Chambering .45 ACP multiple times...problem?

[aeriedad]

Here and in other forums I've seen folks recommend against chambering a round multiple times since it can cause it to recess into the cartridge and possibly result in over-pressure, under-pressure or something else bad. While I don't have an abundance of experience carrying, I've never noticed such an effect. Retired from the Marine Corps a few years ago, and pretty much every round I ever chambered was fired relatively soon afterward, so I never heard of this issue before.

Earlier this year I began carrying a 1911 and shooting 50-100 rounds of WWB almost every week. Defensive ammo is Winchester PDX1. So at least once a week I drop the magazine, eject the round and replace at the top of the magazine. (I don't do +1, mostly so I don't have to find another place for the extra round when unloading for practice.) I have two other magazines I use for practice. After about 300 rounds or so of WWB, I fired a whole magazine of PDX1, no problems at all. About every 4 - 6 weeks I fire off the first two rounds of my defensive magazine, mostly to make sure everything works, but also because I want to keep a fresh round in the chamber. If I remove the defensive rounds for some reason, I keep them in sequence so the frequently chambered round is always the next to re-chamber and be fired.

Now, the question: What experiences can other shooters share in this regard? Not really looking for what others may have heard or read elsewhere (unless it's particularly interesting), but what can you tell me from first-hand experience?

My defensive ammo has fired every time so far, so I don't see the need to change my practice. But since my life may one day depend on the round in the chamber, I would give weight to advice based on experience (as opposed to hearsay). Thanks,

 

[mgmorden]

It takes quite a few times for it to make a difference, but over time it can create a pressure spike.

If you can deal with record keeping, try limit yourself to 5 or so chamberings of the round before retiring it.

If you don't want to deal with the records, just drop your mag before practice, put in your practice mag and just shoot that one SD round as part of your regime. Top the mag back off before you carry again.

Even with SD ammo if you did this once per week you'd only be spending an extra $50/year for the peace of mind, which is pretty miniscule compared to your overall yearly ammo bill if you're shooting a box or two of WWB every week.

Oh yeah - good to see someone from Moncks Corner on here! I actually work in MC.

 

[FIVETWOSEVEN]

.40 S&W hates being rechambered too many times, I did a test. .40 S&W got set back about 3-4mm. 9mm Stood up to chambering over 50 times without an issue. I haven't tested .45 ACP yet. Best way to test is take a single FMJ round and rechamber it till you get bored. If it doesn't get set back than your fine.

With my .40, it gets unchambered alot and I rechamber the same round alot, what I do is I drop the round in the chamber, let to slide go gently till the extractor is against the rim. I then tilt the pistol back and pull the slide back until the round drops out of the chamber slightly and the rim is behind the extractor. Then I let it go forward gently.

 

[Drail]

The reason a round sets back has nothing to do with caliber. It has everything to do with poor quality control by the maker. That said anyone who feels that they "need" to unchamber and rechamber ammo repeatedly needs to find a way to stop doing that. The factories are NOT manufacturing ammo that will withstand repeated rechambering. They could and they should but they do not care. They do not believe that their customers need that ability. If you want ammo that won't set back you have to load it yourself. The ammo factories are designing and building to a price point with sales of X number of units. They only have to sell the stuff. It doesn't have to work reliably. It only has to sell. If you want high quality ammo learn to reload.

 

[rcmodel]

How many rounds do you suppose get set back on the first chambering?
And fired without any adverse effects!

Pressure testing and liability laws being what they are today?
I do not believe any factory ammo is going to blow off your hand if the bullet does get set back.

If there is really a concern, just mark every new round with a black line around the bullet/case joint with a Sharpie pen.

When the black line disappears inside the case, shoot it for practice ammo.

rc

 

[Steve C]

I've found that some ammo will exhibit quite a bit of set back after one or two chamberings while others have not noticeable OAL reduction after many rechamberngs. IMO this has more to do with the bullet shape and how much it impacts the feed ramp which varies by handgun make and sometimes particular magazine and how much crimp or bullet hold the ammo has.

