The current service-size, striker-fired pistol market is virtually overflowing with options. I feel for the local dealers who strive to stock even a few of each model from the big names. The past few years have seen what should have been attractive models from well-established players that simply couldn’t get traction with shooters in this hyper-competitive space. The Walther PDP is one of the few breakout exceptions; launched just five years ago, it quickly gained a following among competition, duty and other serious shooters.
I have personally used the PDP as one of my primary handguns in teaching, training and competition and have come to appreciate the attributes of the line. Available with full-size, 18-round-capacity or compact, 15-round-capacity frames and barrel lengths of 4", 4.5" and 5", PDP variants have been adopted by numerous law-enforcement agencies, the Pennsylvania State Police and, most recently, the German Special Forces as the P14.
Walther has expanded the PDP series with a number of special-edition “Pro” models in the past few years, offering features/modifications that appeal to its professional shooters or the aftermarket from its Arkansas-based U.S. headquarters. The latest are the PDP Pro-X PMM Full-Size and Compact models—the former of which I tested extensively on the range and the latter illustrated here—both consisting of the long accessory rail from the 5" models paired with a 4" slide and a 4.63" barrel mated to a specially designed compensator via 1/2x28 TPI threads—basically yielding 5"-barreled pistols. The Full-Size features a 20-round magazine while the Compact’s holds 18 and has a deeper floorplate assembly, making both guns the same height with a magazine in place.
The special models further incorporate a Walther-designed extended magazine well and utilize the Dynamic Performance Trigger from the company’s match models. The PMM in the model names is for Parker Mountain Machine, a shop specializing in aftermarket performance parts for popular pistols that collaborated with Walther on this model’s compensator.
The Pro-X PMMs arrange features in a new format but, at heart, are still familiar PDPs with near-full parts compatibility. The new Walthers share the same drop-safe, striker-fired action as the rest of the PDP line wherein the striker is fully tensioned upon cycling and the trigger bar depresses a safety plunger well into a deliberate trigger press to free it. The well-placed magazine-release button and bilateral slide releases are identical to those on the stock PDP, and the Pro-X models retain the aggressive SuperTerrain slide serrations that “swell” from the slide contour to provide deep, sure purchase.
More Than Adequate Compensation
Compensators seem to be having a moment in the handgun world. Marine officer Richard Cutts first applied for a patent on his “climb arrester” device 100 years ago, quickly gaining fame when it was added to the end of the Thompson submachine gun to tame recoil. Just a few years later, Texas gunsmith Hyman Lebman added the Cutts device to full-automatic conversions of the Colt M1911 to help keep the muzzle down on pistols used by noted gangsters. The Cutts compensator later hopped to shotguns where it was quite popular both before and after World War II, but shooters didn’t clamor for them on handguns until more recently. I believe that early compensators showed up first on .22 rimfire target pistols of all things, and, by the 1980s, had become a de facto requirement on highly modified centerfire race guns in several sports. It is just in the past few years that compensators have been widely considered in the crossover space between duty and regular shooters looking for more performance.
The Walthers’ aluminum, single-port compensator is threaded onto the extended 4.63" barrel and matches the angles and contours of the PDP slide, nestling in to form a single unit as the barrel returns to battery and locks up. The Parker Mountain Machine compensator takes the gases attendant to firing and re-directs a portion upward to counter muzzle rise during the firing cycle. As the gases act on the forward baffle, the comp also somewhat resists the rearward motion of the pistol. These two vectors are needed for any recoil-operated handgun to cycle, so there is a balance that must be maintained. When aftermarket threaded barrels and compensators became a customization trend a few years ago, many shooters found out the hard way that a comp can be “too” good, making an otherwise reliable pistol highly sensitive to ammo selection and/or requiring spring adjustments.
Walther did its homework with the Pro-X’s compensator. The single port is effective but leaves a margin of error wherein the PDP maintains the reliability across a broad variety of ammunition types. And this is maintained with the standard recoil-spring assembly. I fired a dozen different loads—from underpowered, low-cost range ammunition to +Ps—with perfect results from the Full-Size model. While Walther’s website does list a few of the popular mild-range loads to avoid for optimal results, as the company can’t ensure that each shooter will attend to proper lubrication and grip the pistol well, I did, however, fire several loads from the “avoid” list without issue.
