15 Feb 12
Light-weight revolvers and âbullet-jumpâ
S&W, Ruger, and others are currently making light, five-shot, snubby revolvers, mostly in 38Spl, but there is a trend now toward making these small revolvers to accept autoloading pistol calibers, specifically 9mm.
Sales are brisk!
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
However, these revolvers are so light that, due to their characteristic sharp recoil, âbullet-jumpâ is always a concern.
When the 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 a 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, and thus typically put a heavy crimp into 38Spl and 357Mg 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 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, âNot for Use in Revolvers,â because they calculate bullet-jump will be a problem in some guns.
My advice is:
Stick with 38Spl in snubby revolvers. I donât see a viable solution to 9mm bullet-jump currently. DPX 38Spl 110gr works just fine!
Whatever youâre 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, youâre probably okay.
/John
