Rechambering Rounds

[downzero]

I am required by my wife to "unload" and lock up my guns.

Yes. With our children she would rather have it unchambered and in the safe.

It sounds like your wife is a threat to your personal safety. It's a surprise that she wasn't aware that you took your safety seriously before you married her.

If my wife made me unload my guns, I would carry a revolver until I could get rid of her and marry someone who wasn't irrationally afraid of inanimate objects.

Certain compromises are necessary in any relationship, but I would not live anywhere where I could not have any firearm available for self defense. A wife who requires you to live like that needs to seriously reconsider her wedding vows.

 

[PeaShooter]

Ask her how you are supposed to protect your family, if your gun is in the safe, unloaded?

 

[TomN]

True. but my kids are notorious for doing stupid things. If they want to see the guns, I let them. But at 2 and 4, they are hardly trustworthy yet.

I've got younger kids so I totally understand this, but how would they get into the safe?

 

[SmileDocHill]

So, is your safe something the kids could realistically get into at that age? Serious question because there are a lot of variables that play into it. Kids are different and safes are different.

Unlike preventing theft, kids are in your house all the time and present some additional issues. If there is a key to it you simply cannot rely on hiding something (the key) from kids. Keys present a constant issue of keeping them on your person and then committing to never sleeping or figuring out the super secret hiding place that is ALSO accessible enough to make the gun realistically retrievable in a certain time frame. If it is a combination lock then you have to either commit to memory and destroy the manual with the combination or you are back to hiding something.

My point is that if the gun is locked away from the kids I don't see the additional safety value in also unloading it.

 

[wizard_of_ahs]

If you're putting the gun in a lock box why do you unload the gun?

If there's no earth-shattering reason to unload it, I'd just keep it loaded.

But if you have to unchamber a round every evening, make sure that you rotate the rounds that you're chambering in the gun so you don't get that bullet setback. Also if you can, check the rounds you are chambering with ones that you're not. If you see the rounds getting shorter stop running them through the gun and toss em just to be safe.

I keep my carry gun loaded at all time...

Ask her how you are supposed to protect your family, if your gun is in the safe, unloaded?

You better hope you NEVER need it

 

[Mr. Habib]

Perhaps the safest solution is to lock your wife in the safe when firearms are present.

 

[KG1]

I get the part about putting it in the safe but I think it was mentioned already that you are at a much greater risk of an AD whenever you chamber/un-chamber a round then if you were to leave it loaded and secured in a safe.

 

[mrortega]

Max/Min OAL must not be in your manual either

Well, duh. Of course the overall length is given because there are standards on chamber length and the round has to fit the "standard" chamber. As far as the minimum is concerned I don't know the reason for that except too little space will increase pressure. However, I doubt that it is possible to come up with a table to tell what the pressure would be with different lengths of bullet seating.

 

[BravoMike]

This may help answer your first question.

Thank you, that helps. Are there charts for other calibers? My google fu is weak. I could only come up with the chart that you found above.

Help me with these definitions please (in layman terms).
SAAMI Proof Pressure - The maximum pressure before your barrel is turned into a pipe bomb.
SAAMI Maximum Average Pressure - The max recommended pressure that SAAMI recommends on repeated firing to not cause undo stress on a barrel that would lead to mechanical failure.

 

[Mr. Habib]

That is the only chart like that that I've found. I find it interesting that the chamber pressure actually decreases after a certain length is reached. I believe that's due to the powder being compressed to the point that the burn rate is retarded, but that's just my best guess.

Your definitions look good to me.

 

[downzero]

Someone should also point out that this is a stupid question. Why would you tempt fate by repeatedly chambering a round? Even if you know how much setback it experienced, the only question is whether your particular barrel holds up to that round being fired. Statistical answers don't help you when the bad guy is in front of you and your gun blows up in your hand. Taking unnecessary risk with a gun you may need to use in an absolute last-resort situation just doesn't seem very smart at all.

It's kinda like putting a lighter hammer spring in a self defense gun. Even if you knew that 999 out of the last 1000 rounds went bang, what if the next one didn't? Why do something that you KNOW increases the risk of your self defense firearm being less effective, even if the chance is small? The magnitude of something like that is a catastrophe.

Think about this: the only way to find out the answer to this question, as it applies to you, is to be in a situation where you reasonably fear death or serious bodily injury if your gun does not fire. In that situation, how much time do you think you're going to have to draw another gun, run away, or take some other action to save your life if the situation is THAT dire? Or are you prepared to be that close to being able to save your life, but to lose it instead?

