The Dangers Of Bullet Setback

[billt460]

This is something few shooters think about, and even fewer worry about. But it's a good idea to be at least cognisant of it, because it can happen with factory ammunition, as well as handloads. In semi auto pistols it can becaused by 2 basic factors, recoil, and the slide pushing the nose of the bullet into the feed ramp.

This is the exact opposite of what happens in revolvers, where that same recoil can pull the bullet slightly out of its case as it rotates in the cylinder. In revolvers, (especially in the Magnum cartridges), it can be enough to pull the bullet far enough out of its case to tie up the gun.

This doesn't happen much because revolver cartridges usually have a heavy crimp on them to prevent this. And most revolver cartridges headspace on the rim. But semi auto pistol rounds cannot have heavy roll crimps, because they headspace on the mouth of the cartridge. So a taper crimp must be used. And that type of crimp doesn't provide the "grip" a heavy roll crimp does.

A few thousandths of setback isn't going to hurt anything, but the article below states that a setback of just .010 or more can become a problem waiting to happen. And .035 + has the potential to cause a disaster.

I'm not trying to create fear. But it is something most shooters should at least be aware of. And it's quite easy to check for, by simply eyeballing your ammo before you shoot it.

https://www.recoilweb.com/bullet-setback-fears-160844.html

 

[MasterSolenoid]

Good thoughts.
Maybe make yourself a Go/NoGo gage.

 

[billt460]

The problem with a Go / No Go gauge is the setback round, (No Go), will still easily chamber, because the case headspaces on the mouth of the case itself. Chambering is not affected by a shorter cartridge overall length.

 

[burbguy82]

Great post, and an excellent topic.

But semi auto pistol rounds cannot have heavy roll crimps, because they headspace on the mouth of the cartridge.

Yes this is true, but semiauto pistols and pistol caliber dont really use "headspace" like a rifle does, being as they are delayed blowback operated with no locking function. The real critical zone is the the chamber cut.

This of course is much more important with revolvers, but the jump is far greater in a revolver than any other, and yet revolvers are super accurate........................an thing that has perplexed me forever.

A few thousandths of setback isn't going to hurt anything, but the article below states that a setback of just .010 or more can become a problem waiting to happen. And .035 + has the potential to cause a disaster.

I am not so sure of this, are you referring to revolver or semi auto? In my experience with pistol, if you can close the gun and the round if proper pressure=no problem, if you cant close the gun=problem.

 

[spasm3]

Thanks for posting this. I generally don't put one in the pipe from the magazine. I load the magazine, chamber a round by hand , then insert/seat the magazine.
But I could see this problem if you load /unload your carry ammo, chambering the same round from the mag over and over.

 

[billt460]

Great post, and an excellent topic.


Yes this is true, but semiauto pistols and pistol caliber dont really use "headspace" like a rifle does, being as they are delayed blowback operated with no locking function. The real critical zone is the the chamber cut.

This of course is much more important with revolvers, but the jump is far greater in a revolver than any other, and yet revolvers are super accurate........................an thing that has perplexed me forever.

I am not so sure of this, are you referring to revolver or semi auto? In my experience with pistol, if you can close the gun and the round if proper pressure=no problem, if you cant close the gun=problem.

Semi auto. A round that is setback enough to cause an issue will still chamber easily in a semi auto chamber. (.380 / 9 MM / .40 S&W, .45 ACP). If the bullet were seated to a longer O.A.L. then it might not chamber because depending on how the barrel itself is rifled, the nose of the bullet could possibly engage the rifling, before the case mouth contacts the edge of the chamber it would normally headspace against.

This could cause the slide to not go into battery. It would all depend on how much freebore the barrel in question has built into it.

 

[Astro14]

Thanks for posting this. I generally don't put one in the pipe from the magazine. I load the magazine, chamber a round by hand , then insert/seat the magazine.
But I could see this problem if you load /unload your carry ammo, chambering the same round from the mag over and over.

!!!!

What do you mean “chamber a round by hand”?

For nearly every semi-auto I own, this is a huge mistake. The round is designed to be fed FROM THE MAGAZINE so that it slides up the breech face and under the extractor during feeding.