I generally view 9 mm Luger ammunition in four levels of increasing recoil. First are the popular lines of soft-shooting range ammunition, which tend to run at the low end of the velocity window. Next are the loads that run more toward the typical velocity window for their projectile weight. The third tend to be defensive loads that operate closer to the pressure limits for their weight with slightly higher velocities. Lastly are the loads in the SAAMI specifications for +P, which adds another 3,500 p.s.i. to the limit and boosts velocity further. I can usually feel a difference between loads at each of these levels. My subjective impression was that the Pro-X “converted” loads to one bracket down. In other words, +P felt and performed more like hot standard-pressure loads, hot standard-pressure loads felt more like standard FMJ and standard FMJ felt more like the mild range ammunition.
I shot the Pro-X head-to-head with my favored 4.5"-barreled PDP on several tests using both standard-pressure (American Eagle FMJ) and +P (Black Hills JHP) loads. The difference in rise was immediately apparent, but that didn’t always translate to a difference in speed. I found that I was often using a similar tempo, just delivering much tighter groups with the Pro-X. As I got more used to the Pro-X PMM and gathered more data, I found that on moderately challenging targets, say a rapid-fire string to a 4" target at 5 yards or a rack of 8" plates at 15 yards, there was a consistent 5 hundredths advantage to the compensated Walther. For example, the time between hitting two plates might be 0.4 seconds with the PMM model and 0.45 with the stock gun. That roughly 10 percent advantage for each shot adds up to a large margin over the course of multiple shots.
Five hundredths is right at the edge of what many shooters can reliably perceive and “feel” in a time difference. However, I also find that when many shooters miss moderately difficult targets, the time it would have taken to correct whatever the error was in execution often begins at about a tenth of a second. So, the five hundredths advantage for the compensator provides a buffer toward better execution. Visually just having the dot or front sight moving less will give many shooters more confidence in their shooting; I found this to especially be the case when shooting with a single hand.
I appreciated that the compensator took the edge off of recoil but left the overall feel familiar in the hand. I also was pleased to find that the pistol’s blast and report were unremarkable. Some pistols are just “barky” in general, and some comps can re-direct noise in a way that affects the shooter. In this case, I found the noise surprisingly and pleasantly mild. I fired the Pro-X PMM from retention while fully against a target with the pistol indexed tightly against the side of my chest. The upward gases were noticeable against my cheek but not painful. The Pro-X PMM’s industry-standard 1/2x28 TPI muzzle threads mean that the buyer has the option to remove the compensator should he or she wish to use the pistol uncompensated, shoot suppressed or explore another type of compensator.
Trigger, Accuracy & Security
The Pro-X PMMs ship with adjustable polymer sights, and the pistols are dovetailed to accept aftermarket sights of the Glock pattern. The factory sights are adequate, but these are models likely to be outfitted with optics in the great majority of cases. The Pro-X models ship with an optic cut covered by a plate, and each pistol includes a voucher for an optic-mounting plate of the buyer’s preferred footprint. I mounted an RMR-pattern plate and then a Holosun 507 Comp optic.
The new Walther uses the company’s popular Dynamic Performance Trigger (DPT). This trigger assembly has been very popular as an upgrade to the standard PDP and has been featured in several of Walther’s previous match and limited-edition models. Visually, the DPT replaces the curved polymer trigger shoe with a straight aluminum shoe. The tab safety is retained, and the trigger breaks at nearly 90 degrees. But the differences extend beyond the visual; the trigger feel is in the general PDP family—with some distinctions. The take-up is significantly reduced (by roughly 0.2") and there is a rather distinct, almost-crisp break. Total weight of the break on my test gun was 5 lbs., 3 ozs., with the weight at the break after take-up measuring about 3 lbs., 8 ozs. The upgraded trigger provides just enough take-up and weight to add a margin of safety. Makers can (and certainly have) made triggers with less travel and a lighter break, but their broad applicability suffers as they have accepted risk and removed any margin for stress or rough handling.
Triggers in the striker-fired-pistol world have come leaps and bounds during the past decade, and there are numerous models with genuinely good triggers. “Best” is subjective, but in almost any discussion, whether the speaker is a professional or relative newcomer, the PDP trigger is often mentioned among the best in class. Yet as great as the stock PDP trigger is, I suspect that many, possibly even most, shooters will like the DPT even more. The great divide in triggers used to be between striker-fired pistols and the legendary M1911 platform. In comparing the Pro-X trigger to several of the double-stack 2011-style 9 mm Luger pistols I’ve handled from multiple makers, the Walther has a break that is arguably better than any of those stock triggers.
