Dissecting The P938

The SIG SAUER P938 is a well made 9mm in a small package, built for ruggedness and concealability. It’s a six shot, mechanically locked, short recoil operated, semi-auto, single action only pistol. We’ll start with the P938’s operating characteristics. The slide lock is pushed up by the magazine follower after the last round is fired from the magazine, locking the slide back. The automatic firing pin safety blocks the firing pin unless the trigger is pulled.

The hammer has a safety intercept notch (quarter cock notch) keeping the hammer off the firing pin if desired. The disconnector keeps the hammer from falling when the slide is out of battery and not fully closed. The pistol has high contrast drift adjustable sights with a double white dot rear and a single white dot front.

There are six different rear sight heights available from the factory and each increment moves point of impact two inches at 25 yards and five different front sight heights yield one inch of change. The thumb safety up (on) blocks hammer movement either cocked or uncocked. The slide can be cycled when the hammer is cocked and the safety engaged. With the hammer down (uncocked) and the thumb safety engaged, the slide is blocked and cannot be cycled. The pistol has a three-inch barrel.

The pistol featured in this article has a black, hard anodized aluminum frame and a stainless steel slide weighing 16 ounces unloaded. There are several different configurations of the P938, differing mainly in grips, sights, and regular or stainless steel slides. P938 disassembly also applies to the P238 .380 ACP as well. To field strip, remove the magazine and cycle the slide to unload.

Pull the slide back to the disassembly notch (a half-moon slot in the slide) and push out the slide stop right to left out of the frame. Wrap a hand around the grip and slide to hold back the slide while pushing the slide stop out with the other hand. Get a good grip as the recoil spring is stout! Remove the slide off the front of the frame and hold it in one hand, pull back on the recoil spring and guide slightly, and lift them out of the slide while restraining the guide and recoil spring.

Remove the barrel and the four grip screws right and left. The screws are metric M4.5. The pistol is now field stripped for routine cleaning and lubrication. Don’t completely disassemble the slide unless repair is necessary. If so, drift out the extractor roll pin from the bottom through the top of the slide. Remove the roll pin punch while restraining the extractor and its very stout spring. Remove the extractor and spring.

Push in on the firing pin with a small pin punch and release the firing pin stop down out of its slot while restraining the firing pin and spring. Remove the firing pin and spring. Make note of the position of the rear sight before drifting it to the right with a nylon or other nonmarring drift punch. Drift it only as far as needed to remove the firing pin block spring and firing pin block from the top of the slide. Also make note of the position of the front sight before drifting it out.

Reassembly of the slide unit is in reverse with a few notes. When reassembling the firing pin and spring, the small end of the spring goes on the firing pin first. Install the firing pin block first and orient it so it rests on the slide shelf in its slot, then place the spring on top of it. Be sure to push the spring down as you drift the rear sight back to its original position. Place the barrel in the slide. When placing the recoil spring on its guide, the tighter end of the spring goes on first.

When placing the spring and guide into the slide, I utilize a small rod through the guide hole in the front of the slide to keep the spring from kinking. As you put the guide into

the spring, remove the rod a little at a time until the guide and spring is in place in the slide. This makes it easier and prevents damage to the spring. Kinked recoil springs lead to malfunctions. Complete disassembly of the frame is also only to be done for repairs. Make sure the hammer is eased forward into the fired position. Remove the thumb safety by rotating it clockwise while restraining the safety plunger and its spring.

Remove plunger and spring, then rotate the safety clockwise and remove right side first (ambidextrous safety) and then left side (with shaft). Remove the mainspring housing pin left to right. Pull down on the housing slightly to remove spring tension on hammer. Remove the hammer, hammer strut, mainspring, and mainspring housing pin lock out the top of the frame. Do not remove the hammer strut pin unless repair is required.

Drift the sear pin out left to right and remove the sear and ejector out the bottom of the frame. The sear spring is attached to the mainspring housing. Do not routinely remove the spring from the housing. If necessary, simply detach it from the stud and slot in the housing. Disengage the top of the spring from the trigger bar and remove the housing and spring down out of its slot in the frame. To remove the magazine catch, push in on the catch and turn the lockscrew counter clockwise until it locks.

Turn the screw clockwise to disassemble the lock and spring from the catch. Do not remove the trigger assembly unless repair is necessary. The trigger pin is a press fit and is in tight. If necessary, drift out the trigger pin and remove the trigger assembly down and out of the magazine opening. Trigger assembly can be further disassembled by drifting out the trigger bar pin and removing the trigger bar and trigger bar spring. Remove the disconnector down out of its slot on the left side of the frame.

Note, it sits on the trigger bar and is powered by the trigger bar spring in operation. Pry the slide stop spring out of its slot in the top left side of the frame. The frame is now completely disassembled. Reassembly is in reverse with a few notes. The trigger assembly can be a tricky maneuver. Slide the assembly up through the left side of the grip opening and into place against the trigger bar spring tension.