Loading a round by hand forces the extractor to “jump” over the cartridge rim, leading to feed problems, broken extractors (particularly in 1911s) and other malfunctions. It is worse than “riding the slide” to load a semi-auto.

Insert magazine - send slide forward by the recoil spring, either by racking it (slingshot) or releasing a slide that was locked back.
Don’t ride it.

Then remove and top off your magazine, if you want/need the extra round.

Don’t drop a round in the chamber and send the slide forward - because you’re making the extractor do something it wasn’t designed to do.

 

[burbguy82]

Semi auto. A round that is setback enough to cause an issue will still chamber easily in a semi auto chamber. (.380 / 9 MM / .40 S&W, .45 ACP). If the bullet were seated to a longer O.A.L. then it might not chamber because depending on how the barrel itself is rifled, the nose of the bullet could possibly engage the rifling, before the case mouth contacts the edge of the chamber it would normally headspace against.

This could cause the slide to not go into battery. It would all depend on how much freebore the barrel in question has built into it.

Ok, so you are talking a longer OAL than proper not shorter. Yes I agree 100%.

This was one design feature with the legendary Israeli Desert Eagle, and it rotating bolt design. Originally chambered in 44Mag, (At the time the most powerful handgun round), due to its ability to use a "revolver" round in a semi auto.

 

[AZjeff]

Excellent heads up A14. Will add that not all brands consider the slide lock to be a slide release. Out of habit I pull the slide full back and release and let the pistol load as Mr. Browning or Mr. Glock etc intended. Semi autos aren’t meant to be loaded gently.

 

[burbguy82]

!!!!

What do you mean “chamber a round by hand”?

For nearly every semi-auto I own, this is a huge mistake. The round is designed to be fed FROM THE MAGAZINE so that it slides up the breech face and under the extractor during feeding.

Loading a round by hand forces the extractor to “jump” over the cartridge rim, leading to feed problems, broken extractors (particularly in 1911s) and other malfunctions. It is worse than “riding the slide” to load a semi-auto.

Insert magazine - send slide forward by the recoil spring, either by racking it (slingshot) or releasing a slide that was locked back.
Don’t ride it.

Then remove and top off your magazine, if you want/need the extra round.

Don’t drop a round in the chamber and send the slide forward - because you’re making the extractor do something it wasn’t designed to do.

This is the "controlled feed system". Mostly attributed to the Mauser type extractor, which has no rebound spring. And although a good practice, with some modern designs, I have found it to be a non issue, at least with handguns with a coil spring and plunger. The XD pistol for instance, closely mimics the Mauser, and has no spring, Glock pistols, USP and so on have the spring and plunger system.

Doing different drills, I have chambered a round in my XD thousands of times, in the manner in question, and has had no effect of performance, none whatsoever, with 13k or so down the pipe. Of course most of these are through the mag, but probably 1000 from a loaded chamber.

I agree it is not a good practice, but have found it to be largely untrue. Modern firearms are very durable.

*edit: I hit touched enter by mistake before ending the reply..........

 

[ammolab]

Great post, and an excellent topic.


Yes this is true, but semiauto pistols and pistol caliber dont really use "headspace" like a rifle does, being as they are delayed blowback operated with no locking function. The real critical zone is the the chamber cut.

This of course is much more important with revolvers, but the jump is far greater in a revolver than any other, and yet revolvers are super accurate........................an thing that has perplexed me forever.

I am not so sure of this, are you referring to revolver or semi auto? In my experience with pistol, if you can close the gun and the round if proper pressure=no problem, if you cant close the gun=problem.

Wow! At least click on the link and look at the picture and see what “SETBACK” is all about. It is raised chamber PRESSURE from a deeply seated bullet during feeding. Absolutely nothing to do with functional problems or headspace.

Also most auto pistols 9mm and larger do not function strictly by blowback but are locked breech recoil operated.

 

[Astro14]

This is the "controlled feed system". Mostly attributed to the Mauser type extractor, which has no rebound spring. And although a good practice, with some modern designs, I have found it to be a non issue, at least with handguns with a coil spring and plunger. The XD pistol for instance, closely mimics the Mauser, and has no spring, Glock pistols, USP and so on have the spring and plunger system.

