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.

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.