Once the trigger pad hole is in line with the trigger pin hole in the frame, drift a small pin punch through the entire assembly and out of the other side of the frame. The trigger pad actually pivots backward and upward as the trigger is pulled. Drift the trigger pin in, removing the pin punch in the process. What makes this extremely difficult is that the trigger pin is a press fit. Evidently, the factory thought this pin would move in firing and was determined not to let that happen.

Make sure the trigger assembly is functioning properly before proceeding. Capturing the ejector/sear is another tricky maneuver. There are two ways to do this procedure and both methods work equally well. Install the searspring/mainspring housing completely, making sure to clear the back of the trigger bar with the spring fingers. Remember, the spring fingers have to be behind the sear/ejector for proper function.

Using a small pin punch as a slave pin, place the punch through the left side of the frame and capture the ejector against the pressure of its spring finger, the one with the 90 degree bend at the top. In the first approach, place the sear in proper orientation (see schematic diagram) against its spring finger pressure and slide the small pin punch all the way through the other side of the frame. Check for proper operation of both the ejector and sear against their spring tension.

If all is OK, drift the sear pin in, replacing the pin punch and capturing the ejector/sear. Install the mainspring housing pin, securing the housing. The second method is to first install the ejector and sear, securing them with the sear pin and then install the searspring/mainspring housing, making sure to hold the spring fingers back. Then the trigger bar is cleared, allowing the fingers to settle behind the ejector and sear as the housing is pushed all the way in and secured with its pin.

The ejector finger, with the 90 degree bend, needs

1 Frame 2 Slide Stop 3 Thumb Safety 3A Ambi Left Thumb Safety 3B Ambi Right Thumb Safety 4 Barrel 5 Slide 6 Hammer 7 Firing Pin Stop 8 Magazine Catch 9 Magazine Catch Lock 10 Trigger Pad 11 Trigger Bar 12 Firing Pin to settle into the cutout at the bottom of the ejector and the sear finger has to bear against the back of the lower tang of the sear. Once again, check for proper spring tension against the ejector/sear.

Place the mainspring into its slot in the housing, making sure the main- 13 Disconnector 14 Hammer Pin 15 Hammer Strut 16 Extractor 16A External Extractor 16B External Extractor Spring 16C External Extractor Pin 17 Firing Pin Block 18 Slide Stop Pin 19 Mainspring Housing 20 Ejector 21 Recoil Spring Guide 22 Front Sight 23 Rear Sight SIG SAUER P938 (Speci ications subject to change without notice) 24 Sear spring 25 Mainspring 26 Right Grip Plate 27 Left Grip Plate 28 Grip Plate Screw 29 Safety Detent Plunger 30 Sear Pin 31 Trigger Pin 32 Trigger Bar Pin 33 Mainspring Housing Pin Lock 34 Sear 35 Recoil Spring 36 Firing Pin Block spring 37 Magazine Catch/Trigger Bar Spring 38 Safety Plunger Spring 39 Firing Pin Spring 40 Magazine 41 Mainspring Housing Pin spring housing pin lock is properly oriented on the bottom of the spring.

Place the hammer and strut down into the spring and line the hammer pin hole in the frame with the hammer. Slide the hammer pin in, left to right. If this proves too difficult to install, the hammer against its spring tension. Take out the housing pin and move the housing down slightly. After hammer installation, move the housing back into place, making sure the sear spring fingers are properly positioned against the ejector/sear.

Place the ambidextrous safety in its slot in the frame (both ends of the safety) and rotate it clockwise just above the hole in the hammer pin. Place the safety plunger spring and then safety plunger detent into the hole. At this point, I use a small cup tip punch to depress the plunger/spring down and rotate the safety down, capturing the plunger/spring. Note, this is a powerful spring when depressed and this assembly will go into orbit if it gets away from you.

Use a plastic zip lock bag to prevent this occurrence if you’re not comfortable with this maneuver or you will likely be ordering anew plunger and spring. Reverse the field strip instructions to put the slide unit back on the frame, making sure to depress the ejector when pushing the slide unit back completely. To disassemble the magazine, push the follower down with a blunt non-marring object (an unsharpened pencil works well), placing a pin punch in the fourth hole from the top to restrain the magazine spring.

Shake the follower to the top of the magazine and angle it out of the magazine body. Turn the magazine upside down and place its top against a workbench pad and pull the pin punch out. Remove the spring from the magazine body and clean appropriately. Reassembly is in reverse, making sure the smaller loop of the spring is on top, angled forward. The factory advertises the trigger pull between 7.5 to 8.5 pounds.

This particular pistol had a consistent pull of seven pounds and was very uniform through each round fired. Recoil is not much more than a .380 ACP, making this little, dandy 9mm, a very good choice as a small primary concealed pistol or as a back up. I would feel comfortable using this P938 for my own protection. AG