chrisintexas
New member
Describe bullet setback and how to prevent it. Also what calibers are inherently prone to bullet setback. Thanks so much.
Bullet setback and calibers inherently prone to it
- Thread starter chrisintexas
- Start date
If you reload then follow the recommended crimping procedures for the caliber and load to the recommended length.
If you buy factory ammunition, don't rechamber it a significant number of times.
Keep in mind that while there's some expectation that a premium self-defense round might be chambered more than once, there isn't the same expectation for inexpensive practice ammo. I've never rechambered a round of premium self-defense ammo enough to detect setback, but I've seen some inexpensive practice ammo that will setback noticeably from only one chambering and enough to be scary from being chambered only twice.
The rechambering issue is autopistol specific as rechambering a round in a revolver has no effect on setback. However, revolvers can have a similar problem but in reverse where the bullet is literally pulled forward out of the case by recoil. In extreme cases this can tie up the revolver.
So in autopistols rechambering of rounds should be kept to a minimum. In revolvers, rounds should not be kept in the cylinder for an excessive number of firings. In other words, don't load the cylinder fully, fire a shot, replace that cartridge, fire it again, replace it, fire it again, etc. while the other rounds remain in the cylinder unfired.
It's less important which calibers/loadings are prone to setback, more important which calibers/loadings will have a big pressure increase as a result of it, and most important to just avoid doing the things that cause setback in the first place.
If you buy factory ammunition, don't rechamber it a significant number of times.
Keep in mind that while there's some expectation that a premium self-defense round might be chambered more than once, there isn't the same expectation for inexpensive practice ammo. I've never rechambered a round of premium self-defense ammo enough to detect setback, but I've seen some inexpensive practice ammo that will setback noticeably from only one chambering and enough to be scary from being chambered only twice.
The rechambering issue is autopistol specific as rechambering a round in a revolver has no effect on setback. However, revolvers can have a similar problem but in reverse where the bullet is literally pulled forward out of the case by recoil. In extreme cases this can tie up the revolver.
So in autopistols rechambering of rounds should be kept to a minimum. In revolvers, rounds should not be kept in the cylinder for an excessive number of firings. In other words, don't load the cylinder fully, fire a shot, replace that cartridge, fire it again, replace it, fire it again, etc. while the other rounds remain in the cylinder unfired.
It's less important which calibers/loadings are prone to setback, more important which calibers/loadings will have a big pressure increase as a result of it, and most important to just avoid doing the things that cause setback in the first place.
Aguila Blanca
Staff
^^^
John KSa has summed it up fairly well. One thought I would add is that the issue may be more likely to crop up in some pistol designs than in others. I shoot mostly 1911s in .45 Auto, and it is a known issue in the 1911 with standard (not ramped) barrels. The round typically hits the feed ramp in the frame fairly low at a comparatively sharp angle, then glances off/up toward the chamber mouth. Setback occurs with all ammo types -- I have noticed it even with premium, "name brand" JHP self defense ammunition.
Other guns (did I really just write that?) may have less of an issue ddue to a straighter feed path.
John KSa has summed it up fairly well. One thought I would add is that the issue may be more likely to crop up in some pistol designs than in others. I shoot mostly 1911s in .45 Auto, and it is a known issue in the 1911 with standard (not ramped) barrels. The round typically hits the feed ramp in the frame fairly low at a comparatively sharp angle, then glances off/up toward the chamber mouth. Setback occurs with all ammo types -- I have noticed it even with premium, "name brand" JHP self defense ammunition.
Other guns (did I really just write that?) may have less of an issue ddue to a straighter feed path.
Bullet setback is the bullet being pushed into the case. Usually caused by insufficient crimp. There are no cartridges that are "prone" to it, but any cartridge used in a lever action of those loaded to excessive velocity can have it happen.
If repeated chambering causes it, the ammo wasn't crimped correctly in the first place.
If repeated chambering causes it, the ammo wasn't crimped correctly in the first place.
Bullet setback is the term used to describe a bullet being pushed deeper into the case due to forces exerted on it during the feeding cycle.
The way you prevent it is to make your ammunition PROPERLY. Almost no one does this, today.
There are NO calibers that are "prone" to setback. Setback, if it occurs, is due to forces on the bullet during the feeding cycle. The force is exerted on the bullet by the GUN, and its design features. And it varies.
One gun design may "work harder" at setback than another. Some designs avoid the issue entirely. Others actually compound it.
A single shot never suffers from this problem, nor do revolvers. Semis, and tube magazine guns put the greatest "push" on the bullet.
people today accept setback as a common thing, and tell you not to rechamber ammo too much...and they aren't wrong. Ammo makers don't make the most durable ammo possible, (or don't seem to these days), they make it good enough for "normal" use.
I have personal experience with some ammo that showed me setback was not an inevitable thing. Federal 185gr JHP .45ACP, the owner bought 2 boxes in 1980. Gun was a SigSauer P220. He kept one magazine full, as his "defense ammo) for over 20 years!!! The rounds had been chambered hundreds of times (At least). They had been cycled enough that the nickel cases had brass stripes all over them.
The bullets NEVER MOVED. Not any, ever. I measured them, several times over several years. Those rounds were made PROPERLY!!!
He did, finally shoot them up, in the early 2000s, all fed and functioned flawlessly. Setback does not HAVE to happen.
It does happen, and often, because a lot of ammo is made to be good enough, not the best possible.
J.G. Terry
New member
Set Back?
When this hot button topic comes up it may be good to look at the handgun not the cartridges. One plastic pistol from Austria has a rep for this set back in 357 SIG. It is educational to take the slide off the handgun and insert a loaded magazine. You can put the barrel on the locking block. Seeing the relationship may give you an idea about the problem with "set back," You will notice the long hard journey this cartridge has from the magazine up the fed ramp and into the chamber.
When this hot button topic comes up it may be good to look at the handgun not the cartridges. One plastic pistol from Austria has a rep for this set back in 357 SIG. It is educational to take the slide off the handgun and insert a loaded magazine. You can put the barrel on the locking block. Seeing the relationship may give you an idea about the problem with "set back," You will notice the long hard journey this cartridge has from the magazine up the fed ramp and into the chamber.
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