By John Farnam
“Bullet-jump” with light-weight revolvers, particularly those chambered for 9mm:
During a Defensive Handgun Course, a student brought a Ruger five-shot revolver, chambered in 9mm.
During an exercise, shooting factory 115gr hardball from a well-known and reputable manufacturer, a bullet jumped forward far enough to protrude from the face of the cylinder and thus prevent the cylinder from rotating normally. In fact, the bullet jumped forward far enough to physically separate from the case. This not only precluded the revolver from continuing to fire, but it also made it impossible to swing out the cylinder, so the revolver could now not be reloaded!
Tilting the revolver upward allowed the errant bullet to fall back far enough so that we could swing out the cylinder. After thus fixing the problem, discarding the entire offending cartridge, and then reloading, the same thing happened a second time a few minutes later!
To be fair, this student fired a number of rounds normally before this started happening, but her faith in her revolver was still irreparably damaged.
Back in February of 2012, I did a Quip on this very issue:
“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 necessarily 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.”
This is the reason revolvers chambered for 9mm, although otherwise well-made and perfectly functional, do not enjoy a place on my “Recommended [Arms] List.” Some ammunition is better than others, but all 9mm rounds share this same issue, even expensive high-performance brands. The 9×19 cartridge was designed to function in autoloading pistols, not revolvers!
I’m still a fan of snubby revolvers and own several, but my recommendation, when you share my enthusiasm for them, is to stick with 38Spl. The bullet-jump issue still exists, to be sure, but to a much lesser degree, particularly when you’re shooting high-performance ammunition, like Cor-Bon’s 110 gr DPX or Speer Gold-Dot. Manufacturers ensure that these bullets are adequately crimped-in and are thus unlikely to migrate.
/John
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Remington UMC FMJ 130gr .38 Special Ammunition, 250rds - 23731 | Palmetto State Armory | $ 158.99 $ 144.99 |
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Bigg,
The reason this isn’t a problem in pistols, as opposed to revolvers, is that the rounds in a pistol aren’t being held captive by their rim, but are instead in a magazine that allows them to move (albeit very little) as a unit; there are no forces acting on the bullet to pull them out of the case. In fact, any recoil forces act to push the bullet further into the case as the round tries to remain still as the magazine recoils with the pistol.
Good analysis of the problem and explanation! Thank You,!
Mike was right regards the Lee crimp die. It really lets you make your ammo to high end specs. I guess the old wheel guns retro fitted to 45acp didn’t generate enough recoil impulse to be a problem for the troops of WW2.
I’ve been shooting an S&W M1917 for about 60 years now and have never experienced bullet migration with it. It’s heavy for a pistol, but is still one of my favorite handguns. If you ever get a chance to shoot one, be prepared for a unique and pleasurable experience in handgun shooting; almost no muzzle flip. Instead, the whole thing rises up, and allows quick target acquisition. Terrible double-action trigger pull. Some of my students don’t have enough strength in their fingers, but single-action is nice.
I have two fine 9mm revolvers, both Smith & Wessons. One is a seven shot and one an eight. The same bullet migration situation existed.
The solution was very simple. Buy a Lee crimp die and heavy crimp all rounds before snapping them into their full moon clips.
Situation resolved.
Your student should be using moon clips to prevent the bullets from jumping forward specifically during firing. The moon clip providing the necessary headspace. Since the 9mm cartridge does not have a cartridge case rim, the cylinder fails to secure the round specially if it gets hot.
What Is a Moon Clip?
Moon clips are devices for holding cartridges as they are loaded, fired and unloaded in a revolver. As mentioned above, the clips allow proper headspace and ejection with cartridges not originally intended for the revolver.
Good to see a useful article from John for a change! I have always wanted a 9mm revolver, either with moon clips or with an ingenious solution that eliminates the need for moon clips as one manufacturer, I believe Ruger or Charter Arms, had many years ago. Reading this article has changed my mind. Absent a pressure chart in front of me, I believe 9mm rivals or exceeds .38 Spl +P+ ammo in chamber pressure. I always thought it would be an ideal cartridge for a snubby revolver due to its shorter cartridge OAL. I always figured a properly motivated… Read more »
I have been shooting revolvers for nearly 60 years and have never had such a problem. Those revolver are 22, 22 magnum, 38s both Smith and Wesson and Colt, 357 magnums, 41 magnums and all time favorite 44 magum. All of these were barrel lengths from 3 in 6 inch. Never a problem of any kind.
