Shotgun Muzzle Devices

CRMD vs. OBMD : how and when to use each

The JK Armament 195 series of 12 gauge shotgun suppressors has two primary mounting options: CRMD and OBMD. CRMD stands for choke replacement muzzle device. OBMD stands for over barrel muzzle device.


If you are looking to suppress a shotgun that uses interchangeable chokes, go with a CRMD. Your existing chokes screw into the inside of your barrel, and this is how you control your shot pattern constriction level. Our CRMD will simply screw into your barrel in place of your choke tube and will then act as a quick attach muzzle device onto which your JK 195 suppressor attaches.

If you own a shotgun that isn’t threaded for choke tubes, which is the majority of tactical and self-defense style shotguns, we recommend using our OBMD. This likely means you’ll have to get your shotgun’s barrel threaded, which is a service we offer here at JK. An OBMD installed on external threads offers a shorter mounting system compared to the CRMD, and it’s also more robust.

Shotgun Threading & Muzzle Devices from JK Armament Suppressors on Vimeo.

How to use ‘em:

In either case, since it’s the Choke Cap at the very muzzle end of the JK 195 suppressor that controls shot pattern constriction, you’ll have full, rapidly-swappable choke levels available by simply exchanging Choke Caps. As its primary function is to act as a quick attach mount for your 195 suppressor, your CRMD or OBMD should remain “permanently” installed on your barrel.

In fact, unless you’re planning on moving one CRMD/OBMD across multiple shotguns (it’s far faster and easier to have one pre-installed on each of your guns, instead!), we’d recommend using a removable thread locker to lock it in place.

Example Build 1
Example Build 2
  • 155 Series
  • HD base tube
  • Baffles:
    • 1x .30 cal HD Rifle
    • 4x .30 cal PRO Rifle
    • 5x 9mm LT Pistol
  • LT Extension Tube
  • End Caps:
    • 1x .22 cal LT Flash Hider
    • 1x .30 cal LT Compensator
    • 1x 9mm LT Flash Reducer
  • Mounts:
    • 1x PRO QA Taper Mount
    • 1x 1/2x28 Thread Mount
    • 1x 5/8x24 Thread Mount
    • 2x .22 cal Bald Eagle
    • 2x .30 cal Bald Eagle
    • 1x 9mm Bald Eagle
    • 1x 1/2x28 Pistol Booster

With this build I can suppress every .30 caliber and smaller rifle and every 9mm and smaller pistol in my collection. Whether I’m running my AR-15 or AR-10 hard – even full-auto – or I’m on a spot-and-stalk hunt with a lightweight bolt-action rifle, or I’m plinking or varmint hunting with a rimfire rifle, or I’m shooting pistols and pistol caliber carbines in 9mm or smaller, this one suppressor can be configured so it’s ideally suited for each and every one of those things and more.

Heck, if I also owned a 45 ACP pistol and/or a 458 SOCOM rifle or a .45 cal lever action I could add 5x .45 cal LT and/or PRO Pistol baffles and have those guns covered, too!

  • 105 Series
  • LT base tube
  • Baffles:
    • 1x .22 cal HD Rimfire
    • 6x .22 cal LT Rimfire
    • 6x 9mm LT Pistol
    • LT Extension Tube
  • End Caps:
    • 1x .22 cal LT Flash Reducer
    • 1x 9mm LT Flash Reducer
  • Mounts:
    • 1x 1/2x28 Thread Mount

With this build I can suppress all of my rimfire rifles and pistols plus anything in 5.7x28mm. It’s also a Mission Configurable 9mm pistol and PCC suppressor that’s capable of being run in a full configuration for training on the shooting range and a short configuration for concealed carry. It’s so lightweight that it doesn’t need a booster!