Good afternoon suppressor fans and welcome back to another Silencer Saturday segment brought to you by Yankee Hill Machine, manufacturers of the Turbo K 5.56mm suppressor. Last week we talked about subsonic 9mm ammunition choices for pistol caliber carbines like the H&K SP5 and I’d like to continue the conversation with some 185gr 9mm from Seismic Ammo. With these massive bullets we are entering subsonic 300BLK territory. How do they sound? Stick around to find out.
SILENCER SATURDAY #128: Suppressed Super Subsonic 9mm From Seismic Ammo
After last week’s journey to find a subsonic round for the H&K SP5, the good people at Seismic Ammo reached out and asked if we’d like to take a look at some of their rounds. 185gr 9mm? I’m so in.
The Seismic rounds are built off the Shellshock Technologies two-piece metal cases (Aluminum & Nickel alloy) that allow for much higher pressures than brass while being 50% lighter.
- Website: https://www.shellshocktechnologies.com/shop/cases-reloading-tools/1500-new-unprimed-9mm-luger-nas3-cases/
- Are 50% lighter than brass cases
- Offer greater lubricity and will not abrade, clog, foul, wear-out or damage breach and ejector mechanisms.
- Offer greater corrosion resistance, tensile strength (2x stronger) and elasticity than brass.
- Will not split, chip, crack or grow (stretch) and are fully-reloadable with Shell Shock’s custom reloading dies.
- Have been tested successfully by customers to pressures over 70k psi.
- Eject cool to-the-touch and can be picked up with a magnet.
Seismic ammo is taking conventional ammunition in a different direction. We believe a projectile with more mass traveling at subsonic velocities (900-1,000 fps depending on barrel length) is more effective than a lighter weight projectile traveling at a higher speed. Our 185gr 9mm +M ammo is now available and we have other offerings coming soon.
The projectile weight was right on the money with the bullet weight coming in at .422 ounces or 184.65 grains.
Seismic Ammo Subsonic 9mm FAQ
Why do you use NATO instead of SAMMI specifications on your 9mm 185gr?
- We chose to use NATO because of the ShellShock™ cases which are stainless steel. SAMMI spec for 9mm calls for a conformal transducer to be used on the case itself and is designed for brass cases. NATO measures the pressure at the case mouth and doesn’t factor the case material in its measurement.
Is your 9mm 185gr +P or +P+ rated?
- Since we use the NATO spec there is no +P or +P+ standard.
Will the stainless cases hurt my gun?
- No, according to ShellShock™ these cases are functionally less abrasive than brass, self-lubricating and corrosion resistant.
What is the average velocity of your 9mm 185gr?
- The velocity typically ranges between 900-1,000 FPS depending on barrel length. We recommend using a full-size pistol or carbine for optimum expansion and performance.
Will your 9mm 185gr work in my gun?
- We have tested our 9mm in multiple platforms and have yet to find anything that will not fire the round and cycle the firearm. However, we do recommend that you use a full-size pistol or carbine for optimum performance and velocity. Also we do not recommend our 9mm 185gr ammo for H&K™ USP, P2000, P30, or VP9 platforms. The MP5 performs well using the ammo.
Shooting The Seismic 185gr 9mm Ammo
I only have about 100 rounds of the Seismic Ammo down the barrel (it arrived yesterday afternoon) but all of the rounds functioned flawlessly in both the GLOCK G19 MOS and the H&K SP5.
Using the Labradar (thanks again for the loan, guys) I wanted to check velocities out of a standard pistol barrel and a carbine length barrel.
- Temperature: 80 degrees
- Humidity: 70%
- Pressure: 29.65 inHg
- Target distance: 25 yards
GLOCK G19 MOS (4”)
H&K SP5 (9”)
The measurements matched the expected velocities almost perfectly with the standard deviation being a bit tighter in the GLOCK than in the SP5. Shooting the Seismic Ammo is about as quiet as it gets when using the SilencerCo Octane 45HD and Omega 9K. Impressively quiet.
Honestly, with the 185gr bullet weight, the ~950f/s velocities and reliable cycling, the only reasons I could find against running the Seismic Ammo subsonic 9mm in your suppressed pistols and carbines is cost. Bumping up against $1.50/round, it’s definitely at the top of the 9mm price spectrum. The advantages over other heavy 9mm rounds is that the bullet appears to expand very nicely and the two-part case allows for higher pressures which results in higher velocities compared to brass cased ammo. The Seismic Ammo bullets appear to be coated lead which could lead to buildup inside suppressors compared to jacketed rounds, but cleaning every 500 to 1,000 rounds should alleviate most concerns.
Thanks for reading. Be safe, have fun and we’ll see you here next week for another edition of TFB’s Silencer Saturday.
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