Composition and assembly

On the exterior, it resembles the Walther P99, but it is somewhat smaller (75% of the P99's size) and its action chambers the rimfire .22 LR cartridge. The most noticeable exterior difference is the P22's slide mounted, thumb operated, ambi-dexterous safety and its external hammer. The P22 features a cast polymer grip-frame. Its slide and serial numbered frame receiver inserts are made from MIM (Metal Injection Molding) cast zinc alloy, its barrel consists of a rifled steel insert within a steel barrel sleeve, and its internal lockwork and fire-control parts are a combination of MIM cast steel and steel stampings.

The P22 can be purchased with a 3.4-inch short barrel, or with a 5-inch barrel which includes a barrel mounted weight compensator matching the profile of the slide (pictured to the right). The P22 was originally designed such that the two different length barrel assemblies could be easily interchanged, and "combo" packages including both barrels were offered for sale.

The P22 is offered in many different color variations of its polymer lower receiver. Black, Olive Drab, White, and Carbon Fiber are options. The slide assembly will either have a blue-black applied finish, or it will be finished with a nickel/stainless look.

Due to California's ban on Assault Weapons, the Walther P22 is not available for sale in that State. The gun was approved for sale only to be delisted after the California Department of Justice realized the pistol had a barrel that was threaded (threaded barrels on semiautomatic pistols in California are a characteristic which makes them illegal under the state's ban on so-called assault weapons). P22's that were sold in that state had to either be removed from the state or returned to the manufacturer for a modification ensuring that the original barrel extension purchased with the gun is permanently installed and cannot be removed without ruining the barrel assembly, or the handgun, or both. In some countries, like Finland, the original 3.4 inch short barrel causes the P22 to be classified as a concealable firearm, making the 5 inch target barrel the only available option for normal recreational shooters.

Operation

The P22 may be fired double action for the first shot from a hammer-down condition, and operates as a single action on all successive shots. The hammer can only be de-cocked by pulling the trigger, as this particular handgun does not have a "decocking" lever.

The P22 operates on the blowback method of semi-automatic operation. Under this approach, the pressure generated by a firing cartridge is contained by a combination of the inertial weight of the slide assembly and the force of the recoil spring. There is no "locking" mechanism. The strength of the recoil spring and the weight of the slide are such that the rearward force of the firing cartridge will not open the action until the projectile has left the barrel and the pressures have dropped to safe levels.

As with many semi-automatic pistols, the P22 is equipped with a magazine disconnect that prevents the trigger from operating on the sear mechanism unless a magazine is actually inserted and locked into the weapon. The magazine disconnect on a P22 works by utilizing a strong spring to apply downward force against the trigger bar, such force being sufficient to overcome the action of the relatively weaker trigger spring which interacts with upward force on the same bar. When a magazine is not locked into the weapon, the downward force of the stronger magazine disconnect spring causes the trigger bar to pass beneath the internal lockwork of the weapon when the trigger is pressed. Once a magazine is fully inserted, however, an actuator surface on the front of the magazine pushes against the magazine safety. This overcomes the magazine safety's strong spring, and thereby serves to allow the trigger bar to spring upward under the force of the less powerful trigger spring. When this occurs, the trigger bar is in a position where it engages the lockwork when the trigger is actuated. An added side effect of the interplay between the strong magazine disconnect spring and the magazine itself is that the magazine will "spring" out of the grip of the weapon very vigorously when released.

Safety

The P22's slide mounted safety, when engaged, performs two functions. First, it serves as a "hammer block" by rotating a portion of the metal surface of the safety into a position that interferes with the hammer's contact with the firing pin. Second, it acts as a "firing pin lock" by rotating a portion of the safety into a notch on the underside of the firing pin, thereby inhibiting forward movement. The P22 safety does not prevent sear or trigger movement, and (as noted), it does not provide a hammer drop function. If the hammer is cocked when a P22 is been placed on "safe," the hammer will continue to remain cocked and will only fall if the trigger is pressed. If the safety is on, the hammer will strike the safety instead of the firing pin and, therefore, fail to fire. Good safety practices generally counsel against relying on mechanical safeties and such a method of decocking should only be used when the firearm is unloaded and pointed in a safe direction.

The P22 utilizes an additional, passive, safety mechanism to protect against accidental discharges in the event the weapon is dropped. When the action is closed, a small metal button on the underside of the breach block is actuated by an arm surface extending from the sear. In this state (whether or not the hammer is cocked), the firing pin is mechanically blocked and cannot move forward to strike a cartridge rim. When the trigger is pressed, the sear moves downward in such a way as to move from its interaction with the firing pin safety, which in turn springs downward under the force of a captive spring within the breach block. This disengages the firing pin safety, allowing the firing pin to move and the weapon to fire.

