Redefining The Integrally Suppressed RifleThe Firearm Blog


Getting Quiet: Redefining The Integrally Suppressed Rifle

There are many suppressed rifles with permanently attached silencers on the market, but what exactly is an integrally suppressed rifle (ISR). When I think integrally suppressed, I think of the suppression system built directly into the barrel. A good example of this is the Curtis Tactical 9mm bolt gun that Pete reviewed for TFB’s Silencer Saturday. Let’s redefine the ISR in a way that still allows the suppressor to be used on other platforms.

Getting Quiet: Redefining The Integrally Suppressed Rifle

Thoughts on the Integrally Suppressed Rifle

About a year ago I was able to purchase a Daniel Defense DDM4ISR. Although it was a Gen 1, Daniel Defense quickly upgraded my baffle system to the Gen 2–which greatly increased the performance. Besides being a “Daniel”, this became the favorite (and most interesting rifle) in my collection. It was impressive enough that I wanted a second–but unfortunately could not justify the expense for another.

They say imitation is the sincerest form of flattery, and like many of you, I decided to build my own.  I initially wanted to get as close to the DDM4ISR as I could, but I ultimately departed from that pattern. As I began to go through the process of figuring out components, I came to my initial question: “what exactly makes it an integrally suppressed rifle?”  It turns out it is not quite as straightforward as I originally thought. Let’s start with the definition.


It would appear as though the industry standard for an ISR is a suppressor that is built-in to (or physically part of) the weapon. A nationally ranked shooter I spoke with was adamant that you could not detach the suppressor for it to be considered an ISR. So I got down to the bare bones. What is the definition? Integrally is defined as “essential or necessary for completeness”. What if the suppressor component is needed to function (back pressures and gas systems and physics, oh my), but can be removed? If it is necessary or essential, can I call it an ISR? Probably not, but you can make a good argument for it.

Integrally Suppressed Ruger 22/45

Integrally Suppressed Ruger 22/45

I think we can all agree for it to be an integrally suppressed rifle, the suppression aspect has to be built into the rifle. When I think of an ISR, I visualize a firearm with an oversized barrel and the baffles all hidden within. With the suppressor recessed in the handguard, you have that appearance. It’s certainly the illusion of an ISR. Why does taking the same setup (i.e. pinning and welding) magically make it an ISR?

Thoughts on the Integrally Suppressed Rifle

Thoughts on the Integrally Suppressed Rifle


To build my own ISR, I started with a stripped upper and lower. I found a deal on a KeyMod handguard (don’t hate; it was cheap and the DDM4ISR rocks the KeyMod) that would internally support my .30 caliber silencer. Since I had no intentions of mounting anything more than a set of simple covers on the rails, it was perfect.

  • Armspec stealth recoil spring
  • Ballistic Advantage .300blk 8.5 ” barrel
  • Velocity drop-in trigger
  • Griffin RECCE silencer
  • Spikes stripped lower
  • Unknown upper laying around
  • Strike Industries BRACE

If I have a 12″ handguard with an 8.5″ barrel, it clearly cannot be fired safely without the silencer attached. This is certainly “necessary for completeness.” I get excellent performance out of an 8.5″ barrel. The 12″ handguard gives me enough room to comfortably get a good purchase on the foregrip. It’s a great look with the functionality of having a recessed can inside the handguard. With that barrel length, I had to go with a pistol brace. Yes, I aware of current issues, but will stay out of that here.

Thoughts on the Integrally Suppressed Rifle

Thoughts on the Integrally Suppressed Rifle


The problem with most commercial integrally suppressed rifles is that the suppressor and barrel are the same – they are one-trick ponies. If you are new to the suppressor game you generally find yourself wanting to maximize the use of your can, the more firearms you can run it on the better.

Since I have not yet invested my retirement funds in tax stamp collecting, I am still in the “one can, many guns” camp.  This leads me to build guns around that can. I wanted another ISR, so I built my “ISR-ish”.  I’m currently helping a friend with a build that is based on absolute minimum gas blowback.

Don’t get me wrong, my Daniel Defense ISR is still one of my favorite AR’s and I shoot it as fast as I can feed it reloaded ammo. If you ever have the opportunity to buy one, definitely drop the cash! If not, you can still build your own ISR, if you agree that a detachable suppressor attached to a recessed barrel inside of a handguard meets this redefined category. With the added benefit of being able to move that can to another rifle.

Has anyone done a build like this?

Happy Holidays, and please be safe out there.

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