Disassembly and Reassembly of the Smith & Wesson M&P Pistol

"m I guessing you probably weren’t around back in the day when S&W first scored big with the military and law-enforcement communities with its Model 10 revolver’a sixround .38 Special. That was, after all, over 100 years ago, and even yours truly is not quite that old. Nevertheless, it was that venerable wheelgun that was the ancestral namesake of the newest series of Military & Police duty weapons. Of course, any similarity between the old and the new M&Ps begins and ends with the name.

Smith & Wesson’s first model in the new M&P series is chambered for the .40 S&W, packing 15-plus-one of this potent round. Coming up, if not already here by the time you read this, is a 17-plus-one in 9mm, a 15-plusone in .357 SIG, some compact models and, rumor has it, a .45 ACP is looming just beyond the horizon. The M&P measures a neat 7.5 inches long, 5.5 inches from the rear-sight top to grip-frame bottom, with a 6.4inch sight radius. Empty weight is a mere 24-1/4 ounces.

Width of the grip ranges from 1.168 inch (small) to 1.279 inch (medium) to 1.393 inch (large), by means of instantly interchangeable grip panels. Among other features area polymer frame with a rigid embedded stainless-steel chassis, and a through-hardened-stainless-steel slide and barrel with black Melonite finishes boasting a surface hardness of 68 HRc.

The M&P also features an ambidextrous slide stop, a sear-deactivation lever, a reversible magazine catch, an internal locking system, and an optional magazine disconnect. The magazine disconnect may or may not appear on an M&P brought in to you for a clean up or repair, but I’ll be showing you how to spot the presence of the disconnect anyway. So let’s take this thing apart and see what surprises it holds.

Field Stripping With the magazine out, the chamber empty, your finger outside the triggerguard, and your eye protection in place, grasp the slide by its rear serrations and draw it back. Press up on the slide stop, ease the slide forward to engage it, and lock the pistol open. Check again to ensure you’re dealing with an empty chamber. Every M&P carries a tool in its grip frame. Give the tool a quarter turn in either direction and withdraw it from the frame.

You’ll be using it right away to push the sear-deactivation lever down into the magazine well. Rotate the takedown lever on the left side of the frame clockwise. Get a grip on the top of the slide, move it slightly to the rear, and then pull it forward to

The cutout in the top of the slide serves as a loadedchamber viewing port. The Tshaped object near the grip is the integral frame tool. get it off the frame. Now invert the slide. Remove the recoil spring by compressing it away from its barrellug notch and then lift out the barrel. Spotting the Safety Features Or Lack Thereof When you lock the slide open during field stripping, look down through the ejection port into the magazine well.

If you see a small lever sticking out down there, the pistol has a magazine disconnect to disengage the trigger linkage and prevent firing when the magazine is out of the pistol. If there’s no small lever, then there’s no disconnect feature. All M&P pistols will at least have a single thumb safety on one side to block the trigger when the safety is in the upward position, and some will have an ambidextrous manual thumb safety.

Regardless of the type of safety levers or their location, when the thumb safety is "on," the slide can be opened or closed and the magazine removed or installed. I doubt you’ll see an internal-locking system on a military or law enforcement duty gun. You most likely will on an M&P that’s civilian owned. When locked, the system prevents firing and requires a key to unlock it. As with the thumb safety, the slide is operational and the magazine can be removed or inserted with the system engaged.

Detailed Disassembly You should read this section all the way through, including the reassembly tips, before taking down the pistol beyond field stripping. Okay? Good. Start with the slide inverted. You’ll probably want to secure the slide between padded vise jaws so you have both hands available. With a small punch, press down on the strikerspring guide (#11). Remove the end cap (#21) upward. Place a finger over the rear of the slide to control the striker assembly when you depress the striker-block plunger (#60).

Withdraw the assembly to the rear. If there’s a reason for further disassembly of the striker, such as part replacement or major filth, a nylon bench block or square of hardwood is suggested. Position the striker against the block to support it. Compress the striker spring (#13). Remove both spring keepers (#12) to free the spring, the guide, the return spring (#15), and the striker (#16). The extractor pin (#3) is drifted toward the top of the slide to access the extractor (#7) and its spring (#8).

