree that the upper receiver really isn't a big deal (as long as it's not total junk). Spend the money you save on a nice BCG and trigger.

    I've also got a Krinkov-style "flash can" instead of a standard A2 or a muzzle break. Even at such a short length, I get less flash than from a standard carbine length set-up. Though a have a friend with a 10" that throws freaking fireballs out the front - looks impressive, but it's loud and no one wants to be in the lane beside him! :eek:
    Bad Ninja and DocJD like this.
  12. fishface5


    Feb 3, 2001
    I am awaiting my parts and will update once built. Ended up spending 900 including 5 pmags
    Bad Ninja and BBW like this.
  13. Bad Ninja

    Bad Ninja

    Dec 19, 2018
    Get good ear protection/can or both.
    10.5 556 pistols are ungodly loud.
    300 BO is a bit better with subs, but still very loud.

    As posted above, the PSA uppers are gtg, and the extra money is better spent on a quality BCG and trigger.
    With almost any AR build, the key components are BCG, trigger, and barrel. With SBRs and Pistols, the barrel isn't as much of a factor.
  14. mikal1911


    Jul 7, 2019
    11.5” :thumbsup:
  15. Sid Post

    Sid Post

    Oct 14, 1998
    Dwell time on an 11.5" or 12.5" is enough longer over a 10.5" to improve reliability, reduce parts breakage, and soften recoil in most cases in 5.56 variants. Unless you shoot a lot, parts breakage and reliability are probably not a significant issue. Recoil impulse will be gentler in a longer barrel (assuming normal everyday components) but, most recreational shooters will never notice the difference or care.

    300BO with pistol gas is a different issue altogether. Premium 5.56 uppers with proper gas ports, springs, etc. for your chosen load can be tuned for reduced recoil impulse but, that's a bit extreme for most recreational users.
  16. 1AbominAble1


    Jul 26, 2010
    I have a 7.5 inch 556 upper on a PWS Diablo, it’s tons of fun. The PWS Triad flash suppressor/muzzle break almost completely eliminates flash, look it up, I think you’ll like it a lot.
    Ive never had a “pistol” upper that wasn’t a PWS piston gun so I can’t speak to reliability of the gas guns but my 7.5-5.56 and my 10.75-7.62x39 are Supremely reliable.

    From my research, with H2 buffers and good springs most 10.5-11 inch 5.56 guns run very well.
    There nothing wrong with the PSA guns, I just built one with a friend but if you are interested in building yourself you’ll probably end up with something much nicer for not a whole lot more money.

    Check out the PWS pistol buffer tube, they’re really nice. A guy was selling one here a few weeks ago for a good price, I’m pretty sure that it’s still on the exchange.

    I really enjoy my pistol build but after putting the mount on it for the Can, it rattles the inside of my head if I don’t have the can on it and when fired at night is absolutely stunning to behold.

    Have fun with your build
  17. fishface5


    Feb 3, 2001
    Well one thing I have now learned is not to build an upper from scratch with no prior experience or the proper tools. Gas block is giving me fits. Off to the gunsmith it goes, probably negating any savings. Sigh
  18. Mitchell Knives

    Mitchell Knives Knifemaker Moderator

    May 21, 2000
    What kind of problem were you having?
  19. fishface5


    Feb 3, 2001
    I dimpled the barrel for the gas block screws in the wrong place, because it had moved after firing, then figured out where the dimples should actually be, and now the barrel looks like an artillery range but it still doesn't work smoothly.

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