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Discussion Starter · #1 ·
I have a new MC Operator, and have noticed that the duty rounds that I dump out of it tend to be pushed back into the case. What is the cause of this? I'm new to this weapon system...and appreciate any input!
 

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Chambering a round in a 1911 can be a violent affair. Some 1911s are harder on cartridges that others due to variances in tolerance and manufacturing. Excessive bullet setback can be potentially dangerous, especially with +P loads. If you are getting bad setback with all of your factory rounds after just one or two chamberings, your pistol may have an issue.
 

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Setback is common a common topic on this forum.

I've posted this information before:


The ammo is the most common culprit for setback, and results from insufficient neck tension. That said, setback itself is common, and the degree of setback from one chambering varies from none to 0.035" in my experience with 45 ACP ammo. My test of 240 rounds of factory 45 ACP ammunition showed a setback rate (of greater than 0.001") of 75% after a single chambering. The average setback was 0.010".

The largest setback I observed was a round of 9mm that moved 0.105" on a single chambering. Yikes!

The highest average amount of setback was with 40 S&W and 357 SIG which averaged 0.026" (a total of 16 rounds tested for each caliber).

I measured a total of 347 rounds all fed through single column 1911s. Calibers included 45, 40 S&W, 10mm, 357 Sig, 38 Super and 9mm Luger. All ammo was factory. All of the rounds tested with 40 S&W, 10mm, 357 Sig and 38 Super showed some setback (greater than 0.001"). The 9mm Luger had a setback rate of 97%.

Keep in mind that chambering a round is a violent process. Setback, to some degree, should not be unexpected. Rounds that have severe setback should not be fired, but I can't give you a number for what constitutes severe setback. Use your judgement.
 

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Discussion Starter · #4 ·
These are factory rounds, Hornady XTP 200gr...the "brown box" stuff. The bullets themselves have no cannelure on them, which may account for the ease at which they slip back. I guess that when I start reloading soon, I'll have to use bullets with cannelures on them!
 

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Discussion Starter · #6 ·
Also-I'm sorry if this has already been addressed; I'm not that computer-savvy... but I do appreciate the quick response! Is this something that will get better as I shoot my weapon? It has less than 150 rounds through it...
 

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Setback won't change much since it is more a function of the ammo than the gun. Some factory ammo is prone to setback, while some isn't.
 

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Is this something that will get better as I shoot my weapon? .
probably not.
trying a different style/brand mag might ..like a Wilson
also, the first rnd in a full mag will set back more than the last rnd because it hits the feed ramp lower

if you need to unload and load often, "ride the slide" to load it.
(yea we all know that's not how a pistol functions) ..so what
just be sure the rnd chambered and slide is fully in battery


..L.T.A.
 

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cjmj26, as Cappi pointed out, if you frequently must unload and re-chamber your rounds, then ride the slide to allow the loading round to gently slip into the chamber. Also, rotate the current set of carry rounds to ensure that you are not re-chambering the dame round all the time. In addition, frequently check your rounds for set back. You can keep a cartridge of known proper length for comparison, or you can buy a cartridge length gauge. http://www.lymanproducts.com/lyman/case-prep/pistol-max-gauge.php I find that 1911s with proper frame and barrel ramps and good magazines load a cartridge quite easily while riding the slide, allowing the cartridge to gently slip right into the chamber. Other 1911s, however, often allow the feeding cartridge to stick nose first on the frame ramp, requiring some force to be applied to the slide to complete the chambering process. How easy your pistol loads with a ridden slide will indicate how well your pistol is put together. Regardless, in my experience, riding the slide and keeping a check on your rounds for set back will keep you out of trouble.
 