I have had more excessive set back issues with factory Speer Gold Dots than any other brand of ammo and the least issues with ammo loaded by Winchester and Federal.

 

[Zerodefect]

It takes quite a few times for it to make a difference, but over time it can create a pressure spike.

If you can deal with record keeping, try limit yourself to 5 or so chamberings of the round before retiring it.

If you don't want to deal with the records, just drop your mag before practice, put in your practice mag and just shoot that one SD round as part of your regime. Top the mag back off before you carry again.

Even with SD ammo if you did this once per week you'd only be spending an extra $50/year for the peace of mind, which is pretty miniscule compared to your overall yearly ammo bill if you're shooting a box or two of WWB every week.

Oh yeah - good to see someone from Moncks Corner on here! I actually work in MC.

This is what I do as well. I shoot the one in the pipe. Sometimes I shoot all the ammo in my mag.

If I carry the same pistol for a month. In rain, snow, salty snow, salty sea, flying sand, bugs, pocket lint, oil, engine antifreeze, concrete dust........that ammo starts to look really nasty. Green rusty jackets etc.

The only way to know if that ammo still works is to shoot it. So far no problems, but I don't hang on to carry ammo too long.

 

[The Lone Haranguer]

I see little reason to unchamber and rechamber any round multiple times. Unless you intend to clean or dryfire (for practice) the gun, why bother? But the .45 Auto, with its low(er) operating pressures and generous case capacity, is extremely unlikely to blow up a set-back round. Whether it would feed properly from the magazine is another question.

 

[Manco]

Here and in other forums I've seen folks recommend against chambering a round multiple times since it can cause it to recess into the cartridge and possibly result in over-pressure, under-pressure or something else bad.

The concern is about overpressure, since a setback bullet reduces the interior volume of the case where the powder is, and powder burning in a more tightly-enclosed space can create higher pressure at a faster rate.

Now, the question: What experiences can other shooters share in this regard? Not really looking for what others may have heard or read elsewhere (unless it's particularly interesting), but what can you tell me from first-hand experience?

I've always taken potential bullet setback issues into consideration, so I've never experienced an instance myself. However, I can tell you through testing that the PDX1 (.40 S&W in my case) can stand up to a LOT of chambering. That's probably because the bullet fits really tightly and is cemented in there hard with tar. I stopped after 30 or so chamberings with the same cartridge, and couldn't detect any bullet setback. I haven't tested any other ammo, but in previous threads on this topic, forum members have reported instances of setback. Speer Gold Dot (excellent personal defense and LE ammo--I'm NOT trying to knock it), for example, has a warning on the box related to repeated chambering, and somebody here did manage to detect some bullet setback on one such cartridge after several chamberings. From what I've seen regarding cartridge construction, I would guess that most bulk/range ammo is similarly susceptible.

To be safe, I generally treat all cartridges as susceptible to bullet setback, which means that already-chambered cartridges get chucked onto the range pile, where they will only get chambered one more time at the most.

My defensive ammo has fired every time so far, so I don't see the need to change my practice. But since my life may one day depend on the round in the chamber, I would give weight to advice based on experience (as opposed to hearsay). Thanks,

Some can take a lot of chambering, while others cannot. .45 ACP is fairly forgiving of bullet setback, and PDX1 construction is quite resistant to it as well, so you probably don't have anything to worry about whatsoever, but it's still good to be aware of such an issue. If you try not to chamber rounds unnecessarily (especially range ammo), and shoot some of your defensive ammo off every so often (like you already do), then it should be a non-issue for you. The same is not true for everybody, however.

.40 S&W hates being rechambered too many times, I did a test. .40 S&W got set back about 3-4mm. 9mm Stood up to chambering over 50 times without an issue.

It depends on the design of the cartridge as a whole (and can potentially vary among individual cartridges), not so much on the caliber. Where the latter is involved is how much of a surface there is for the case to grip the bullet, and 9mm with its tapered case is definitely not inherently better than .40 S&W in this regard. Things like the fit of the bullet, any cements used, and taper crimping, for example, are more significant.

