9mm Subsonic…. why 180grain 9mm?

I have had the luxury of shooting suppressed firearms since the year 2000. Back then, while suppressors were not uncommon in the circles that I ran in, consistently reliable subsonic ammunition was not so easy to come by. I recall buying numerous brands of 9mm ammo, claiming to be subsonic, and that were subsonic in most handguns, yet none of them remained subsonic in my Keltec Sub2000, or my 9mm machine guns. As a result, I began loading my own 9mm with the heaviest projectile of the day, that being the 147 grain FMJ or Hollow Point. Still, a load that would cycle my suppressed handgun would be supersonic in a 16” barrel carbine or subgun. What I really wanted was one load that functioned and remained subsonic-quiet in all my suppressed 9mm firearms.

Well, it only took me 20 years to pull it off, but I finally spent the time and the money to focus on this project and refined a 9mm subsonic load using a hardcast coated lead bullet that is heavy enough to build sufficient back-pressure to cleanly ignite a slow-burning gunpowder without exceeding SAMMI pressure specs for the 9mm, and cycles any semi or full-auto firearm that you shoot it in, all the while remaining subsonic. It also performs well in shorter-barreled handguns. Designing that much weight into a 9mm projectile that stabilizes in the conventional twist rates found in today’s firearms, and still allowing enough case capacity to propel the bullet at a sufficient velocity took a minute. That being said, the Meplat on this projectile is .230 inches so there is not much taper from the bullet-shank-diameter to the Meplat diameter. As a result, short throated barrels with little or no leade into the barrel rifling will quickly cause excessive leading in the throat area causing failure to feed successive rounds fully into the chamber. Of the numerous carbines, subguns and handguns we tested this ammo in, the CZ P09, exhibited this lead fouling. Talking with my bullet caster who is a CZ fanboy claims all CZ’s are short throated and require using a piloted throat reamer** with a slight taper to create an adequate throat or freebore in his CZ’s, which in addition creates a nice leade into the barrel rifling improving accuracy by optimizing bullet alignment as the projectile enters the rifled portion of the barrel.

Accuracy for this heavy bullet at 100 yards out of a Keltec sub 2000, and an AR platform pistol, is 1 to 2 MOA. See my video demonstration. For those of you unfamiliar or skeptical about Hi-Tek Supercoat, I can attest to the fact that after firing thousands of rounds of coated bullets it virtually eliminates lead fouling, at least with all the subsonic ammunition that we load and shoot. While I developed this ammo specifically for use in suppressed firearms it cycles unsuppressed weapons as well. As I discovered with my own Glock 19 I will need a muzzle booster, or Nielsen device, to get the Glock to cycle with this ammo and a suppressor attached.

Last but not least at 950 to 1000 feet per second this 180 grain bullet produces between 360 and 400 foot pounds of energy at the muzzle with very manageable recoil even in subcompact 9mm handguns. The following is a listing of velocities we obtained in various 9mm firearms:

Keltec Sub2000 16” barrel – 1026 fps

FoxTrot Mike FM9  7” barrel – 945 fps

Glock 19 Gen 5  4” barrel – 850 fps

S&W Shield Plus  4” barrel – 850 fps

**Pacific Tool & Gauge 9mm Throater — PT# 88841 Rev A.

Leave a Reply

Your email address will not be published.