Posted: 10/22/2011 4:42:00 PM EDT
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So I've read that chambering a round more than once or twice may cause bullet setback which is a no no.
my question was does this come from the bullet coming out of the mag and hitting the ramp with the force of the slide/bolt behind it? I was curious if you could avoid that problem by simply locking the slide back and manually putting one in the pipe....? lets say it's your HD gun and you take it out for a little cleaning/lubing and when your done you want to load it back up.....well rather than having to always keep which bullet has been chambered set aside and do that whole rotation headache could you just load the mag up and then put one in the chamber manually to avoid the setback? |
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Yes, setback happens due to the bullet striking the ramp while the bolt propels it forward.
Single loading a round directly into the chamber is usually pretty hard on the extractor and can lead to premature extractor breakage. It usually takes several rechamberings of the same round before setback starts to occur, if it occurs at all. Myself, I choose to take it easy on the extractor and always load from the magazine. I have yet to see any setback problems, be it with pistol ammo (such as .40 S&W) or rifle (such as 5.56 NATO). If I have any doubt about a particular round, I'll toss that one round. I figure that's preferable to possibly breaking the extractor. I replace my carry ammo yearly. |
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If you manually lock the slide back then feed a round into the chamber and then let the slide close, you're forcing the extractor to jump over the rim or the cartridge, this puts extra strain on the extractor. It's not a good thing to do, IMHO. ETA damn I type too slowly. |
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Quoted:
this came up over at LF recently and it was shown that even after chambering as few as 2 times, setback can occur even with crimped rounds I suppose so, but I have yet to see it happen with properly-crimped cannelured bullets. I'm not saying it doesn't happen, but I just haven't personally seen it.... yet. |
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Quoted:
ah I wasn't aware it was bad for the extractor. is this on all guns? internal and external extractors? I'm glad I asked before I did it. I understand that some bolt action rifles (the info I found talked about Mausers, Winchester 70s, and the Ruger 77) can have their extractors beveled and polished to work well with single loading. However, unless the chamber is also relieved to allow extra room for the extractor to snap over the rim, the chamber can become worn at that point. It's just a helluva lot easier (and cheaper) to just load from a magazine and to toss any hinky-looking rounds (if you ever even see one). |
| I've heard it's an issue with .357 SIG (left uncrimpred, although I don't know why... Something to do with the headspacing at the mouth rather than at the shoulder), but not with normal handgun ammo, or even rifle ammo (which is properly headspaced at shoulder and the case is crimped) |
