S&W Bodyguard Upgrades

I have to admit that I like the M&P series of Smith & Wesson guns They are inexpensive, well designed, and have become quite popular. Most of them are striker fired but not the little S&W M&P Bodyguard 380. This ultra-compact gun is double-action only and utilizes a small hammer. Its .380 ACP cartridge has enough power for effective self defense. The built-in laser is an additional nice option. But the most attractive feature is its small size and weight.

Many people carry it now without the unpleasant feeling that the gun is pulling their pants down. While an all-around nice gun, however, it is not without certain weaknesses. First, the trigger has a overly-long pre-travel, after-travel, and reset. Second, the thumb safety cannot be moved with the thumb of the holding hand. It requires the other hand to assist and even then it’s not as easy as it could be. Third, the gun has a tendency to produce a weak primer strikes. Finally, the trigger is heavy.

I have a reason for putting these issues in this order. While the list could be continued, I’ve noted the major ones. Please remember that this gun became popular because its pluses greatly outweigh any minuses. Even better, most of these little flaws can be improved or eliminated. Lets look at them one-by-one. Trigger pull Pre-travel, after-travel, and reset can be improved by about 30% with the installation of the Santiago Short Stroke Trigger Kit for Bodyguard, manufactured by Galloway Precision Products Inc.

Fletcher, NC 28732, GallowayPrecision.com). I need to point out, though, that replacement of the stock trigger with this recommended kit does not reduce the trigger pull, it just makes it shorter. Thumb Safety The factory thumb safety is a shallow, stamped steel part and does not have enough gripping roughness. Several years ago one of my customers brought this gun to the shop and asked me to do something to make the safety more friendly. His safety was especially hard.

After dealing with 1911 pistols for along time, the very natural solution was to create an analog of the extended thumb safety. I made a small attachment to the standard safety and shaped it as a small lever. This little extension is a brazedon silver-brass compound and then spot blued.

There are a couple of things to take in account. First, the safety is made of hardened, high-carbon, stamped steel. It also is stainless. Therefore, the extension should also be high carbon. To maintain the original hardness of the safety lever with this extension, it should be heat treated during brazing (the temperature of brazing is just right) and then tempered to a regular spring hardness of about HRC 40- 45. After shaping and polishing the extension, apply spot bluing to the stainless parts.

I use Caswell Stain- I have received multiple requests for this safety and many people shipped me their guns for this update. I need to point out that modifications are done on the standard safeties installed on the gun since S&W does not sell safeties as apart. Weak Strike As usual, a weak strike ends up with occasional misfires.

Since this gun is double action only, the trigger pull This part is shallow, stamped steel and does not have enough gripping roughness. less Steel Blackener (855/CAS- WELL, Caswell- Plating.com.) The resulting safety is shown here. After publishing this modification on my Rustblue Gunsmithing website (RustBluing.com, works against the mainspring. One of the ways of increasing the hammer punch is to use a more powerful spring. The Santiago trigger kit includes an extra-power mainspring for this reason.

Of course, an extrapower spring increases the trigger pull where a weaker spring reduces it but lightens the hammer strike as well. The hammer strike and trigger pull on this gun are interdependent. My major effort was to make the hammer strike more efficient without adding weight to a trigger pull. It can be done. We need to recall some simple mechanics. The whole purpose of the mainspring and hammer is to provide sufficient acceleration to the firing pin.

In other words, change the velocity of the firing pin from rest to fast enough such that the amount of firing pin motion is sufficient for igniting the primer. Here, mis the mass of the firing pin, and V1 is its final velocity when striking the primer, Fis the force applied by the hammer to the firing pin, and tis time. Newton’s second law gives usa relation of F*t=m*V1, where tis a duration of the force (F) applied to the firing pin. In other words, during the interval of time the hammer accelerates the firing

The firing pin tail, subjected to the hammer blow, is very short. Normally, about 1mm. The firing pin with recess cut in front is relieved about 2.5mm from this slot. The Sslot is for the firing pin block. pin. This is equivalent to V1=t*F/ m. Since F/mis practically constant in our process, the only physical amount that affects velocity is time. By increasing t, we increase V1 and our primer striking efficiency. Let’s look at t closer.

This is the time duration between the first touch of the hammer and firing pin and the stop of the hammer by the body of the slide. If we can modify the firing pin so that its tail sticks further back without making the firing pin longer, we increase the duration (t) of the hammer exerting force ( F) upon the firing pin. The formula shows that if this duration is x times longer, then the velocity Now it extends to about 3.5mm. of the firing pin striking primer is x times greater.

In order to increase the extension of the firing pin back, we need to modify it. The firing pin is under pressure from the return spring and its movement back is restricted by the cross pin. The firing pin has a recess which has to be cut in front to relieve about 2.5mm of this slot. In the photo, Smarks this slot for the firing pin block. Its major purpose it to prevent motion of the firing pin going forward if the trigger is not pulled or the slide is not in battery.

I did not have to modify this slot but it could potentially restrict the motion of the firing pin from going back and needs some attention. After modification, the firing pin extends back about 3.5mm. According to formula above, this insures the velocity (V1) of the firing pin at the moment of striking the primer is 2.5 times greater than that of the original strike.

In all my cases, this modification was more than enough for providing sufficient strike of the primer, eliminating all misfires related to a weak strike. One note on firing pin modification. This firing pin is of the inertial type, meaning it does not protrude through the face of bolt when the hammer is all the way down. The protrusion and a primer strike happens when the firing pin is moving forward with velocity provided by the hammer; by inertia.

I mention that for those folks that might be tempted to increase the length of the firing pin in an attempt to solve the weak strike problem. This is not anew idea but in this case it can prevent reliable cycling. Reducing Trigger Pull Now that we can significantly increase the firing pin energy without increasing the power of the mainspring, we can consider reducing the power of the spring if a lighter trigger pull is desired. Normally, I use a reduced power 1911 spring for this purpose.

Some adjustments of the length are needed. This step requires proper testing. With a properly shortened and reduced power spring, the amount of the trigger pull can be dropped down to about three pounds. These fixes can improve an already-good pistol. See if they work as well for you as they have for my customers. AG