Bullet Setback

[Bigguy]

This is an embarrassing post to make. I'm confessing my ignorance and the ignorant actions that almost got me into trouble. Non-the-less, I don't want to let my pride stop me from posting on a topic that might help somebody else. While I'm sure most of the member who routinely post here are already aware of this, there may be other folks, who like me lurk more than post, and might be unaware of this potential danger.
I'll copy my original post below, but there is a lot of good information in the responses from other members. I'm sure some of the knowledgable people here will also contribute valuable advice.


Bullet setback thread on Texas CHL forum (http://texaschlforum.com/viewtopic.php?f=23&t=65850)
I want to thank the CHL and it's members. Specifically those responding to the thread "Carrying With One Loaded In Chamber (Question?) (http://texaschlforum.com/viewtopic.php?f=53&t=65350&p=802101&hilit=a+round+in+the+chamber#p802101)
Somebody asked about leaving a round in the chamber. They had heard that it somehow damaged the cartridge.
I had developed the routine of ejecting the magazine every night, racking the slide to eject the chambered cartridge. I'd then hold the muzzle to a lamp so that light shines down the barrel, demonstrating no obstruction. I'd do a quick visual, then reinsert the magazine and release the slide lock, confirming the mechanisms fed properly. I'd then eject the magazine again and reload the cartridge, previously in the chamber, back into the magazine. Basically I was recycling two cartridges back and forth between the chamber and the top of the magazine. After reading that thread I decided to check my gun. Here is what I found:
http://www.guywheatley.com/photos/Two_nines.JPG
The cartridge on the right is one of the two I'd been rotating with my nightly routine. The one on the left is fresh from the box.
You guys may have saved me from injury. I spend quite a bit of time on this, and the Pistol Forum (http://pistol-forum.com/forum.php) in order to learn from knowledgeable people talking about guns. While it's embarrassing to write about my ignorance and ignorant actions, I decided to swallow my pride and fess up in order to thank you guys and let you know that there is real good in the exchanges between you on this board.

[Dave J]

Consider obtaining some sort of lockbox for your carry gun. If you remove the gun from your person, simply leave it loaded, and lock it up.

I'd suggest using a dedicated container for this, rather than mixing loaded and unloaded guns together in a larger safe.

If you must download, the round from the chamber goes in the training pile. If I am short on carry ammo for some reason, I'll mark the cartridge with a Sharpie, and chamber it no more than one additional time.

And thanks for posting that picture! I'm sure it will help drive the message home. (If you don't mind, I'd like to copy that picture, and add it to my teaching slides)

[Bigguy]

(If you don't mind, I'd like to copy that picture, and add it to my teaching slides)
I don't mind at all. I'm grateful for the opportunity of assist in a teaching opportunity.
I don't need photo credit for it though.:p

[Jay585]

Thanks for posting this.

I'm curious - what happens if one were to fire the reduced-OAL round?

[EricP]

Thanks for posting this.

I'm curious - what happens if one were to fire the reduced-OAL round?

Chamber pressure skyrockets. In my one experience, it blew the magazine out of the gun, felt like someone hit me in the hands with a bat, and scared the living kittens out of me.

Mine wasn't from rechambering the same round, but what I suspect was missing the crimping stage of assembly.

[Chuck Haggard]

Someone thought that leaving a round in the chamber damages the cartridge?

Seriously? I'm not trying to be an ass, I've never heard that one before.


Clearing the gun daily is a really bad idea, FAR better to use a lock box.


Also, you are carrying FMJ as carry ammo?



And yes, set back can more than double chamber pressure and blow up the gun. I have seen several LE advisories over the years ref blown up guns, mainly from agencies that insist on loading/unloading a lot, like the guys that guard the nuke plants.

Even if you do not get set back you can end up damaging the primer internally and have a dead round. I have seen a couple of LE advisories on this as well. I also know a guy who had a bad day in Iraq, tries to shoot a bad guy, M4 goes click, transition to Glock 19, G19 goes click. Fortunately he was squared away and got the guns running and finished the problem.

[Chuck Whitlock]

Someone thought that leaving a round in the chamber damages the cartridge?

Seriously? I'm not trying to be an ass, I've never heard that one before.


Clearing the gun daily is a really bad idea, FAR better to use a lock box.


Also, you are carrying FMJ as carry ammo?



And yes, set back can more than double chamber pressure and blow up the gun. I have seen several LE advisories over the years ref blown up guns, mainly from agencies that insist on loading/unloading a lot, like the guys that guard the nuke plants.

Even if you do not get set back you can end up damaging the primer internally and have a dead round. I have seen a couple of LE advisories on this as well. I also know a guy who had a bad day in Iraq, tries to shoot a bad guy, M4 goes click, transition to Glock 19, G19 goes click. Fortunately he was squared away and got the guns running and finished the problem.

Besides the LE advisories, the info is in the archived newsletters at rangemaser.com.

[littlejerry]

I have never fired a round with a bullet setback in the case as shown in the photo. I would not recommend doing so either.

However,
Luckygunner Labs posted this report where they set a .40 S&W as far back as possible in a case and fired it, multiple times, without any adverse effects on a Glock 22.
https://plus.google.com/+luckygunner/posts/CiVxdHvWjYS

[EMC]

I have never fired a round with a bullet setback in the case as shown in the photo. I would not recommend doing so either.

However,
Luckygunner Labs posted this report where they set a .40 S&W as far back as possible in a case and fired it, multiple times, without any adverse effects on a Glock 22.
https://plus.google.com/+luckygunner/posts/CiVxdHvWjYS

Gotta love Luckygunner labs, the mythbusters of the gun world.