Firing pin

The firing pin on a P22 is "inertial." That means when fully depressed by the weapon's hammer in its "down" or at-rest position, the firing pin does not actually reach the cartridge rim. It can only fire the cartridge by way of inertial energy after it has been hit vigorously by the full force of a cocked hammer. For this reason, it is not abnormally dangerous to have the hammer down on a P22 with the safety off (as was the case historically with most single action revolvers and some semi-automatic pistols). A strike to the hammer in such a situation will not fire the P22. Even so, the operating manual for the P22 cautions users to diligently apply the manual safety except when ready to fire the gun. This aspect of the firing pin also adds safety to the manual method of decocking that is required to be used with this firearm, though, as mentioned, it is wise to keep the firearm unloaded and pointed in a safe direction when decocking.

Due to the inertial firing pin, the P22 should not be "dry fired" extensively during aiming practice. Doing so not only risks deformation of the chamber face, but the repeated forward action of the firing pin into and beyond the space normally occupied by the rimfire casing will eventually distort the firing pin spring. If this happens, the firing pin will no longer return vigorously to its default at-rest position at the extreme of its possible rearward travel within the breach block. This could result in less or none of the firing pin's rear surface protruding beyond the rear of the breach block for impact by the hammer.

Suppressed P22

The Walther P22 is easily converted to accept a sound suppressor. Many dealers sell the firearm with an adaptor new in the box. The adaptor allows a number of rimfire suppressors to be used in conjunction with the firearm. Installation is quick and does not require the use of any special tools. Additionally thread protectors are available to safeguard the threads on the ataptor. The adaptor can be purchased from a number of internet vendors, including Yankee Hill and Machine.

P22 Modifications

Here are a few modifications available if you are having trouble with your firearm.

(0) Disassemble the gun. Take off the slide; pound out the 2 roll pins holding the action in the plastic lower. You may need to unscrew the two halves (sideplates) of the action to do some things.

(1) Ditch the stupid mag safety. I removed part #23, and the gun actually works like a normal handgun.

(2) Ditch the slide stop spring. This kept slipping out from under the slide stop and making the last-round-hold-open nonfunctional. In the hundreds of rounds I have shot since then, the mag spring has been plenty strong enough to lock the slide back.

(3) Tweak the extractor spring. Push out (mine is just held in place by the tension of the extractor spring) the pin holding in the extractor. Gently stretch the extractor spring with some pliers. Exceeding the elastic limit of the spring does weaken it in theory, but I haven't noticed any ill effects yet. I get much more reliable extraction with this mod. I can't remember the last time I had an FTE, but I had them all the time before doing this.

Other good fixes:


1. Take a dremel with a tapered stone and just "touch" the edges of the back of the chamber. Its got a sharp edge on lots of guns, which impacts feeding. Just polish and slightly chamfer the edge.

2. Dress the ejector face. You want to scale back three of the four corners on the face so that it ejects sharply to the side, instead of back into your face.

3. Add a trigger stop. I put mine right at the very bottom, in the frame of the gun and not on the trigger itself. Works great. The P22 is so light that any tiny amount of overtravel by the trigger will throw off point of aim. My grouping is MUCH MUCH better since I did this. Some folks use rubber O rings around the trigger for the same effect (nice non permanent mod).

4. Slightly (very slightly) radius the part of the hammer that rubs against the slide during the forward chambering / into battery phase of the cycle. You'll feel a point where the hammer's edge catches on the place where the safety bar and the steel insert in the slide meet. You want to round and smoothen the hammer to keep this "hang up" from happening. Don't remove too much material, or the hammer won't lock back and you'll have a double action only Walther. (alternatively, maybe that's what you want -- hey, to each is own).

5. Add a little bit of cornstarch to the threads of the barrel nut, fire 2 mags, then cinch the barrel nut just a "hair" tighter. Poor man's loctite and it lets you remove things if need be without heat.

6. Remove the firing pin. You'll see that the front has both the machined "dash" shape of a rimfire pin, and ALSO a square flat area that hits the breach face and prevents over penetration. Well, you can take just a HAIR of material off of that square part to give deeper firing pin hits. Especially once you've got some milage on the gun, the hammer spring may not have enough oomph to light off some brands of primer in D.A. (where the hammer throw is shorter).

7. This one is VERY IMPORTANT: Take a dremel and radius the FRONT edge of the two ears that stick up from the action and interact with the slide as disconnector ears. That piece is SHARP from the factor and really beats the hell out of the indentations on the slide. You want to make that into a "rounded" nub by removing the sharp edge from the front, top, edge of those little ears. (take a look at how they interact with the slide and you'll get the right idea).