We all carry guns knowing that the chances of needing them are tremendously slim. But why would you possibly stack the deck against you in an unprovoked, defensive gunfight? Your attacker already has the upper hand because he knows when he's going to attack and he decides how and when. Having your equipment prepared in this situation is just not optional.

 

[eldirector]

Just for fun, I fired up the Google machine.

Did find an interesting little "test":
Semi-auto Setback Testing

Harder to find pressure v. setback like the graph above.

 

[JettaKnight]

I am required by my wife to "unload" and lock up my guns.

By "unload", you mean unload, right?

This is ridiculous. Every time you coonfinger this gun there's a chance for a discharge.

Do you have a sand barrel? If not, where's that bullet going to stop?

If your worried about kids getting into your safe then really isn't safe, is it?

But enough beating up on you, if I was in this situation I'd
- have a box that each round would go into when I emptied the chamber.
- In the morning, I'd grab a fresh round from a new box, load it on top of the magazine then rack it into the chamber.
- Repeat until no new rounds in the fresh box.
- Now remove all rounds from the magazine and place in fresh box.
- Reload magazine with used rounds.
- Continue process unitl fresh box is empty again.
- At this point, all rounds have once loading cycle.
- Dump the used rounds in the fresh box and repeat this whole process as many times as you dare.

Take measurements and let us know the results.

 

[JettaKnight]

Does how aggressively you rack the slide affect the setback?

 

[BravoMike]

The reason I have been curious about this is because I keep on reading on the interwebs that if you rechamber your SD round, your gun will blow up.

I am a bit of a skeptic when it comes to this as there are many gun "myths" that are fallacies. I have read where there have been cases of guns blowing up for numerous reasons, but never because of bullet setback. It appears that most of them time it is in fact a problem with the ammo, but for many other reasons.

I shoot my SD pistols on a regular basis (M&p 9c for carry and Fullsize for the home) and unload and reload when at the range, then again at home for cleaning. Often I will just unload the cartridges from my spare mag and when done, reload my carry gun by rechambering with the top bullet of the mag. This means that the top two bullets get rechambered many times. I re-supply my SD loads about once a year. I just ordered some Speer Gold Dots from sgammo.com at ~$65 for 100 rounds, which I think is a pretty good price.

I might be wrong but I think most of us probably have a similar routine that I described above. It is also very costly for many to constantly replace SD ammo, therefore leading to my routine above. I also cannot think of reading where expensive SD ammo caused a kaboom. I can recall reading many times where reloads or target ammo caused a kaboom on the very first time the cartridge was chambered.

So I keep asking myself; Can bullet setback cause catastrophic failure of the handgun, or is that just another gun myth?

BTW, I'm not a believer in conventional wisdom because I think it's a product of institutional inertia and can often be proven wrong.

 

[cosermann]

... I might be wrong but I think most of us probably have a similar routine that I described above. ...

My gut says that this isn't the norm among experienced shooters.

Firearms go into in my secure, yet quickly accessible, storage when not on me/in use. When they're retrieved they get a mag check and press check. That's it.

I maybe load/unload the top round 24 times / yr (simply to demo something, try a new holster, light, before/after a range session, etc.) and rotate out my carry ammo annually.

Set back is purported to be an issue, but with a relatively small number of load/unloads, I haven't seen it myself.

If you're loading/unloading 365 times in a year . . . YMMV.

Some wives apparently should be educated on the risk associated with all these administrative unloads/reloads, and weigh that against the risk of simply locking it up - not to mention the risk of needing a gun NOW, and having nothing but unloaded guns around.

Do you drain the gas out of your car when you park it for the night and refill it every morning? I mean, you know, the kids could swipe your keys and go for a joy ride, run over someone, and wreck the car. Much safer to have in the garage with an empty gas tank.

 

[BravoMike]

My gut says that this isn't the norm among experienced shooters.

Firearms go into in my secure, yet quickly accessible, storage when not on me/in use. When they're retrieved they get a mag check and press check. That's it.

I maybe load/unload the top round 24 times / yr (simply to demo something, try a new holster, light, before/after a range session, etc.) and rotate out my carry ammo annually.

Set back is purported to be an issue, but with a relatively small number of load/unloads, I haven't seen it myself.

If you're loading/unloading 365 times in a year . . . YMMV.

Some wives apparently should be educated on the risk associated with all these administrative unloads/reloads, and weigh that against the risk of simply locking it up - not to mention the risk of needing a gun NOW, and having nothing but unloaded guns around.