Doing different drills, I have chambered a round in my XD thousands of times, in the manner in question, and has had no effect of performance, none whatsoever, with 13k or so down the pipe. Of course most of these are through the mag, but probably 1000 from a loaded chamber.

I agree it is not a good practice, but have found it to be largely untrue. Modern firearms are very durable.

*edit: I hit touched enter by mistake before ending the reply..........

It matters enough that some gun manufacturers, including Springfield, warn against it.

This is an excerpt from a Springfield Armory 1911 manual.

So, clearly a warning against it in a 1911, because it can break the extractor (leaving you with a paperweight that will not fire another round)n and while Glock, etc. extractors with a spring and plunger may be more resistant to damage from this practice, making the extractor jump over the rim is not best practice.

If you don’t have the advantage of a thousand rounds of testing, as you do, then use of this method is unwise - you’re loading the gun in a way which wasn’t intended, and can induce malfunctions, like a failure to go completely into battery, damage to parts, damage to the cartridge.

It’s your gun - but for everyone else, you should load it the way it was intended - from the magazine.

Edit - Here is the Springfield XD manual - note the highlighted section. Same warning, in bold, stating “never load cartridge by hand directly into the chamber”

Just don’t do it.

 

[spasm3]

!!!!

What do you mean “chamber a round by hand”?

For nearly every semi-auto I own, this is a huge mistake. The round is designed to be fed FROM THE MAGAZINE so that it slides up the breech face and under the extractor during feeding.

Loading a round by hand forces the extractor to “jump” over the cartridge rim, leading to feed problems, broken extractors (particularly in 1911s) and other malfunctions. It is worse than “riding the slide” to load a semi-auto.

Insert magazine - send slide forward by the recoil spring, either by racking it (slingshot) or releasing a slide that was locked back.
Don’t ride it.

Then remove and top off your magazine, if you want/need the extra round.

Don’t drop a round in the chamber and send the slide forward - because you’re making the extractor do something it wasn’t designed to do.

Interesting, I didn't know that. I have always done this. But I see what you mean. I don't own a 1911(yet). I don't remember any of my Ruger or my Springfield rdp mentioning not to do this, but I will read up further.

 

[oil pan 4]

This is something few shooters think about, and even fewer worry about. But it's a good idea to be at least cognisant of it, because it can happen with factory ammunition, as well as handloads. In semi auto pistols it can becaused by 2 basic factors, recoil, and the slide pushing the nose of the bullet into the feed ramp.

This is the exact opposite of what happens in revolvers, where that same recoil can pull the bullet slightly out of its case as it rotates in the cylinder. In revolvers, (especially in the Magnum cartridges), it can be enough to pull the bullet far enough out of its case to tie up the gun.

This doesn't happen much because revolver cartridges usually have a heavy crimp on them to prevent this. And most revolver cartridges headspace on the rim. But semi auto pistol rounds cannot have heavy roll crimps, because they headspace on the mouth of the cartridge. So a taper crimp must be used. And that type of crimp doesn't provide the "grip" a heavy roll crimp does.

A few thousandths of setback isn't going to hurt anything, but the article below states that a setback of just .010 or more can become a problem waiting to happen. And .035 + has the potential to cause a disaster.

I'm not trying to create fear. But it is something most shooters should at least be aware of. And it's quite easy to check for, by simply eyeballing your ammo before you shoot it.

https://www.recoilweb.com/bullet-setback-fears-160844.html

Yeah I loadem long and if loadem to full power or +pee it's a compressed load and therefore bullet set back isn't possible.
Lee factory crimp die is your friend.

 

[Astro14]

Interesting, I didn't know that. I have always done this. But I see what you mean. I don't own a 1911(yet). I don't remember any of my Ruger or my Springfield rdp mentioning not to do this, but I will read up further.

The Ruger P90 manual says you can load one that way. It’s the only manual I’ve ever seen that allows it.

Your Springfield specifically prohibits the practice.

This is part of why I recommend against the practice.

