Necked Cases for Reliability

[Justin9999]

I have read about necked cases having higher feed reliability than straight wall cases. As a mechanical engineer, I understand lead-in chamfers and I can see the parallel. As a owner of a .45 ACP Kimber with a 3" barrel, I have experienced feeding issues. However, I have not studied the kinematics of cartridge feeding and I may be seriously mistaken with my thinking that a necked cartridge will lead to increased feeding reliability.
*
I understand that the 357 SIG is mostly manufactured by those who manufacture highly reliable pistols, and I have read about feeding reliability issues with the .40 Super.
*
Is there any serious data that supports or refutes the hypothesis that necked cases lead to increased feed reliability for EDC pistol designs?

 

[barnetmill]

A lot involved in getting magazine fed arms to feed 100%. Now days high speed photography along with advanced software make it easier to analyze failures and make better designs. A better example of a bottle neck pistol cartridge is the 7.62x25 and similar 30 mauser cartridge that is long slender bottle neck rounds used in the construction in millions of submachineguns and pistols from the former east germany to north korea.

 

[CDW4ME]

My 357 Sig Glock 32 and 33 have been very reliable, but so have my Glocks in 9mm, 40, 45, 10mm.

 

[fxvr5]

Feeding from a single stack magazine can present some issues. You might find the article below of interest.

https://americanhandgunner.com/gear/nosedive-and-feed-angle-in-the-1911-45-acp/

 

[tipoc]

It was and still is in some jurisdictions, a selling point for the 357 Sig that it is bottlenecked case, at least in advertisements and gun magazine articles. It was till someone asked..."Well if that's the case why does no one complain that the 9mm does not feed well?" No one complains about the 9mm because it feeds exceptionally well. In fact, so does the 32 acp, the 380, 38 Super, 40 S&W and the 45 acp and more. All of these are straight walled or slightly tapered. If the gun is well built then it will feed 100%. Above that you can't go. So the marketing idea that a necked case increases reliability in feeding is similar to arguing that a black umbrella will keep more rain off you than a red umbrella.

A case can be made that bottle necked cases in some handguns have more issues in extraction than do others.

If we were talking about long guns than bottle necked cases can often feed better especially in automatic rifles.

The point of bottle necked cases is not to aid feeding but to allow for increased pressure in a case of about the same length case. That means increased velocity and energy.

 

[fxvr5]

The point of bottle necked cases is not to aid feeding but to allow for increased pressure in a case of about the same length case. That means increased velocity and energy.

Increased pressure or increased powder capacity at the same pressure?

 

[Gordon]

My .30 Lugers feed much more reliably tham my Martial 9mm Lugers did. I kept the .30 Lugers, they are fun to shoot, I reload led bullets I cast for them !

 

[Riomouse911]

A lot involved in getting magazine fed arms to feed 100%. Now days high speed photography along with advanced software make it easier to analyze failures and make better designs. A better example of a bottle neck pistol cartridge is the 7.62x25 and similar 30 mauser cartridge that is long slender bottle neck rounds used in the construction in millions of submachineguns and pistols from the former east germany to north korea.

The Tokarev rounds and the PPSh were exactly the rounds/subgun I was thinking of when it came to amazing reliability.

Stay safe.

 

[Texas10mm]

I have read about necked cases having higher feed reliability than straight wall cases. As a mechanical engineer, I understand lead-in chamfers and I can see the parallel. As a owner of a .45 ACP Kimber with a 3" barrel, I have experienced feeding issues. However, I have not studied the kinematics of cartridge feeding and I may be seriously mistaken with my thinking that a necked cartridge will lead to increased feeding reliability.
*
I understand that the 357 SIG is mostly manufactured by those who manufacture highly reliable pistols, and I have read about feeding reliability issues with the .40 Super.
*
Is there any serious data that supports or refutes the hypothesis that necked cases lead to increased feed reliability for EDC pistol designs?

Using a 3" 1911 as a baseline isn't the best idea. Get a 5" and you'll see a huge difference.