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Discussion Starter · #10 ·
cjmj26, as Cappi pointed out, if you frequently must unload and re-chamber your rounds, then ride the slide to allow the loading round to gently slip into the chamber. Also, rotate the current set of carry rounds to ensure that you are not re-chambering the dame round all the time. In addition, frequently check your rounds for set back. You can keep a cartridge of known proper length for comparison, or you can buy a cartridge length gauge. http://www.lymanproducts.com/lyman/case-prep/pistol-max-gauge.php I find that 1911s with proper frame and barrel ramps and good magazines load a cartridge quite easily while riding the slide, allowing the cartridge to gently slip right into the chamber. Other 1911s, however, often allow the feeding cartridge to stick nose first on the frame ramp, requiring some force to be applied to the slide to complete the chambering process. How easy your pistol loads with a ridden slide will indicate how well your pistol is put together. Regardless, in my experience, riding the slide and keeping a check on your rounds for set back will keep you out of trouble.
Thanks for all the answers! I'll trying riding the slide home and see if that helps...I'm under the impression that the weapon is put together well-I'm very pleased with the frame to slide fit and the workmanship thus far. I ran it through a bunch of drills today and it functioned perfectly-thanks again!
 

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semi-auto bullets don't have cannelures. neck tension holds the bullets in place to prevent/reduce setback.
I hadn't seen that either, until I bought some Hornady Eraser Tops (Critical Defense?) I don't load/unload very often, so I don't know if this would help the setback issue.



 

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I've learned that Hornady self defense loads don't hold up to multiple chamberings well at all.
 

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If you believe all printed advertising, I just read this on the Hornady site...

"Bullets are cannelured and crimped to avoid bullet setback."

But I would be more inclined to believe Snakeshooter17. If that rubber contacts any of the ramp, not exactly friction free.
 

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Having a gripper on the front of a bullet might not be the best idea.. Frequent loading and unloading isn't either, best to just shoot the loaded round. Cheers..
 

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Semi-auto bullets don't have cannelures like revolver bullets do. Of course, there are going to be exceptions, but they are the exceptions. But semi-auto bullets don't utilize them because semi-auto cartridges are crimped in a different manner than revolver cartridges.

Revolver cartridges use a roll crimp and the case mouth is pushed into the cannelure. This is okay since revolver cartridges headspace on the rim, i.e. the rim stop the cartridge from entering the chamber too far.

But semi-auto cartridges headspace on the case mouth, i.e. the case mouth stops the round from going too far into the chamber. Using a roll crimp on a semi-auto cartridge can cause malfunctions/accuracy problems because the case mouth no longer stops the cartridge's movement - some part of the "roll" does. Semi-auto rounds use a taper crimp, and folks here debate how much that should be, from none to no more than -0.002". So, different bullets because of different headspace mechanisms.

That said, it is possible to use cannelured bullets in your semi-auto cartridge. Just use a taper crimp as you would normally and your gun (chamber) will not be able to tell them apart.
 

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Hornady's plastic tip insert is fine as long as it stays flush with the top of the bullet. If it does that, it will not contact anything during the feeding process. But if it projects from the tip and contacts the feed ramp during feeding, the problem begins because it is soft and has a poor friction coefficient.

The best bullet nose is hard so it can slide along or bounce off the surfaces it contacts. Hard is good. Soft is bad. (I'm talking about bullets here!) Swaged and plated bullets are soft and sometimes have problems feeding because they don't slide along or bounce off surfaces as well. Some act downright sticky!
 

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It's not just the CD line of Hornady loads. The TAP FPD loads I picked up for my Sig got pretty bad really fast.
 

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A ramp and throat job performed by a competent smith virtually
eliminates set-back concerns.
 

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A ramp and throat job performed by a competent smith virtually
eliminates set-back concerns.
I've noticed this, too. My Commander has a very smooth feed ramp and barrel dimple, almost mirror-like. I rarely have a setback in my loads. It takes many chamberings and the pistol runs very, very smooth compared to other 1911s I've run.

Chuck, you work on a lot of Colts. What do you think of the "dimple" that they use, rather than completely throating the entire half of the barrel?
 

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The dimple works well.
A good smith will extend a very similar configuration from 10 to 2 o'clock.
That works even better!
 
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