Setback in unchambered factory ammo.

[practicaltactical]

I honestly don't consciously look for this but today while rotating my carry ammo I noticed an fresh (previously unchambered) round in the box that was at least 1/8 of an inch shorter than the others in my Federal HST 124gr 9mm carry ammo. I'm guessing this round is unsafe to fire. Should I contact the manufacturer?

 

[Jim K]

First make sure it is the right ammo and not, say, .380 or 9mm Mak. If it is short, I would discard it, not because shooting a short round is dangerous (it really isn't) but because there is something wrong, and I don't like that on general principles. (It might not have any powder, for example, and the bullet could lodge in the barrel.)

Jim

 

[practicaltactical]

Other than the setback in looks like all the other rounds in the box.

 

[JohnKSa]

...not because shooting a short round is dangerous (it really isn't)...

The OP states that the round is about an eighth of an inch (0.125") too short. Depending on the caliber and loading that can absolutely be dangerous.

For example, it has been demonstrated that a tenth of an inch (0.1") of setback in a 180gr .40S&W loading can cause the chamber pressure to double.

http://en.wikipedia.org/wiki/.40_S&W

Hirtenberg Ammunition Company of Austria (at the request of GLOCK, Inc.) determined that, with a .40 caliber cartridge, pushing the bullet back into the case 1/10 of an inch doubled the chamber pressure.​

http://www.thegunzone.com/glock/kb-notes.html

"“"This was first confirmed via a European cartridge maker (Hirtenberger in Austria) from information given to me by a high level Glock representative. 1/10" set back can cause pressures to double from 35,000 psi to 70,000 psi."​

And from a different source but quoted in the same link.

"I can talk to you about bullet set-back… but let me just say that if you are using a .40 S&W caliber weapon, that tests have been conducted that show very little set-back has raised pressures around 60-70,000 psi (way above a proof load). This could cause, and has caused, weapon blow-ups in the .40."

Dean Caputo, Sgt. - FTU Rangemaster, Arcadia Police Department”​

I don't know of any cartridge where doubling the chamber pressure from a standard pressure loading would not be dangerous in at least some firearms.

 

[practicaltactical]

It was severe enough for me to notice and at least 1/8 ; I think I'll contact the manufacturer on this one.

 

[JohnKSa]

To be clear, I'm not saying that firing the particular round you have is definitely dangerous because I don't have information on how the 9mm 124gr loading is affected by setback. For the same reason I can't tell you it's definitely safe to shoot it.

I was responding to the more general comment that shooting a short round isn't dangerous. While it certainly can be dangerous under the right (wrong) circumstances, that general truth may or may not have any significant bearing on this specific situation.

The only thing that can be said that will be generally true is that setback will increase discharge pressure, all else being equal. How much the pressure increases depends on a lot of things.

 

[ljnowell]

First make sure it is the right ammo and not, say, .380 or 9mm Mak. If it is short, I would discard it, not because shooting a short round is dangerous (it really isn't) but because there is something wrong, and I don't like that on general principles. (It might not have any powder, for example, and the bullet could lodge in the barrel.)

Jim

Not dangerous? Thats EXTREMELY DANGEROUS! I think sometimes that all shooters, even if they dont reload, woudl benefit from reading The ABC's of Reloading.

 

[YankeeFlyr]

Yeah, no way I would shoot it. Ever.

Retain it and bring it to the manufacturer's attention.

THEN....check all the other rounds in the box(es) that were acquired together. Maybe a bad lot, eh?

 

[Lost Sheep]

First make sure it is the right ammo and not, say, .380 or 9mm Mak. If it is short, I would discard it, not because shooting a short round is dangerous (it really isn't) but because there is something wrong, and I don't like that on general principles. (It might not have any powder, for example, and the bullet could lodge in the barrel.)

Jim

Understanding internal ballistics is important.

The REASON why shooting a round with the bullet seated deeper is that, with the volume under the bullet has a major effect on the pressure buildup, particularly as the bullet is just starting to move. Smaller volume, bigger pressure curve.

Most reloaders have a bullet puller that could with a few raps pull the bullet out to the proper position. If you know someone who reloads, you could ask, or just give them the bullet. They could pull the slug, dump the powder (makes good fertilizer, with all that nitrogen in it) and re-use the primed brass. Short of that, your local police will be happy to toss it in their disposal pipeline, I am sure.