I;m pleased with my never let me down revolvers unlike the frequent jamming autos.
That’s great. But I just had it happen with my S&W 586 .357 with a six inch barrel.
I did manage to get the cylinder open and remove the offending round, but having never heard of this, I didn’t realize this was a “thing” until just now.
That’s what I get for buying an “off” brand (for the savings).
Runs fine in my lever action, of course, and that’s where I’ll use it up.
Do you realize your comment is to a post from 7 years ago. Myself and others have done the same thing.
🙂
Hi Music Man! I know, now. I have responded to these older articles and comments in the past without realizing just how old they really were. At some point, later on, I glanced at the age of the comments. This article may have originally come out before I was aware of AmmoLand’s existence. Despite its age, I find it useful. Yes, I respond to the comments too, just in case the poster is still around and viewing.
I have a Smith & Wesson 610 that does the same thing. But since I cast boolits and roll my own, I can work around it with lighter loads or even tighter taper crimping. But it bothers me that such a nice revolver works best when it’s NOT used to its fullest potential. I’m guessing the taper crimped rounds in the pistol grip of a semi auto just don’t feel the “inertial impulse” the same rounds feel higher up and farther forward in the cylinder of a revolver. Much shorter moment arm in the magazine than in the cylinder sort… Read more »
The main reason for this happening is that Semi-auto pistols and pcc rifles (9mm, 380, 45acp, etc.) headspace off the case mouth, requiring a taper crimp, and cannot use a good roll crimp. Whereas, rimmed cartridge cases, (38spl, 357mag, 44mag, etc.) headspace off the rim, and can be roll crimped to eliminate “bullet jump”. High powered rifle cartridges should also be roll crimped most of the time, unless being shot in a single shot rifle or a bench rest match rifle. This keeps the projectile from getting pushed farther into the case neck, possibly creating an overpressure situation. Some match… Read more »
I call it bullet jump! I have 2 Charter Arms, 3” .44 Bull Dogs. One is solid SS & the other is blue steel & alloy, with a tapered barrel. The SS gun weighs 2 oz. More than the blue one. 22.78 vs 20.49.
Shooting CCI shot loads, with aluminum cases, the shot capsules jump the crimp & block cylinder rotation in the blue gun but not in the SS gun! This is the only loading that has ever done this, in the 25 plus yearsI have had these guns!
Comments are 7 years old.
Revolvers in general would not make my Recommended Arms List. There’s nothing inherently wrong with them, but situations in which they offer a definitive advantage over a semi-automatic pistol are few. Specifically, a revolver is better if you end up jabbing the target with the barrel before shooting or plan to leave it in a drawer for years at a time. At the same time, compared to a 5-shot DAO revolver a 6+ shot single-stack striker-fired pistol will be thinner (and generally smaller overall), have less felt recoil, be simpler and faster to reload for anyone not named Miculek, and… Read more »
I have many experiences to the contrary, and several issues with your summation. The spray & pray method of semi-auto`s is no contest to calm revolver fire, which can be fired just as fast,if not faster. You mention a top pistolero. See also, Ed McGivern.
@David T, I have his book “Fast and Fancy Revolver Shooting”!
@Adam, While I do not disagree, you forgot the most important advantage of all: revolvers do not leave all that embarrassing evidence behind. I am thinking that that Ruger GP 100 .22lr ten shot revolver combined with CCI quiet .22 ammunition might create some interesting possibilities.
The fact that revolvers can be fired as fast by someone at or near the pinnacle of shooting skill means little to the 90%+ of us who are not at that level. Additionally, I can see how a revolver “shooter” who leaves theirs in a drawer for years at a time rather than practicing with any regularity would be unable to competently handle a semi-auto pistol, and instead resort to “spray and pray”.
The venerable revolver in 22 cal. , is my choice. My ‘pinnacle’ of skill was decades ago. However, I can still deploy and fire in a timely fashion. Hit what I want, where I want. The scattered fired cases with prints on them, from the semi auto, give law enforcement a place for those cute little yellow flags. Note; I do carry a semi auto, of Walther manf.. But , when ‘afield’, I carry 3 revolvers & 2 semi`s, 5 knives. Calibers from 22, 38,45 acp,380.. Then there is ‘baby’. Whom I am quite fond of. Baby is a Rem.870,… Read more »