The reason that .40 S&W is so often singled out concerning the issue of bullet setback is that it is inherently less forgiving than most calibers when a bullet does get set back, not that it is more prone to this happening in the first place. A setback bullet may or may not cause your gun to explode, but the latter is more likely to happen with .40 S&W than with .45 ACP. That said, if you don't let your bullets get set back, then caliber is moot.

How many rounds do you suppose get set back on the first chambering?
And fired without any adverse effects!

I would say that not many get set back measurably on the first chambering (unless the ammo is of such low quality as to be unsafe), and even the few that do aren't set back enough to be an issue--it's repeated chambering and the significant amounts of setback that can potentially result that are dangerous.

Pressure testing and liability laws being what they are today?
I do not believe any factory ammo is going to blow off your hand if the bullet does get set back.

If you set any bullet back far enough (in the common autoloader calibers) and the round uses a sufficiently fast powder (as most do), then it will cause an explosion according to the laws of physics. This is not going to happen with a single chambering of factory ammo unless the cartridge in question is defective, but under certain circumstances it could happen.

 

[FIVETWOSEVEN]

The reason a round sets back has nothing to do with caliber. It has everything to do with poor quality control by the maker. That said anyone who feels that they "need" to unchamber and rechamber ammo repeatedly needs to find a way to stop doing that.

Can't dry fire a loaded gun. If I had a camera I would show a round of .40 S&W loaded about 50 times and a round of 9mm loaded 50 times. 9mm just has some scuff marks while the .40 S&W is set back a considerable amount.

 

[aeriedad]

mgmorden, I wish I could shoot a box or two of WWB every week. Usually I only get to shoot 30-40 rounds. One or two of my sons get 25-30 rounds (each), and sometimes my wife shoots 10-15. It does get expensive. We do buy the 100-round boxes from Wal-Mart though, which is better than we can find online (counting shipping costs). It's funny you live in Charleston and work in MC. Mostly I work in North Charleston, but also have an office in Charleston that I see once or twice a month.

Drail, thanks for not sharing one word of personal experience. Unless you've ever worked in quality control at one or more ammo manufacturers, I'm assuming your reply is hearsay and opinion based on hearsay. I can tend to my own needs, so if that's all you've got to say, please keep it to yourself.

Lone Haranguer, I do clean every week after firing. I've gone two weeks between range visits only a couple times in 7-8 months, but if it were to be more than a month or so, I would probably clean again at least once. We only have my 1911 and my wife's S&W M&P9 right now, but Saturday we're getting her a S&W 642 for carry. Gun cleaning is the man's job at my house. Anyway, like I said, haven't had a problem with any of my SD rounds feeding and firing yet.

Manco...Excellent reply! I've browsed THR casually for a couple of years, but it's because of folks like you that I eventually joined just a couple weeks ago. Thank you!

 

[jbm0207]

I always thought the MAIN issue of limiting how much you chamber and rechamber the same round had to do with the impact the extractor has on the geometry of the rim around the case. The potential problem being that doing so could cause such a change in geometry that effective extraction could be compromised.

I understand the pressure issue too. And believe it is also a concern but always thought the main issue was about extraction.

I also understand bullet setback, but I have always thought between extraction, over-pressure, and bullet setback...bullet setback would be the least likely. ?

 

[Safetychain]

I don't really understand this pressure spike thing. My several load manuals appear to have several listings for compressed loads. Doesn't this mean the bullet is actually seated to the point of pressing down on the powder? Obviously there is no worry about explosion problems in these loads. What is the difference? Fast vs slow powders?

 

[mgmorden]

I don't really understand this pressure spike thing. My several load manuals appear to have several listings for compressed loads. Doesn't this mean the bullet is actually seated to the point of pressing down on the powder? Obviously there is no worry about explosion problems in these loads. What is the difference? Fast vs slow powders?

