Suppressor End Caps: What they are and how to use ‘em

JK Armament 105 and 155 series suppressors feature a swappable End Cap. In keeping with our Mission Configurable design philosophy, we offer quite a few End Cap options! Here are some tips for choosing the correct one(s) for you.


Our end caps are available with a bore hole diameter sized for many different calibers, from .22 cal on up to .50 cal. Matching the bore size to the caliber you’re shooting will offer the best possible sound suppression performance.

For instance, if you’re shooting a SBRX .30 Cal suppressor on a 5.56 AR-15, it will be quieter with a .22 Cal (for .223/5.56) end cap installed than it will be with a .30 Cal end cap installed. This is because a bore size closer to the bullet size means capturing and controlling more of the combustion gasses, which is the whole game in sound suppression.

That said, there’s nothing wrong with using an end cap with a larger bore size than necessary. For instance, shooting 9mm through a suppressor and end cap sized for 45 ACP. BUT!…don’t get this backwards. You cannot shoot a larger caliber through a smaller caliber end cap and/or suppressor – the bullet won’t fit through the hole! Whatever bore size the end cap and/or suppressor is rated for represents the maximum caliber that can be shot through it.


We make end caps in flash reducer, flash hider, and compensator styles.

  • The flash reducer end cap is the minimalist version. It adds the least amount of length and weight to your suppressor. Small cuts around the bore aperture provide for a bit of muzzle flash reduction.
  • The flash hider end cap has three prongs extending from around the bore aperture. This helps to mix combustion gasses with the atmosphere and greatly reduces visible muzzle signature.
  • The compensator end cap reduces recoil and helps maintain a steady muzzle for faster follow-up shots. It’s a really good looking design with practical benefits.


We offer end caps in LT, PRO, and HD materials. That’s 7075 billet aluminum, Grade 5 titanium, and 17-4 stainless steel, respectively. Choose your end cap material based on the balance of weight and durability that’s right for you, your firearm(s), and your planned rate of fire. In the vast majority of cases we recommend LT end caps.

Quickly and easily swapped with no specialized tools required, it’s a great idea to own a small collection of end caps to match your collection of firearms and to match each mission!


Age Verification



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!