Many people carry in condition 3 just to avoid the repeated chambering of rounds and the possible setback that may occur. Others avoid emptying their chambers. I don't endorse either practice.

Lost Sheep

 

[practicaltactical]

I appreciate the replies. I most certainly checked all the other rounds and it's just the one. I'm going to alert the manufacturer and then dispose of the round (responsibly and without firing it).

I have reloading equipment but generally don't use it as time and patience just don't allow. Not to mention, I would never carry reloads. This just got me wondering how many rounds like this I've possibly fired over the years. I'll definitely pay more attention in the future.

 

[italy4nra]

I have had that also in one of my s&b fmj 9mm. Asked at the range and they said it happens rarely, I might even have done it myself. In any case I did not fire it. Textbook says it is dangerous. Some range guys said no problem, most said 10 cents that it is not worth a hand or eye.
Brought it home pulled it apart with a kinetic hammer, tossed the powder, tossed the case went into buckets for reloading.

 

[italy4nra]

I appreciate the replies. I most certainly checked all the other rounds and it's just the one. I'm going to alert the manufacturer and then dispose of the round (responsibly and without firing it).

I have reloading equipment but generally don't use it as time and patience just don't allow. Not to mention, I would never carry reloads. This just got me wondering how many rounds like this I've possibly fired over the years. I'll definitely pay more attention in the future.

When I buy commercial ammo and open the box at the range. I always do a quick visual inspection, while at the same time running my pointer finger lightly over the whole stack of 50 (or 20). With bulk it is harder, but with packaged it is easy to find any setback and it takes only a fraction of a second (plus running your finger over the nose is a nice feeling).

LRN can leave lead on your fingers, even if most have a coating, so be careful with that too! Don't check windsge adjustment with a wet finger if you have checked your lead rounds! ;-)

 

[Drail]

If just one round is visibly out of spec then the whole box will be returned if I bought it. It means someone is not doing their job and with live ammunition that is NOT acceptable. Some of the junk the ammo companies are selling nowdays is truly frightening.

 

[rcmodel]

Thats EXTREMELY DANGEROUS!

Is it?

How many rounds do you think all of us have fired that set back during feeding and we never knew it?

Factory pressure testing has to take setback into account, because it often happens and we don't even know it.

If I did know it, I probably wouldn't shoot it.
But what you don't know happens with factory loads won't likely hurt you or the gun.

If it were blowing up guns, there would be a recall.

rc

 

[Ol` Joe]

Is it?

How many rounds do you think all of us have fired that set back during feeding and we never knew it?

Factory pressure testing has to take setback into account, because it often happens and we don't even know it.

If I did know it, I probably wouldn't shoot it.
But what you don't know happens with factory loads won't likely hurt you or the gun.

If it were blowing up guns, there would be a recall.

Sorry RC but I have to disagree with you here.
There has been more then a couple reports of the danger of setback in straight walled ammo. It takes very little bullet movement to alter the volume of the case which is for all actual purposes the "chamber".
I doubt the factories take account of possible COL varation in their ammo. They don`t know how much they need to deal with or what the pressure will actually be due to other factors such as temp, throat geometry, etc. I believe the best way to handle this is to avoid it if at all possible. I shoot my old ammo when rotating and fill my magazines/cylinders with fresh.

Here is a page from the VithiVouri manual on it. (The bottom paragraph and chart)
100 MPa =~ 14000psi according to this conversion site http://www.convertunits.com/from/Mpa+100/to/psi



Ramshot also warns about varying setting depth on their web site

18. Does the COL/AOL affect the internal ballistics?

It depends on the specific dimensions and capacity of the caliber and the proportion of the change. In the case of handgun calibers a 0.025”/1.0mm difference can have an affect as severe as 20% on the Peak pressure. However, that same amount in the case of a rifle caliber, which is much longer, will have a very small to insignificant effect.

 

[ljnowell]

Is it?

How many rounds do you think all of us have fired that set back during feeding and we never knew it?

Factory pressure testing has to take setback into account, because it often happens and we don't even know it.

If I did know it, I probably wouldn't shoot it.
But what you don't know happens with factory loads won't likely hurt you or the gun.

If it were blowing up guns, there would be a recall.

I normally agree with you RC, but not on this one. An 1/8" setback is more than enough to destroy a handgun, especially something that already runs at a decent pressure, like a 9mm or 40S&W. How you can consider it anything other than dangerous is frankly beyond me. Dangerous doesnt mean it WILL blow up, but it sure has an exponentially highjer probability considering how it affects pressure.

