A compensator is a device that attaches to the muzzle of a firearm to reduce muzzle rise by redirecting escaping gases from the barrel in a certain direction, either upwards or to the sides. I decided to purchase one from Parker Mountain Machine during their Black Friday Sale for my full size Walther PDP Pro SD. This compensator is made out of 7075 Aluminum and anodized in black. It threads on to the PDP Pro’s 1/2 x 28 threaded barrel and is secured with Loctite, and has a single upwards facing port.
Appearance: This compensator fits flush with the PDP and the lines of its design could easily make it mistaken for a factory part if PMM’s logo wasn’t imprinted on the top. From the pictures, it looks like the compensator might be touching the pistol’s muzzle, but edges are beveled and do not actually come in contact with the muzzle.
Installation: A major difference between PMM’s compensator and those of competitor’s is that the compensator has to be Loctited onto the barrel, without a set screw. Installation requires the use of included shims to get the positioning just right on the barrel. I used a vise with soft grips installed, and also used PMM’s optional “Muschi” block which made the installation easier. However, it did take me a couple of attempts to get it on just right since I underestimated the timing of the shims.
Performance: Having installed a ZRT 13lb spring and brass guide rod simultaneously, it’s hard to judge the effects of the compensator on its own, but follow up shots had less felt muzzle flip. The gun overall shoots a lot softer, which is probably mostly due to the lighter recoil spring. PMM states in its product description that this product reduces muzzle rise by 30-35% using 115 grain UMC ammo, and from my experience I have no reason to doubt this. PMM also lists in its product page ammo that is recommended and not recommended for use with this product. Besides what is listed for recommended ammo, I did use Sellier and Bellot 124 grain ammo which worked flawlessly with the PMM comp.
Overall, I found this to be a worthy upgrade to a PDP. Its lines complement the PDP’s perfectly, and performs as promised. If you plan to run a suppressor, I would probably recommend the Harrington Arms comp, since the PMM comp has a semi-permanent installation since it’s secured on to the barrel with Loctite. Removing it would require added heat to loosen it. I did remove it once, but had to boil the assembly in hot water in order to unscrew it. This should be considered since you will not be able to remove the barrel from the slide easily after installing this compensator.