Pushing the Envelope vs. Pushing Your Luck

Pictured below are the sad remains of a S&W M&P 340 revolver.  The 340 is a J-Frame chambered in .357 Magnum.  Its frame is an aluminum alloy infused with a small percentage of Scandium, and it weighs in at 12 ounces.

The owner fired six rounds of .38 Special through it without issue. The first shot of .357 blew up the gun. The owner was unharmed, as all of the unpleasantness happened forward of the muzzle.

This isn’t a takedown gun, and those pieces aren’t supposed to be separate.  The loads were very mild 125gr .357’s.  Ammunition was not the issue.

The ejector rod had bent, and the cylinder was stuck shut.  Immediately noticeable was this little problem:

The barrel shroud had separated from the frame and was spinning freely.  The barrel had torqued itself forward about 3/8″ and since it was already DOA, I went ahead and unscrewed it.

The barrel itself is very light and made of thin steel.  It screws directly into the frame, right where the crack appears. This highlights a serious design flaw of this weapon. The area where the yoke meets the frame is far too thin and brittle. Furthermore, the threads in the barrel mate to aluminum threads rather than steel.

A possible fix would be to pin a steel bushing to the frame, into which the barrel can then be screwed. Even then, I’m still not sure that an aluminum frame, no matter how well heat-treated, can hold up to the pressures involved.

This is the second failure of this material I’ve seen, and there are several other documented cases. It may be that the engineers at Smith & Wesson have reached beyond their grasp with this design. The manual warns against using any loads lighter than 125gr, and I’ve heard of lighter loads “jumping” the crimp and lodging against the forcing cone under recoil.

The final concern is recoil. To shoot Magnums in a gun this small and light is to know pain. I’m not exaggerating in the least. .38 Special has an appreciable snap out of the gun, but Magnums not only torque the wrist sharply, they cause the gun to tear into the palm and webbing of the hand. It’s not uncommon for these guns to draw blood from the shooter.

File this gun under “things that seemed like a good idea at the time,” but I can’t recommend it to anyone who plans on shooting it with any regularity.  While I’ve no doubt that Smith & Wesson will make things right, the owner will likely be settling on a more practical sidearm.