Pretty much. Load manuals that show a compressed load are usually doing so because the powder is slow enough that it takes enough that it fills the capacity of the case and still doesn't spike. That load is tailored to that case volume though. If you seat the bullet further down you'll get higher pressures whether the load is compressed or not as you've reduced the available case volume.

 

[Azul]

If it works with your handgun, you could ease the slide forward to chamber your round. No need to worry about setback then. I do this with my XD.

 

[viper7342]

I have experienced bullet setback with my Winchester 127 Grain +P+ Ranger T defense loads in 9 millimeter, but only after many chamberings, granted with A +P+ charge, an overpressure event could and most likely would create major problems, that's the reason anytime I unchamber a round I visually check for setback by holding the round that came out of the chamber next to an identical loaded round from the same box.

 

[Manco]

Can't dry fire a loaded gun. If I had a camera I would show a round of .40 S&W loaded about 50 times and a round of 9mm loaded 50 times. 9mm just has some scuff marks while the .40 S&W is set back a considerable amount.

That's just one example--I'm not doubting your observation but rather your generalization with regard to caliber. There are some .40 S&W cartridges that can take a whole heap of repeat chambering without any ill effects, and others that start to show bullet setback after only three or four chamberings. The same goes for 9mm, I'm sure. Caliber may have some influence, but it's mostly determined by other factors, such as cartridge construction and pistol design. In addition, I see no reason to believe that .40 S&W is particularly susceptible to bullet setback--overpressure due to setback, yes, but not setback per se.

I always thought the MAIN issue of limiting how much you chamber and rechamber the same round had to do with the impact the extractor has on the geometry of the rim around the case. The potential problem being that doing so could cause such a change in geometry that effective extraction could be compromised.

That's another limiting factor, but since setback can start to occur as early as the first chambering--in rare cases, but it's not uncommon after three--and can potentially cause catastrophic damage to both the weapon and shooter, it is considered by some to be more serious, as well as potentially more limiting. When it doesn't happen, then the extractor tearing up the rim can become the main limiting factor, but when it does happen it's a big concern.

I also understand bullet setback, but I have always thought between extraction, over-pressure, and bullet setback...bullet setback would be the least likely. ?

It's difficult to fully characterize, as bullet setback doesn't always happen and doesn't always cause problems even when it does happen. However, the question is not only about likelihood but the severity of the worst-case scenario. Personally, if I saw the rim getting chewed up, I'd be concerned, but not as concerned as if I saw the bullet getting pushed further into the case.

I don't really understand this pressure spike thing. My several load manuals appear to have several listings for compressed loads. Doesn't this mean the bullet is actually seated to the point of pressing down on the powder? Obviously there is no worry about explosion problems in these loads. What is the difference? Fast vs slow powders?

Yes, yes, and yes. Also, it seems that most powders used in factory ammo for autoloaders is fast (less powder needed), although I wouldn't be surprised if it varied over time.

If it works with your handgun, you could ease the slide forward to chamber your round. No need to worry about setback then. I do this with my XD.

Admittedly I've done this with my M&P occasionally (whenever I decide that I need frequent dry-fire practice), and it works fine (I always inspect the cartridge).

 

[FIVETWOSEVEN]

That's just one example--I'm not doubting your observation but rather your generalization with regard to caliber. There are some .40 S&W cartridges that can take a whole heap of repeat chambering without any ill effects, and others that start to show bullet setback after only three or four chamberings. The same goes for 9mm, I'm sure. Caliber may have some influence, but it's mostly determined by other factors, such as cartridge construction and pistol design. In addition, I see no reason to believe that .40 S&W is particularly susceptible to bullet setback--overpressure due to setback, yes, but not setback per se.

Both rounds were Winchester White box, one was 9mm and one was .40 S&W. This isn't a myth or anything, its a real fact that bullet setback exsists and certain calibers are easily affected by this.

 

[mgmorden]

If it works with your handgun, you could ease the slide forward to chamber your round. No need to worry about setback then. I do this with my XD.