[Bigguy]

Also, you are carrying FMJ as carry ammo?
Another reason to be embarrassed. I'll snag the first box of JHP I can find. I do have JHP Gold Dot for my .380 BUG.

[JAD]

Ironically, if I had a .380, I'd carry FMJ in it.

[DocGKR]

As I've stated numerous times, Once a round has been chambered, DO NOT RE-CHAMBER IT for duty use. Do NOT re-chamber it again, except for training. This is CRITICAL!!!

A large SWAT team in this area had a failure to fire from an M4 with Hornady TAP ammo during an entry--fortunately no officers were hurt and the suspect immediately threw down his weapon when the carbine went click instead of bang. After the incident was concluded, the team went to the range and expended the rest of their carbine ammo and had one additional failure to fire. This same team had 3 Hornady TAP rounds fail to fire in training a couple of years ago. When Pat Rogers was teaching a class at a nearby agency, there were 5 failures to fire using Hornady TAP ammo. In all 10 cases, there appeared to be good primer strikes, but no rounds fired. On analysis, the ammunition had powder and checked out otherwise.

http://i459.photobucket.com/albums/qq319/DocGKR/BadSWATPrimers.jpg?t=1330507084

However, despite what appeared to be good primer strikes, two problems were discovered. First, when accurately measured, some of the primer strikes had insufficient firing pin indentations. The failed round from the potential OIS incident had a primer strike of only .013"—the minimum firing pin indent for ignition is .017". In addition, the primers on the other rounds were discovered to have been damaged from repeated chambering. When the same cartridge is repeatedly chambered in the AR15, the floating firing pin lightly taps the primer; with repeated taps, the primer compound gets crushed, resulting in inadequate ignition characteristics--despite what appears to be a normal firing pin impression.

Rechambering pistol ammunition can also cause issues, including both failures to fire from primer damage and increases in pressure as a result of bullet set-back: http://le.atk.com/downloads/technical_bulletins/357_SIG_Setback_Length-vs-Pressure.pdf

The comment below is written by a highly skilled combat veteran I know regarding his experience fighting OCONUS with ammo that had been re-chambered:


"I have relayed this story to a few of you before but here it is again. Pay attention to what DocGKR has stated because it could very well save your life. My first shooting in Iraq I threw my M4A1 on semi and ATTEMPTED to fire a controlled pair (First round functioned striking the threat and the second round did not function). I then transitioned to my secondary (Glock 19 shooting ball) and had a failure to fire on my first round....I was Waaaaaay behind the power curve at this point. At this point I was contemplating all of my various bad life decisions which had lead me to that point in my life and grabbed an M240B and solved the problem. I AM VERY LUCKY TO STILL BE UPRIGHT AND BREATHING TODAY....the cause of these malfunctions you ask? Repeated chamberings of the same ammo. I made a decision that day that my life was more important than following archaic rules written by those who sit behind desks and started shitcanning rounds after i was forced to clear weapons on U.S. Military installations. The .gov can fuckin bill me."

In addition, as noted above, DOE security personnel have noted this same issue, not only with carbines, but also with .40 Glocks.

A person might get away with re-chambering several times, but it could also kill the primer or intrude the projectile into the cartridge case in as little as 3 re-chamberings. Is a life worth the cost of a single cartridge?

Keep the pistol in your holster, remove the holster from your belt and place it in the lock box. When you need the pistol again, re-attach the holster to your belt.

[ToddG]

Keep the pistol in your holster, remove the holster from your belt and place it in the lock box. When you need the pistol again, re-attach the holster to your belt.

That's what I do.

As for the Luckygunner Lab thing, there are a lot of factors that need to be determined. Powder charge, bullet design, etc. can all affect the pressure of an overseated bullet. In the instant case, e.g., if it was the low-pressure 165gr "Reduced Recoil" Gold Dot which is popular with many LE agencies then the overseating would be much less likely to cause as dangerous a spike as, say, a round loaded to max pressure.

Suggesting that it's not dangerous based on one backyard test is, imho, irresponsible. There are far too many people with personal experience of overpressure/overseated rounds causing substantially damage to shrug it off as a myth. If you read the comments, for example, there is one person who said he's seen serious overseating with his 357 SIG Gold Dots and apparently, thanks to Luckygunner, won't be worried about shooting them. I've worked with two large federal LE agencies that have suffered multiple damaged guns from shooting 357 SIG Gold Dot with just a few chamberings per round. One of those agencies also all but destroyed an entire shipment of guns early in the days of 357 SIG with another brand of ammunition that had particularly serious problems with maintaining neck tension.

When I go to the range, the first round I fire is the round that was in the chamber when I drove there whenever possible. If for some reasons I'm forced to clear my pistol prior to shooting, the JHP gets put somewhere specifically designated for once-chambered JHPs and gets fired as a practice round at my next opportunity. That way:

it never gets chambered more than twice, and
I never rely on it for self-defense once it's been chambered more than once.

[J0hnny]

32386

I was casually loading mags before heading to the range today and pulled this round from a new box of 124gr Lawman. A good reminder to actually look at what you’re putting in your mags.

[OlongJohnson]

I always check the height of all the rounds in the rack when I pull it out of the box. I've seen one where an edge row was progressively set back further as you went toward the end of the row. Almost certainly dropped on that corner.

[J0hnny]

I think you’re right as it was the last round in the box. But it sure may me unload the rest of my mags to check


I always check the height of all the rounds in the rack when I pull it out of the box. I've seen one where an edge row was progressively set back further as you went toward the end of the row. Almost certainly dropped on that corner.