One notable feature on the PDP series is the stepped chamber in the barrels. This tighter seal at the case neck tends to produce a velocity boost for many loads compared to nominal velocities from that barrel length in other pistols. An extra 50 f.p.s. or so is helpful in a defensive pistol and is also useful in pushing more force into the compensator. I occasionally see people complain that the PDPs feel a little snappy to them, and I suspect that the extra velocity is perhaps part of that perception.
In the Pro-X models, the barrel is made in America by Walther due to its being threaded. German-made barrels are held in high esteem by many shooters, so it was rewarding to see the U.S. tube in the Pro-X shoot exceptionally well. Whatever combination of tolerances, materials and/or the stepped chamber, the PDPs tend to shoot almost unreasonably well. The PMM is the fifth PDP I’ve benched, and each of them have reliably cut 1.5" or smaller groups at 25 yards with ammunition they liked. During accuracy testing, I taped over the tight groups between strings, and the Pro-X stacked 10 rounds (two groups) of the Hornady 135-grain Critical Duty into only 1.52". On my most recent range trip with the pistol, I had just fired a clean 25-yard bullseye with the Speer Lawman 147-grain load and noticed my Wilson Combat reduced steel silhouette downrange. Backing off to what looked to be about 50 yards away, I estimated the hold and fired a group at the 6"x6" head of the target. Four of the shots piled into a group and one where I was less diligent struck the shoulder. Wanting to verify the distance, I grabbed the Leupold rangefinder, lased the steel and was doubly happy to learn that the target was actually 60 yards out.
The Walther’s aluminum magazine well cleverly attaches via the roll pin that secures the interchangeable backstraps. It fits securely and mates tightly while adding a blended funnel to give the shooter a larger margin for error in each cardinal direction on fast reloads. The magwell does prevent the use of stock PDP magazines and requires the extended basepads, which help to ensure positive seating. At the time this was written, Jens Krogh, of Walther marketing, told me that the company was increasingly seeing law-enforcement requests for extended magazine wells on pistols as an aid to weapon retention. The thinking is that the magwell helps lock the officer’s hand onto the grip and may assist in preventing the pistol from being stripped in a struggle over the gun.
Wringing It Out
I outfitted my sample Pro-X PMM Full Size with a Holosun 507 Comp red-dot and predominantly used it with a Surefire X300U weapon light mounted to the rail. The total system weight for such a capable package with 21 rounds of 9 mm was about the same as an empty, railed, steel, Government Model M1911, so it fits in the “purposeful/steady-on-target” bracket. I also tried the Walther with the new Phlster Floodlight 2 concealment holster. Yes, the Pro-X is large, but I’ve found the original Floodlight to have an uncanny ability to take many large pistols with attached lights and make them disappear comfortably. The new version of the holster is even better and was comfortable, fast and quite effective in concealing the Walther. In all, I fired about 2,000 rounds through the Pro-X PMM; there were no stoppages or bobbles. I wiped the pistol at about 1,200 rounds and lubed it lightly at 300- to 400-round intervals. The black-nitride finish is hard-wearing and still looks new. I could just begin to see some carbon collecting in the port of the compensator to show that it was getting appreciated.
Late in the testing period, I found a new replacement backstrap made by Kiral Defense and added it to the Pro-X. This required removing the magazine well and changed the feel of the grip to approximate that of a double-stack M1911. My XL glove-size hands immediately took to it. The Walther backstraps are small, medium and large, and for years, I have modified the large unit to give me more purchase. The Kiral backstrap has an interesting shape and some interesting features, and I like where the designers were going. For shooters who like the shape of the factory backstrap, several firms are offering compatible aluminum and brass replacements to add weight. Overall, the PDP enjoys much broader aftermarket support than many pistols, and Walther aggressively works with even small vendors to cultivate that leg up in the marketplace.
That Walther’s Pro-X PMM models provide a noteworthy amount of performance at a three-digit MSRP means they not only represent a solid value but are well-positioned to gain the platform more fans as the line expands and becomes more familiar. I have already used the new Full-Size PMM to teach several classes, and have found that some of my demonstrations on the more difficult drills were coming a little easier than usual. In fact, with their combination of recoil attenuation and match triggers—paired with the familiar PDP-platform controls—the new Walther PDP Pro-X PMMs almost make for an unfair advantage.
