Pistol Comps 101

Lets get a few things answered as I have seen quite a few misunderstandings about compensators floating around.

Q: What is the difference between a ported pistol and a compensator?

A: A ported pistol works by machining holes or ports in the barrel of the pistol. These ports vent the gasses early that are pushing the bullet down the bore of the barrel. This does a few things. First, the main reason ports are used is to reduce the energy used to cycle the slide. Think of it as using a 3” barrel on a 5” full mass slide or lowering the powder charge of your ammunition. As soon as the bullet passes the ports some of the gasses behind it are vented to atmosphere reducing the energy driving the slide rearward and the velocity of the slide. This can be observed in the ejection pattern of the pistol looking lazier than a non ported pistol. A slower moving slide with less energy will not transfer the same amount of force on the shooters wrist, therefore reducing muzzle flip and felt recoil (as long as proper shooting techniques are employed).

Compensators on the other hand work off of a different set of principles. Compensators primarily work using Pascal’s law which stated that Force=Pressure X Area. The way a compensator works is by allowing the same gasses pushing the bullet down the bore of the barrel to push on the forward wall of the compensator and generate a force on the barrel that is opposite to the direction of slide movement and recoil. This will rob the slide of some of the energy that is used to cycle to the rear and therefore may also slow the velocity of the slide. Contrary to the popular misconception, both porting and compensators DO NOT primarily work by redirecting gasses upwards to generate force counteract muzzle flip. The gasses would need a surface area to push on in order to do so and atmosphere doesn’t provide enough resistance. The main reason a compensator may have top ports is to maximize the surface area of the baffle wall effectively generating more forward force on the barrel. This in turn fights rearward slide movement and rearward forces generated on the shooter. We have tested this using prototype comp with ports aiming downwards. The compensator still worked the same. We just kicked up a lot of dirt from the ground and put a lot of soot on our weapon lights.

This picture captures the gasses as they are pushing forward on the compensator and ultimately the barrel.

Q: Do I need to change my recoil spring when running a compensator?

A: Most likely yes. That is if your compensator is actually doing anything significant. On a Browning type action pistol like Glock’s, M&P’s, and many other modern pistols, the slide movement to the rear (against the recoil spring) unlocks the barrel to cycle and pick up the next round from the magazine. A well designed compensator will generate enough forward force to make it difficult for the slide to unlock the barrel as it moves to the rear. This is the reason why you would most likely need to lower the weight of the recoil spring on your pistol when you run a compensator. The recoil spring must be matched with the weight of the slide and the forces it encounters during cycling to achieve reliability. Here is the point. If the compensator on your pistol runs with any ammunition without any changes to the factory recoil mechanisms, then it isn’t doing much of anything for you to minimize muzzle flip and felt recoil. You pretty much have a fancy thread protector. Of course when changing anything about how the gun behaves you should thoroughly vet its performance before ever considering it to defend your life or the lives of others with it. A compensated gun with a properly tuned recoil system can absolutely be reliable enough to carry and use for self-defense.

Our Nameless Arms Kaminari Compensator for the M&P 9mm pistol.

As always if you have any questions don't hesitate to ask at namelessarms@gmail.com or on social media @namelessarms.

Happy Shooting!

-Nate K.

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