Of the dozens I owned, only one, the P-89, allowed it.

Developing a habit pattern based on one gun, when that habit pattern is prohibited by all the others, is just not a good idea.

By getting used to the practice, you develop a bad habit on the majority of guns. If you were to load one of my 1911s that way when you and I were at the range -

we would have words.

You won’t know that you’ve damaged the extractor until you pull the trigger for the first time.

So, you load your Springfield RDP for defensive use using the “drop one in the chamber” technique.

And the first time you pull the trigger, it goes bang once.

Then it jams, because the extractor didn’t work right. No tap and rack is going to fix this. We’re now in a gunfight with a paperweight.

Probably won’t happen.

But “probably” is simply not good enough for a defensive firearm.

I'm suggesting that you eliminate that possibility by following your owners manual and eschewing that habit.

 

[burbguy82]

The Ruger P90 manual says you can load one that way. It’s the only manual I’ve ever seen that allows it.

Your Springfield specifically prohibits the practice.

View attachment 226006

This is part of why I recommend against the practice.

Of the dozens I owned, only one, the P-89, allowed it.

Developing a habit pattern based on one gun, when that habit pattern is prohibited by all the others, is just not a good idea.

By getting used to the practice, you develop a bad habit on the majority of guns. If you were to load one of my 1911s that way when you and I were at the range -

we would have words.

You won’t know that you’ve damaged the extractor until you pull the trigger for the first time.

So, you load your Springfield RDP for defensive use using the “drop one in the chamber” technique.

And the first time you pull the trigger, it goes bang once.

Then it jams, because the extractor didn’t work right. No tap and rack is going to fix this. We’re now in a gunfight with a paperweight.

Probably won’t happen.

But “probably” is simply not good enough for a defensive firearm.

I'm suggesting that you eliminate that possibility by following your owners manual and eschewing that habit.

I agree, it should not be done, as good practice, but everything causes cancer in California too.

Never mentioned it to you in the past nor anyone really, because I did not want to sound like something I am not, but I have bought some firearms just to destroy them, or at least try to, within the limits of reasonable use, and sometimes unreasonable. One of my XD pistols is one of them.

Maybe I will make a thread on it, with some pictures of the gun.

 

[dubber09]

In most cases setback happens with defensive ammo where a person loads mag, chambers top round, carries, comes back, unloads and puts the round back on top in the mag, repeat this a few times and top round's bullet may go in deeper into case eventually on taper crimped ammo. Roll crimped ammo should be way less susceptive to this.

 

[SubieRubyRoo]

The Ruger P90 manual says you can load one that way. It’s the only manual I’ve ever seen that allows it.

Your Springfield specifically prohibits the practice.

View attachment 226006

This is part of why I recommend against the practice.

Of the dozens I owned, only one, the P-89, allowed it.

Developing a habit pattern based on one gun, when that habit pattern is prohibited by all the others, is just not a good idea.

By getting used to the practice, you develop a bad habit on the majority of guns. If you were to load one of my 1911s that way when you and I were at the range -

we would have words.

You won’t know that you’ve damaged the extractor until you pull the trigger for the first time.

So, you load your Springfield RDP for defensive use using the “drop one in the chamber” technique.

And the first time you pull the trigger, it goes bang once.

Then it jams, because the extractor didn’t work right. No tap and rack is going to fix this. We’re now in a gunfight with a paperweight.

Probably won’t happen.

But “probably” is simply not good enough for a defensive firearm.

I'm suggesting that you eliminate that possibility by following your owners manual and eschewing that habit.

Just tell em… it’s an autoloading pistol, not a bolt-action rifle!

 

[billt460]

Just tell em… it’s an autoloading pistol, not a bolt-action rifle!

You shouldn't load a controlled round feed bolt action that way either, (by putting a round in the chamber). They, (controlled round feed bolt action), should be loaded by pressing a round into the magazine, then closing the bolt, allowing the extractor and bolt face to engage the rim of the cartridge, and feed it into the chamber.... Hence the term, "controlled round feed".

 

[dubber09]

May be Ruger P90's extractor claw isn't as delicate as on many guns and can withstand this, just a guess.