 

[practicaltactical]

I think the lesson here is vigilance. Dangerous tools require our utmost attention to detail and anything less is eventually prone to error. It's not whether or not THIS round was dangerous but rather was there an inherent danger in this situation.

I think this is an unacceptable risk and will, from this point forward, visually check all rounds prior to firing. Given the choice I think any of us would err on the side of safety and after all I didn't have to measure my rounds with a micrometer to notice the difference in case height (in the factory packaging; bullet down).

This is a lesson learned for me without the medical expense. If you are in doubt I would suggest you start here http://en.wikipedia.org/wiki/Situation_awareness

 

[BCRider]

Rcmodel, I've got to disagree with on the OAL and effect on pressure as well.

When I was playing with reloads to meet IPSC Minor I messed around with bullet seating and OAL since my CZ Shadow is sensitive to overly long OAL's.

I found that a mere .010 was enough to produce roughly a 50 fps difference in velocity with no other change in 9mm rounds. This change indicates how the pressure in affected and how little it takes to see real results. Based on this I do not doubt that a .125 setback would produce a huge jump in pressure and with a stout load could easily result in the peak pressure being higher than the SAMMI max pressure.

 

[rcmodel]

I wasn't talking about reloads with unknown powder burn rate.
I was talking about factory loads like the OP was talking about.

I don't think the factory lab rats overlooked the possibility of set-back in powder selection and charges during pressure testing.

It happens more often with factory loads then most of us suspect.
With no disastrous results.

If a factory load sets back during feeding and you shoot it, and the gun doesn't blow up?
You never knew it happened, right?

rc

 

[ljnowell]

I wasn't talking about reloads with unknown powder burn rate.
I was talking about factory loads like the OP was talking about.

I don't think the factory lab rats overlooked the possibility of set-back in powder selection and charges during pressure testing.

It happens more often with factory loads then most of us suspect.
With no disastrous results.

If a factory load sets back during feeding and you shoot it, and the gun doesn't blow up?
You never knew it happened, right?

rc

Nor would you with a handload, but thats besides the point. I do not believe for a second that the factory considers setback when developing the load. In fact, I called a relative who has worked for Olin his entire life and asked him about it. He told me that any setback in a 9mm wichester round would be cause for extreme caution. In order for it to not cause a pressure problem itt would have to be some of the most mild 9mm you would notice it when it didnt have setback, radically.

There is no rational argument that ammunition that has 1/8" setback is not dangerous. Because it doesnt destroy one gun does not mean it wont destroy another. There is no way to predict the pressure.

 

[Drail]

If any ammo manufacturer believes that loose case neck tension allowing bullets to shift is "acceptable", then I most definitely wouldn't touch any of their products with a ten foot pole.

 

[Jason_G]

I've had fresh, out-of-the-box Speer Lawman ammo (.45 ACP) where the ammo in one corner of the box was severely set back. OAL looked to be about 3 mm or so shorter than the other rounds in the box. It kind of looked like someone set something really heavy on one corner of the box, and squished the bullets back into the case, except the box itself wasn't crushed or anything.

It was free ammo, so I shot the rounds that weren't set back and tossed the others.


Jason

 

[BCRider]

I wasn't talking about reloads with unknown powder burn rate.
I was talking about factory loads like the OP was talking about.

I don't think the factory lab rats overlooked the possibility of set-back in powder selection and charges during pressure testing.

It happens more often with factory loads then most of us suspect.
With no disastrous results.

If a factory load sets back during feeding and you shoot it, and the gun doesn't blow up?
You never knew it happened, right?

rc

Come on rc, you know better than this.

A few thou? Not a big deal. As I found it makes a difference but not a lot one way or the other. But enough of a setback amount to easily see the change when handling the ammo? That's enough to produce a big shift in pressure regardless of what the burn rate of the powder may be. ESPECIALLY when it's a small volume semi auto casing such as a 9, .40 or .45.

And when we start talking about a 1/8 inch amount on a 9mm that's a HUGE amount of change. The burn rate of the powder doesn't enter into it.

Ya know.... if factory ammo can suffer from such a situation it might even explain some of the Glock and various other KB's that don't seem to have any other explanation. A few loose bullets get set back a little too far due to recoil while in the mag and suddenly KB! ! ! ! It would be interesting to hear from those that have suffered from otherwise unexplained KB!'s if it was early or later in the mag when the disaster occured.