 

[bassjam]

I highly doubt you'll find any data supporting that claim, you'd need someone with the funds of the US Army to really do a meaningful reliability test. As it stands, modern 9mm handguns are extremely reliable. I can't think of a singe failure to feed issue with any of my 9mm guns, or the 40S&W I had, or my 1911. My LCP can be picky about some hollow points, but it's a cheap tiny pocket rocket, and my SIG P938 and Kahr MK9 haven't suffered the same issues.

Is spending the premium on .357 SIG ammo to get 99.999% reliability really worth it, when a 9mm will give you 99.995% reliability?

 

[JimKirk]

I shoot a Glock 31 .... 357 SIG .... I also have a 9mm Conversion barrel ...

The best of both worlds!

Over 4000 rounds on the 357 SIG never a hiccup...

About a 1000 rounds on the 9mm barrel ....none either....

 

[tipoc]

If necked cases in handgun rounds did actually feed more reliably they would be the go to bullet design by far. But they are not. The numbers of them that are still living and in the market is small. Fact is, it's generally the magazine or the gun that account for issues with feeding and not the round, unless the latter is deformed or damaged. The "they will feed more reliably" is marketing hype.

We can find discussions of this on-line with a quick search.

https://www.quora.com/Why-are-there-so-few-bottleneck-handgun-cartridges

 

[tipoc]

My .30 Lugers feed much more reliably tham my Martial 9mm Lugers did. I kept the .30 Lugers, they are fun to shoot, I reload led bullets I cast for them !

What do you mean by "Martial 9mm Lugers".

 

[TheProf]

I have read about necked cases having higher feed reliability than straight wall cases. As a mechanical engineer, I understand lead-in chamfers and I can see the parallel. As a owner of a .45 ACP Kimber with a 3" barrel, I have experienced feeding issues. However, I have not studied the kinematics of cartridge feeding and I may be seriously mistaken with my thinking that a necked cartridge will lead to increased feeding reliability.
*
I understand that the 357 SIG is mostly manufactured by those who manufacture highly reliable pistols, and I have read about feeding reliability issues with the .40 Super.
*
Is there any serious data that supports or refutes the hypothesis that necked cases lead to increased feed reliability for EDC pistol designs?

1. The .357sig is essentially a tapered cartridge. So, the skinny front part goes in the much wider chamber without much fuss. No scientific data on my part.... Just simple reasoning.

2. Also heard that 1911s of the full size variety is more reliable than shorter 1911...all things being equal. It seems that the more one departs from the original 1911 specs..the more issues.

 

[CDW4ME]

Is spending the premium on .357 SIG ammo to get 99.999% reliability really worth it, when a 9mm will give you 99.995% reliability?

If one (like me) values additional KE the extra cost might be worth it. If one subscribes to they all perform "about the same", probably not.
Glock 19 (mine):
Federal HST 147 gr +P @ 1,044 fps / 356# KE
Federal HST 124 gr. +P @ 1,210 fps / 403# KE
Glock 32 (mine):
Speer Gold Dot 125 gr. @ 1,344 fps / 501# KE
Federal HST 125 gr. @ 1,358 fps / 512# KE

Over 20% more KE than 9mm+P from same length barrel with factory ammo.

 

[Walkalong]

Using a 3" 1911 as a baseline isn't the best idea. Get a 5" and you'll see a huge difference.

My 3” Kimber runs 100%, but you are right, the 5” 1911s have a lot more room for error, the 3” ones have to be done right.

That said, try different mags. Checkmates with hybrid feed lips are good to go

 

[Justin9999]

If one (like me) values additional KE the extra cost might be worth it. If one subscribes to they all perform "about the same", probably not.
Glock 19 (mine):
Federal HST 147 gr +P @ 1,044 fps / 356# KE
Federal HST 124 gr. +P @ 1,210 fps / 403# KE
Glock 32 (mine):
Speer Gold Dot 125 gr. @ 1,344 fps / 501# KE
Federal HST 125 gr. @ 1,358 fps / 512# KE

Over 20% more KE than 9mm+P from same length barrel with factory ammo.

Agreed. I have no interest in 9mm.

 

[Justin9999]

My 3” Kimber runs 100%, but you are right, the 5” 1911s have a lot more room for error, the 3” ones have to be done right.