The extractor pin on the pistol I used in preparing this article was of a solid configuration. That could possibly change to a roll pin some day. If so, don’t drift it completely out, which will simplify your life when the time comes to reinstall the extractor assembly. Speaking of roll pins, a 1/8-inch roll-pin punch will be required to work on the frame.

After you rotate the takedown lever counter-clockwise until it comes to a stop (so you can lift it away from the frame), pick up that 1/8-inch roll-pin punch and begin moving part #29 right to left’but not completely out. The trigger pin (#30)

When reassembling, the striker guide (A) must be held clear of the end-cap recess (B) for reasons described in the text. is headed at one end. The opposite end is smaller. A drift punch matching the small-end diameter is just the ticket for pushing out the trigger pin right to left. You should be able to lift the locking block (#32), slide stop assembly (#64), and trigger assembly (#35 to 40) out of the frame. No luck? Give #29 another nudge or two, but not all the way out (for reassembly reasons already stated).

Don’t put the 1/8-inch roll-pin punch away. Another pin identical to #29 awaits at the rear of the frame. It’s moved from right to left and gives you freedom to lift off the sear housing (#49). You may have to insert the punch under the housing to start it on its way. The need for this gentle prying depends on how new the pistol is and/or how tight the factory fit between housing and frame was during final assembly.

Once the housing is out of the gun, remove the ejector (#42), set the housing aside, and focus your attention on the magazine catch (#68). Keep this in mind: The magazine-catch spring has no part number. It’s integral with the frame, and it’s not removable. Don’t bend it too much during the following steps or you’ll be in the market for anew frame. With that unpleasant thought held foremost in your mind, move the spring from its recess in the catch, letting it come to rest on the body of the catch.

Slide the catch halfway out, grab the protruding end, and hold onto it while you maneuver the spring around the inside end of the catch. Now slide the catch out of the frame. I know, I know… I haven’t said a word about the detailed disassembly of the trigger or sear housing so far. Don’t send me nasty emails.

I’ve done so deliberately and with every confidence that you’ll be receiving one or both assemblies in a plastic bag thanks to the misguided efforts of an M&P owner to "make the gun better." This often occurs prior to any shooting of the pistol and immediately after it has been taken from its pristine box. When you took the trigger assembly out you noted’or should have noted’how the trigger (#38) and trigger bar (#40) were retained in the assembly by pins #36 and #37.

And when you removed the locking block, you saw (or should have) how the trigger pin (#30) ran through the block and the slide stop. What you may not have noticed was the takedown-lever spring (#34) nesting in its recess on the side of the block and how the trigger-return spring (#35) was assembled with its open end uppermost and its opposite end hooked on the trigger bar.

Of course, your examination of how the open end of the return spring A Word to Our Readers About American Gunsmith’ s Mailing-List Policy Like many other publishers, we make portions of our customer list available to carefully screened companies that offer products and services we believe you may enjoy. Indeed, in all likelihood, we were able to first reach you only because another company graciously permitted us access to its customer list.

If, when we make our list available, you do not want to receive those offers and/or information, plea cting us at American Gunsmith Opt-Out Program, Norwalk, CT 06854-1631. Please be sure to include your current mailing label. B Awas impaled by the trigger pin showed you instantly how the two components were to be reassembled Now for that plastic bag you’ve been handed that contains what once was the sear housing. Insert the searspring (#48) followed by the searreturn plunger (#49) into the housing.

Place the sear (#50) on top of the plunger, and press down to align the sear with its pin hole in the housing. Install the sear pin (#41). Where you go from here depends on whether or not the gun has a magazine safety. If it does have a mag safety, assemble the safety lever (#52) and lever spring (#51) with the bent leg of the spring within the loop on the lever. Install the spring and lever subassembly in the block and secure them in place with the deactivationlever pin (#46). If there’s no such

