Times Have Changed: Why You Might Actually Want to Try a 7.5″ 5.56 AR-15 Build

I have been shooting AR-15s for years now and apart from the mild cool factor, I have never really considered owning an AR-15 chambered in 5.56x45mm with a 7.5″ barrel. In fact, you could say that I thought they were a bit silly. Times changes and so do opinions.

7.5 Upper

It is true that just about any other common AR-15 chambering is a better performer than 5.56/.223 in such short barrels. That includes 6.8SPC, 300BLK, and even the 9mm Luger (in some ways like noise and flash but not necessarily in terminal ballistics). If you want to build a super-short AR-15 and your budget allows, go ahead and take on a new caliber. If your budget doesn’t allow or you just don’t want to take on a new caliber, there are a five reasons that super short 5.56 chambered guns may finally be viable.

Here is how I talked myself into building one…

  1. Ammo – The proliferation of advanced projectiles like the Barnes TSX and some bonded bullets means that there is finally off-the-shelf ammunition that will expand at the more modest velocities produced by 7.5″ AR-15 barrels. There are new choices coming out all the time and projectile design continues to advance at an amazing rate.
  2. Muzzle devices – Previously, having a super short 5.56 chambered AR-15 meant throwing massive fireballs every time you pulled the trigger. That is no longer the case. Advanced flash suppressors like the AAC Blackout, White Sound Defense FOSSA 556, B.E. Meyers 249F, and others can all but eliminate the flash on these shorter barrels. This is especially true if the shooter chooses their ammo carefully. If you don’t care about flash, there are a now number of linear comps on the market that will direct some of the blast away from the shooter and some even suppress flash a bit like the Black River Tactical Covert Comp. You can even couple a blast shield with an effective flash suppressor like the Griffon Armament taper mount series or a YHM Phantom with a Simplistic Shooting Solutions Blast Shield to suppress flash AND direct concussion away from the shooter.
  3. Reliable barrels – There was a time when there weren’t very many 7.5″ barrel options that worked well without being grotesquely over-gassed. Noveske was pretty much the only quality option. Now, you can get high quality 7.5″ barrels from Ballistic Advantage and Aero Precision just to name two. Both use gas port specs that are on the small side and their barrels run well. You can also go with a piston set up from PWS or Adams Arms, both of which have solid reputations for reliable function. If you don’t want to build your own, Andro Corp Industries offers prebuilt 7.5″ uppers that use Ballistic Advantage barrels. I purchased mine from them and I have been very pleased so far.
  4. Law Tactical AR-15 Folding Stock Adapter – The moment that I finally laid hands on a Law Tactical AR-15 Folding Stock Adapter was the moment that I hoped I could make a 7.5″ AR-15 work. An AR-15 pistol equipped with a 7.5″ barrel and folding stock adapter will measure at right around 18″ long when folded. That means it can be carried in a normal backpack, tool box, messenger bag and all sorts of other places that even a 10.5″ barrel won’t fit without breaking it into its separate components. The Law Tactical Folding Stock Adapter helps turn these builds from interesting range toys to something like a concealable PDW with potentially interesting application for the private citizen.
  5. Advent of the AR Pistol – Finally, the advent of the AR-15 pistol has made it easier, less costly, and less risky than ever to try a 5.56 chambered AR-15 with a short barrel. You can test and tweak various ammo/muzzle device combinations before you plunk down your cash for a tax stamp… or just keep it as a pistol.

To recap, 5.56×45 is still less than ideal from a short barrel but thanks to several advancements, it may be more viable than ever.

JTT AR Pistol 3


18 Responses to Times Have Changed: Why You Might Actually Want to Try a 7.5″ 5.56 AR-15 Build

  1. Bubba June 12, 2015 at 17:24 #

    You’re right about “finally”.
    Good luck on finding a Law Tactical Folding Stock Adapter. They have some kind of exclusive deal with an AR manufacturer/assembler which causes them to always be “out of stock” on that site for a year. They use a mailing list to send you one when they feel like it. I don’t know if they are that successful or that lazy.

    They only manufacture and sell 2 things, yet can’t keep the stock adapter “in stock”. (hahaha)

  2. mike waters June 12, 2015 at 22:36 #

    Is that set-up consider a “SPR” ?????

    • Matt June 12, 2015 at 22:41 #

      I am going to assume you mean SBR and no. The one shown is an AR pistol.

      • Metal Matt June 14, 2015 at 11:43 #

        “SPR” Is an abbreviation for “Special Purpose Rifle.”

    • Metal Matt June 14, 2015 at 11:41 #

      SPR variants are usually based off the MK12 Mod X; traditionally SPR variants are used to reach out a “touch” someone at Rutherford distances than a traditional M4 or the like.

      • Metal Matt June 14, 2015 at 11:43 #

        at further distances*

  3. Mic June 12, 2015 at 22:37 #

    Is there a com0any that makes a suppressor that can handle a 7.5 barrel? I wouldn’t expect much noise suppression, but hopefully could eliminate flash and concussion.

    • Matt June 12, 2015 at 22:42 #

      Mic, I am not sure if there are any made specifically to handle 7.5″ barrels or not. I know that some manufacturers won’t warranty a can used on anything shorter than a 10.5″ barrel.

  4. Lampwik June 13, 2015 at 02:36 #

    The Silencerco Saker 556 and 762 are factory warrantied for 7 inch barrels.

  5. Matt June 13, 2015 at 09:00 #

    Did you means Barnes TSX?

    • Matt June 13, 2015 at 09:05 #

      Sure did! Good catch.

  6. MKL June 13, 2015 at 16:24 #

    The Thunder Beast 223A is good to go on a 7″ barrel.

  7. Bruce June 14, 2015 at 09:46 #

    I have been told by an AR gunsmith that the 7.5 barrel “fad” started as a way to utilize the waste from barrel blanks. I wonder if there is any truth to that …

  8. Wes June 14, 2015 at 09:59 #

    What type of sight is on that weapon?

  9. Uxi June 17, 2015 at 09:23 #

    Looks like an Aimpoint T1 or possibly T2

    • Matt June 17, 2015 at 09:24 #

      That is a Primary Arms MD-ADS that I have been testing.

  10. Wes June 17, 2015 at 09:36 #

    Very nice, who makes the riser mount?

    • Matt June 17, 2015 at 09:37 #

      That is an ADM mount.

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