Description
The Smith & Wesson M&P340 is a five-shot J-frame built for people who want serious firepower in the smallest package possible. It's a modern take on the classic Centennial AirLite design, chambered in .357 Magnum and also happy running .38 Special and .38 +P. The big story here is the scandium alloy frame mated to a PVD-finished stainless steel cylinder. That combination keeps the gun down around 13.3 ounces empty while still being tough enough to handle full-power magnum loads, something an aluminum frame simply can't do for long.
What Sets the M&P340 Apart From a Standard J-Frame
Two features really define this one. First is the enclosed, snag-free hammer, which means there's nothing to catch on a pocket lining or shirt hem when you draw. It's double-action only, so the trigger pull is the same every time. Second is the XS Sights 24/7 tritium night front sight paired with an integral U-notch rear. That glowing front dot is a genuine upgrade over the plain ramp sights most snubbies ship with, and it makes a real difference picking up the gun fast in low light. This particular model also comes without the internal lock, which is a popular choice among folks who prefer the cleaner, simpler frame.
Living With the M&P340 in the Real World
Let's be straight about recoil. A 13-ounce .357 Magnum is going to let you know it went off, and full-house 158-grain loads are stout. Most people who carry one shoot .38 +P or lighter 125-grain magnum loads for practice and defense, which keeps things controllable and follow-up shots fast. The beauty is that you carry it constantly and barely notice it's there, whether it's a pocket holster, an ankle rig, or a jacket pocket on a morning walk.
This is a carry gun first and foremost, ideal as a primary concealed piece, a backup, or an off-duty option. If you want maximum power in a revolver you'll actually have on you every day, the M&P340 earns its keep.
Key Specifications
- Manufacturer: Smith & Wesson
- Model: M&P340
- Manufacturer Part Number: 103072
- UPC: 022188030723
- Caliber: .357 Magnum / .38 Special +P
- Action: Double Action Only
- Capacity: 5 Rounds
- Barrel Length: 1.875"
- Overall Length: 6.31"
- Weight: 13.3 oz (empty)
- Frame Material: Scandium Alloy
- Cylinder: PVD-Finished Stainless Steel
- Finish: Matte Black
- Front Sight: XS Sights 24/7 Tritium Night Sight
- Rear Sight: Integral U-Notch
- Safety: No Internal Lock
- Hammer: Enclosed / Snag-Free
- Grips: Black Synthetic
Frequently Asked Questions
Can the M&P340 shoot .38 Special as well as .357 Magnum?
Yes. The M&P340 is chambered in .357 Magnum, which means it will also safely fire .38 Special and .38 Special +P loads. Many owners practice with .38 ammo since it's softer shooting and cheaper, then carry it loaded with a defensive magnum or +P round. Because it has a steel cylinder rather than titanium, it isn't restricted to heavier bullet weights the way the 340PD is.
Is the recoil really that bad?
Full-power 158-grain .357 Magnum loads are genuinely stout out of a 13-ounce gun, and most people don't enjoy long range sessions with them. The smart move is practicing with .38 +P or lighter 125-grain magnum loads, which keep recoil manageable and follow-up shots quick. A set of cushioned aftermarket grips like a Hogue Tamer can also tame things considerably for those who find it punishing.
What does "no internal lock" mean on this model?
Some S&W revolvers include a small key-operated lock above the cylinder release that can disable the gun. This version omits that feature entirely, leaving a cleaner frame. It's a popular preference among folks who like the simpler look and want one less mechanical part in the design.
Why is the hammer enclosed instead of exposed?
The enclosed, snag-free hammer is one of the defining traits of the Centennial-style J-frame. With no hammer spur sticking out, there's nothing to catch on clothing, a pocket lining, or a holster when you draw. The tradeoff is that it's double-action only, so you can't cock it for a single-action shot, but for a defensive carry gun that's exactly what most people want.
Is the M&P340 a good gun for a first-time shooter?
It's a fantastic carry gun but not the easiest starter revolver. The lightweight frame, snappy recoil with magnum loads, and a double-action trigger pull around 12 pounds all demand practice to shoot well. New shooters are often better served learning on a heavier steel-frame revolver first, then graduating to a lightweight scandium gun like this one once their fundamentals are solid.
What sights does it come with?
It ships with an XS Sights 24/7 tritium night front sight paired with an integral U-notch rear. The glowing tritium front dot makes the gun much faster to aim in low light than a plain black ramp, which is a meaningful upgrade on a defensive snub-nose. It's one of the features that helps justify the M&P340's price over a basic Airweight.





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