That said, try different mags. Checkmates with hybrid feed lips are good to go

Do the hybrid feed lips reduce or eliminate nose diving for the first few rounds?

 

[Walkalong]

Mine don’t suffer from it. I am actually running the Kimber mag and two Wilson’s in my 3”. I don’t use any other Wilson’s.

Download your mag by two and see if the nose dives go away.

 

[Texas10mm]

Do the hybrid feed lips reduce or eliminate nose diving for the first few rounds?

Have you tried different mags in your 3"? If not then you really should.

 

[GarrettJ]

With the .400 Corbon in a 1911, I found the bullet would sometimes hang up on the shoulder in the chamber. Straight-walled .45 ACP would run fine.

The Uzi with a semi-auto feed ramp installed runs great in 9mm, .40, and .45. It absolutely will not feed .357 Sig. every round chambered shoves the bullet back onto the case.

Having said that, I’ve got a couple of inexpensive BCA Glock barrels in .357 Sig, and they run well with great accuracy.

That’s been my experience anyway.

 

[barnetmill]

If necked cases in handgun rounds did actually feed more reliably they would be the go to bullet design by far. But they are not. The numbers of them that are still living and in the market is small. Fact is, it's generally the magazine or the gun that account for issues with feeding and not the round, unless the latter is deformed or damaged. The "they will feed more reliably" is marketing hype.

We can find discussions of this on-line with a quick search.

https://www.quora.com/Why-are-there-so-few-bottleneck-handgun-cartridges

There was once a necked down 38-45 ACP design for reliable feeding various bullet shapes including wadcutters. Just how many pistols will feed wadcutters well.

It was created to be a low recoil target cartridge that would function reliably with multiple bullet types, FMJ to cast lead wadcutters without the feeding problems that straight walled pistol rounds sometimes exhibit. The cartridge can be used in standard . 45 ACP magazines.
Bullet diameter: .357 in (9.1 mm)
Parent case: .45 ACP
Case length: .880 in (22.4 mm)

.38/.45 Clerke - Wikipedia

 

[fxvr5]

Nosedive is 'normal' in a single stack magazine due to how the rounds stack in the magazine. The more rounds that are in the magazine, the greater the nosedive. Less rounds means less nosedive, but they nosedive all the same. See the link I posted earlier.

Nosedive is a problem when the gun jams, and then it become obvious. If there are no jams, the nosedive still occurs, we just aren't aware of it.

 

[barnetmill]

Nosedive is 'normal' in a single stack magazine due to how the rounds stack in the magazine. The more rounds that are in the magazine, the greater the nosedive. Less rounds means less nosedive, but they nosedive all the same. See the link I posted earlier.

Nosedive is a problem when the gun jams, and then it become obvious. If there are no jams, the nosedive still occurs, we just aren't aware of it.

Some double stack magazine narrow to almost a single column; this includes submachine gun and pistol magazines. These are called single feed magazine and some think they are less reliable than double feed magazines. I am not sure.

single feed double stack submachinegun magazine.

 

[fxvr5]

It depends on the magazine. The goal is to reduce the nosedive gap (see the article for an explanation). The usual double column handgun magazines have ribs (indentations) that 'squeeze' the front of the rounds as they move from a double column to a single column. When done right, that removes the nosedive gap. But the ribs have to be deep enough to do the job right. That SMG mag shows no ribs to do that. If the nosedive gap is present, the round nosedives.

Para Ordnance double column magazines are a good example. They have different mags for 38 Super and 9mm. If you put 9mm rounds in the 38 Super mag, they have the gap and the rounds will nosedive.

The ribs on the 9mm are deeper and start lower in the magazine body. This effectively eliminates the gap and nosedive issues.

The 9mm's taper is an issue. With many SMG mags, the 9mm mags are curved. This helps to reduce/eliminate the gap. But straight mags have to deal with the taper which increases the gap. 9mms in a single stack straight magazine have a large gap because of the cartridge's taper, and this can produce some awful nosedive. That's a reason why 1911 9mm mags have different design features, like a spacer to keep the rounds forward and a built-in feed ramp. But the gap can be eliminated in a properly designed double stack mag.