The OP mentioned that he was carrying a 1911. Unless it's one of those new-fanangled external extractor models, then this won't work.

 

[Azul]

The OP mentioned that he was carrying a 1911. Unless it's one of those new-fanangled external extractor models, then this won't work.

An XD has an internal extractor as well. It can be done. Just have to ease the slide forward fast enough that the rim of the case gets under extractor properly but slow enough that the bullet doesn't slam the feedramp.

Though my experience is with the XD alone. I don't have a 1911.

 

[mgmorden]

With a 1911, it'll damage it - the extractor isn't made to pivot outwards. It might work a couple times, but you're likely to break the extractor in very short order. Much like a controlled round-feed rifle, 1911's are designed to have the round slip up from underneath.

 

[dhodgins]

You're making this more complicated than it needs to be. Shoot rounds that have been chambered more than a couple of times. You'll go through several boxes of expensive hollow points every year, but so what? You should be rotating your carry ammo anyway.

Generally speaking, I don't worry about overpressure from setback. The .45 is remarkably forgiving. I would be more worried about setting back a bullet far enough that it causes a FTF. 1911s are notoriously picky when it comes to overall length. Obviously that won't happen with the one that's already in the pipe, but if you're moving those multi-chambered rounds down the mag, then yeah, it could be a problem.

 

[FIVETWOSEVEN]

With a 1911, it'll damage it - the extractor isn't made to pivot outwards. It might work a couple times, but you're likely to break the extractor in very short order. Much like a controlled round-feed rifle, 1911's are designed to have the round slip up from underneath.

If you read what he said, it doesn't damage anything. He rides the slide slowly and he chambers a round FROM THE MAGAZINE!

 

[aeriedad]

You're making this more complicated than it needs to be. Shoot rounds that have been chambered more than a couple of times. You'll go through several boxes of expensive hollow points every year, but so what? You should be rotating your carry ammo anyway.

Generally speaking, I don't worry about overpressure from setback. The .45 is remarkably forgiving. I would be more worried about setting back a bullet far enough that it causes a FTF. 1911s are notoriously picky when it comes to overall length. Obviously that won't happen with the one that's already in the pipe, but if you're moving those multi-chambered rounds down the mag, then yeah, it could be a problem.

Not that I keep close track of it, but I figure some of my SD rounds are chambered 5 - 6 times before I fire them, on occasion maybe one or two times more than that. In any case I never allow a multi-chambered round to rotate down the mag, but when I top-off after firing two SD rounds every month or so, I unload the mag and put the fresh rounds at the bottom so they actually rotate up the mag. I shoot regularly enough that keeping careful records seems unnecessary. When it's been long enough, I fire off the first two rounds from the SD mag. I didn't mention it before, but I also inspect the previously chambered round before reloading my SD mag and have never noticed any set-back.

I'm really more interested what people can tell me of their first-hand experience with this issue, particularly involving a 1911 and the same ammo. So far only Manco has provided very useful information based on first-hand experience relative to my question, though a few others have shared some interesting comments as well. This is fine with me since it may or may not be useful to others.

 

[ChCx2744]

We have to understand that bullet set-back is a very real and dangerous thing that happens. Now if you re-chamber the same round a few times, it really shouldn't be an issue, but if you are constantly racking the same round into the chamber multiple times, it can cause problems, especially in loads that are +P, +P+ or higher pressures. I think bullet set-back has had several recorded KBs in some of the higher calibers like .40S&W and .45ACP. I haven't really heard about bullet set-back related KBs in 9mm, but I do believe bullet set-back is something we should all be cautious about. Just rotate your chambered rounds every now and then (I rotate out the chambered round to the end of the line in my box of carry rounds every couple weeks) and use those rounds last, as they cycle through. I've done this for the past couple of years and I haven't had to change my carry ammo for at least a year before buying new. That being said, it's still a good idea to periodically shoot and train with the same type of ammo that you carry, to get used to the feel and perceived recoil difference from practice ammo.