Do you drain the gas out of your car when you park it for the night and refill it every morning? I mean, you know, the kids could swipe your keys and go for a joy ride, run over someone, and wreck the car. Much safer to have in the garage with an empty gas tank.

I'm not sure how often I unload/load my gun, but I would say it's more than 24 times in a year. The article earlier showed that on one particular manufacture and model, the bullet would max it's set back by about the 10th round. I realize this can change between manufactures and models of cartridges and guns, but just using that as an example. Also, the graph that was shown earlier shows that after about 0.1", the pressure actually decreases. This graph showed that this happened before the cartridge pressure reached its max structural limitation. Realize that this graph is for a .357 sig, which to my understanding is already a "high pressure" cartridge.

Yes, setback is a purported issue, but is it really an issue? I'm not saying that it isn't, I would just like to educate myself.

 

[eldirector]

Yes, setback is a purported issue, but is it really an issue? I'm not saying that it isn't, I would just like to educate myself.

No first-hand experience, but I've read up a tad. Increased setback (reduced OAL) CAN increase case pressure. Increased case pressure CAN cause the case to fail. A failed case CAN cause a "kaboom". Notice each says "can", and not "will".

Other variables:
- OAL is related to case volume, which is also related to bullet size
- bullets of different design can have the same OAL and different case volumes
- There is a pretty wide range of acceptable pressures for most cartridges.
- So, if the case volume is at the high end, the powder load at the low end, then you can have a LOT of setback before running into pressure issues
- But, if the case volume is at the low end, and the powder load at the high end, it may not take much to reach the threshold.
- Some cartridges have a LOT of wiggle room, mostly because of their case volume. For example, a .45 loaded light with a light bullet could likely handle more "setback" than a 9MM loaded to +P with a heavy round.

Add to this, different guns support the chambered round differently, so over-pressure could be startling (in a 1911, for example) to downright painful (a Glock, for instance). As a matter of fact, the .40 S&W Glocks may be the reason for all of this setback/overpressure discussion. The .40 has a fairly small cartridge volume, is already running at a pretty decent pressure, and the Glock doesn't fully support the cartridge when chambered.

 

[BravoMike]

No first-hand experience, but I've read up a tad. Increased setback (reduced OAL) CAN increase case pressure. Increased case pressure CAN cause the case to fail. A failed case CAN cause a "kaboom". Notice each says "can", and not "will".

Other variables:
- OAL is related to case volume, which is also related to bullet size
- bullets of different design can have the same OAL and different case volumes
- There is a pretty wide range of acceptable pressures for most cartridges.
- So, if the case volume is at the high end, the powder load at the low end, then you can have a LOT of setback before running into pressure issues
- But, if the case volume is at the low end, and the powder load at the high end, it may not take much to reach the threshold.
- Some cartridges have a LOT of wiggle room, mostly because of their case volume. For example, a .45 loaded light with a light bullet could likely handle more "setback" than a 9MM loaded to +P with a heavy round.

Add to this, different guns support the chambered round differently, so over-pressure could be startling (in a 1911, for example) to downright painful (a Glock, for instance). As a matter of fact, the .40 S&W Glocks may be the reason for all of this setback/overpressure discussion. The .40 has a fairly small cartridge volume, is already running at a pretty decent pressure, and the Glock doesn't fully support the cartridge when chambered.

This seems to make logical sense. Does anyone have any examples of this happening solely because of bullet setback?

 

[MooreALX]

I get the part about putting it in the safe but I think it was mentioned already that you are at a much greater risk of an AD whenever you chamber/un-chamber a round then if you were to leave it loaded and secured in a safe.

This is a very good point, something that honestly I didn't think about as I'm always very careful while loading/unloading.

I carry my Glock 17 with 16rds in the magazine, and one in chamber, and have been working out of my box of 20 GoldDots. So I have been cycling the 4 left-overs between the round that I chamber each time. I'm trying to keep the cost of my SD ammo down as much as possible as I'm working on a College student's budget. The more I save on SD ammo, the more target ammo I can afford. That said, there isn't a price on safety, and you can't cut corners. I really liked JettaKnight's method, it seems reasonably affordable, especially if I don't unchamber as often.

if I was in this situation I'd
- have a box that each round would go into when I emptied the chamber.
- In the morning, I'd grab a fresh round from a new box, load it on top of the magazine then rack it into the chamber.
- Repeat until no new rounds in the fresh box.
- Now remove all rounds from the magazine and place in fresh box.
- Reload magazine with used rounds.
- Continue process unitl fresh box is empty again.
- At this point, all rounds have once loading cycle.
- Dump the used rounds in the fresh box and repeat this whole process as many times as you dare.