Smith & Wesson M&P Semi-Automatic Pistol (Specifications subject to change without notice) 1 Front Sight 2 Slide 3 Extractor Pin 4 Firing Pin Plunger Spacer 5 Striker Block Spring 6 Striker Block Plunger 7 Extractor 8 Extractor Spring 9 Rear Sight Set Screw 10 Rear Sight 11 Striker Spring Guide 12 Striker Spring Keeper (2) 13 Striker Spring 14 Striker Bushing 15 Striker Return Spring 16 Striker 17 Barrel 18 Recoil Guide Rod Cap 19 Recoil Spring 20 Recoil Guide Rod 21 Slide End Cap 22 Slide End Cap Plate 23 Magazine Tube 24 Magazine Follower 25 Magazine Spring 26 Buttplate Catch 27 Magazine Buttplate 28 Grip Insert (3 widths) 29 Locking Block Roll Pin 30 Trigger Pin 31 Back Strap 32 Locking Block 33 Takedown Lever 34 Takedown Lever Retaining Wire 35 Trigger Return Spring 36 Trigger Bar Pin 37 Trigger Assembly Pin 38 Lower Trigger 39 Upper Trigger 40 Trigger Bar 41 Sear Pin 42 Ejector (caliber specific) 43 Manual Safety Detent Spring 44 Manual Safety Detent 45 Manual Safety Assembly 46 Sear Deactivating Lever Pin 47 Sear Housing Block 48 Sear Spring 49 Sear Return Plunger 50 Sear 51 Magazine Safety Lever Spring 52 Magazine Safety Lever 53 Sear Deactivation Lever 54 Backstrap (small) 55 Backstrap (large) 56 Spacer Spring 57 Frame Plug, Left* 58 Frame Plug, Right* 59 Magazine Spacer 60 Striker Assembly 61 Slide Assembly 62A Sear Housing w/Manual Safety 62B Sear Housing w/Manual Safety, w/o Sear Deactivator 62C Sear Housing w/Sear Deactivator, w/o Manual Safety 62D Sear Housing w/o Deactivator & Manual Safety 63 Trigger Bar Assembly 64 Slide Stop Assembly 65 End Cap Assembly 66 Recoil Guide Rod Assembly 67 Magazine Assembly (caliber and capacity specific) 68 Magazine Catch Assembly 69 Frame Tool *For pistols without internal-locking systems.

safety present, insert the spring along with the lever that has no loop (#53) into the block, and secure them in the block with the deactivation pin. Reassembly Tips The Sear Housing. Pull the trigger to the rear with the trigger bar out of the frame. Slide the block onto the tail of the trigger bar, insert the housing halfway into the frame, and then install the ejector. Push the housing all the way down and install its retaining pin with the 1/8-inch roll-pin punch.

Opposite page: This schematic shows the M&P pistol with the sear housing (#62A) for a manual safety. The Trigger Assembly. Install the locking block including its takedown-lever wire in the frame. Reinstall the trigger pin left to right. The 1/8-inch roll-pin punch will move the lockingblock pin in the same direction. The Striker Assembly. The vise you used previously to hold the slide will make doing this easier. Push down on the striker-safety plunger and install the striker assembly.

Push the assembly as far into its tunnel as you can, and hold it there with a punch. You won’t be able to press in the end cap unless the striker guide is clear of the cap so it can fully seat in the slide. Then and only then will the end of the striker guide be able to "snap" into its circular cut in the end cap. Beware: This little operation can be somewhat frustrating. The Slide. Insert the M&P’s takedown lever. Rotate it downward. Insert the barrel and guide rod with the guide rod’s small end forward.

Make sure the sear-deactivation lever, if the pistol is so equipped, is in its down position. Align the slide and frame rails/grooves, pull the slide back, and lock it there with the slide-stop lever. Swing the takedown lever upward and control the forward movement of the slide. Safety Checks Push on the upper half of the trigger. It should remain locked. If it moves into the firing position, replace the assembly. Now push on the lower end of the trigger.

When released, the trigger should return to a locked position. If it doesn’t, replace the trigger assembly. The striker safety is supposed to block the striker and prevent any contact with alive round until the trigger is pulled. With the slide off and inverted, push the striker forward. It should not move or protrude from the breechface. If it does, replace it. After that, push and hold the striker-safety plunger down and try pushing the striker forward.

If you don’t succeed, you’ll have to consider replacing more than just the striker.