Lightweight Revolvers and the Dangers of “Bullet-Jump”

The following email blast from John Farnham is republished here with the gun guru’s blessing. Click here to visit his website Defense Training International, Inc.

“S&W, Ruger, and others are make a wide range of light, five-shot, snubby revolvers, mostly in .38 special. These light-weight revolvers make wonderful back-up pistols. I carry a S&W 340PD regularly, and I hardly know I have it on! Many other gun-carriers similarly rely on them. There’s a new trend towards making these small revolvers accept autoloading pistol calibers, specifically 9mm (e.g., the Taurus 905 revolver above). Sales are brisk! However, due to their characteristic sharp recoil, “bullet-jump” is a concern. This is especially true for pistol caliber wheelguns . . .

When a revolver fires, remaining cartridges in the cylinder (yet to be fired) are subjected to significant G-forces as the pistol recoils. Sometimes, it is enough to persuade an yet-unfired bullet to migrate forward far enough to protrude from the front of the cylinder, preventing the cylinder from rotating normally, and thus preventing the revolver from firing.

Ammunition manufacturers have been familiar with this issue for a long time. They typically put a heavy crimp into .38 special and .357 magnum cartridges as part of the manufacturing process. That crimp usually suffices to mitigate the bullet-jump issue, even in small revolvers.

However, with the advent of small, light revolvers chambered for 9mm, the problem is, once again, rearing its ugly head as a major issue, as most 9mm ammunition does not come with any kind of bullet-holding crimp.

In fact, on many boxes of currently-produced, high-performance 9mm ammunition, manufacturers have printed the warning, “Not for Use in Revolvers,” because they calculate bullet-jump will be a problem in some guns.

My advice: stick with .38 special in snubby revolvers. I don’t see a viable solution  to 9mm bullet-jump currently. DPX .38 special 110gr works just fine.

Whatever you’re using, test it! Load your revolver and fire three  shots, one-handed. Then, open the cylinder and check the remaining two rounds for signs of bullet-jump. Repeat the routine several times. When all unfired cartridges look normal, you’re probably okay.”

/John