Re-chambering vs direct chambering update 3...

I'm not understanding how it is simpler to keep up with how many times all rounds have been chambered from the mag, simpler to rotate rounds, and simpler to watch for bullet reset than not having to bother with any of that at all by simply directly loading the chamber in guns that allow it.

And, actually there are problems with loading from the mag. Why would Sig not honor their own warranty if they discover a round has been chambered more than once from the mag?

I always chambered from the mag until I noticed two rounds with setback in my M&P mag. That's what got me noticing the whole setback problem.

I'm not sure I've ever seen it mentioned but why not "ride the slide" when chambering a round from the mag instead of releasing from slide lock or "sling shoting" the slide? I've done this with my 1911, XD and M&P with no problem. The slide strips the round, the case rim slides under the extractor and the round chambers--gently. No ramming the bullet nose into the feed ramp, therefore, no setback.

I did test my 45 cast bullet reloads for setback and it generally takes about 4-5 cycles to start setback. I reduced the diameter of my expander plug so the case would have a better grip on the bullet to help prevent setback.

Cloudpeak

bacchus - It should not be possible to slam fire in any properly designed gun. The firing pin is not going to move...its locked and under spring tension.

In the normal cycle of operations, the rim of the case slides up underneath the lip of the extractor from the magazine. If you put the round directly in the chamber it makes sense your point of impact will be different, because as the extractor smashes into the case (all pressure on one side of the round) and then manages to flex enough to pop around the extractor groove allowing the slide to go all the way into battery you're going to be abusing that round quite a bit more than you normally would - instead of being pushed in straight with equal pressure from the entire breechface, you're getting a major side load (and potentially hurting your extractor in some guns).

I have a Sig, and I'm not going to do it. I definitely would not load with this method on something with an internal extractor (1911). Thats just me though...and my $0.02

Austin

edited to add: I was taught this is called the "Bubba Load" - implication being something a person of lower than average intelligence would do. I don't know anyone named Bubba, and I don't want to paint anyone with that brush - its just what I was taught. If a manufacturer says its ok, good for them...just not good for me. Mechanically it doesn't make sense, and I don't see the benefits outweighing the downsides. JMO

I do a random rotation by removing 3-5 rounds, mixing them up, and replacing. I have 3 magazines loaded with SD ammo and usually shoot the chambered round fairly often when practicing.

Quote:

---

Originally Posted by aus71383

...If you put the round directly in the chamber it makes sense your point of impact will be different...

---

Have you actually tested that or know of anyone that has?

Hmmm, after reading that it seemed a bit blunt. I did not mean it like that at all. I'm just curious if anyone has tested this and seen a measureable difference.

Quote:

---

Originally Posted by aus71383

...because as the extractor smashes into the case (all pressure on one side of the round) and then manages to flex enough to pop around the extractor groove allowing the slide to go all the way into battery you're going to be abusing that round quite a bit more than you normally would - instead of being pushed in straight with equal pressure from the entire breechface, you're getting a major side load (and potentially hurting your extractor in some guns)....

---

Have you ever seen a slow motion video of a round being chambered from the magazine? It is violent.

The round is started in motion by a hard impact from the slide directly to the top edge of the case. IMO, far more forcefully than an extractor riding over the edge of the case.

Because the round is under spring pressure, the case is forced firmly into the magazine's lips so the round has to be torn free of the magazine. The first thing that happens to the round, is the bullet makes high speed contact with the feed ramp. The bullet often deflects off the feed ramp into the top of the chamber and is then rattled into and seated in the chamber.

Compare that to the action of direct chambering. The round experiences no stripping from the magazine, no bouncing off the feed ramp, no bouncing off the top of the chamber. By the time the extractor contacts the case, the case is pretty much fully supported in the chamber. The extractor is a spring itself or spring loaded and simply lifts over the rim of the case and it's all over.

BTW, what happens when one clears a double feed, i.e. failure to extract a fired case? You remove the mag, rack the slide several times and guess what that does? It forces the extractor over the rim of the case. If we practice that, and an extractor is sensitive to direct chamber loading, you may want to stop practicing double feed drills.

There may be other guns, but currently the only ones we know for sure that approve of direct chamber loading is Sig, Ruger, and Beretta. H&K approves of direct chamber loading if you do it gently and press on the back of the external extractor to raise the extractor over the rim.

Quote:

---

I'm not understanding how it is simpler to keep up with how many times all rounds have been chambered from the mag, simpler to rotate rounds, and simpler to watch for bullet reset than not having to bother with any of that at all by simply directly loading the chamber in guns that allow it.

---

Different strokes for different folks. If you had as many different autos like I do you would understand that it would be a real pain to remember which gun it is allowed and which it isn't. I don't have a problem with set back as I very seldom unload my weapon and when I do the SD rounds are usually shot and the gun cleaned and replaced with fresh ammo. I suppose if you keep your SD ammo for years and unload daily you might have issues, but as I said for me it is easier to simply continue as always.
Good Day.
NCH

I probably do have as many different autos as you, and I simply remember if it's not a Sig, Beretta, Ruger, or H&K, don't direct chamber it. That's a whole lot simpler than keeping up with the rounds.

You do make a good point though. If you don't have to unload/reload much then it's not as much of an issue. I do have to unload and reload sometimes more than once a day, so it's more important to me to not have to worry about the number of times the rounds in three mags have been chambered from the mag.

Tangle - no, I haven't tested it. I know loading is violent, but its consistent. Do you see what I mean about the extractor hitting the case rim with all the force of the slide moving forward under spring tension?

The only time my guns are unloaded is when I'm cleaning them or practicing drawing - I measure my ammo for setback before loading back up. Plus maybe I'm just biased and don't want to be a "Bubba". :wink:

Austin

Quote:

---

Originally Posted by Tangle

Every time the round is forced out of the magazine, under the full force of the mag spring, the mag lips score the round and possibly score the bullet itself.

---

That is interesting. Maybe you need your magazines tuned? You might want to have the burrs on the lips removed, and the lips measured, so the lips hold the rounds without scoring them.


Later,
M

A better word would have been scratch. And, not all mags scratch cases. More to the point, scratching is very minor, but stripping a round from a magazine is not necessarily a harmless thing, especially when considering doing it multiple times on the rounds.

For example, if you take an M&P and slowly lower the slide, the round will actually hang on the feed ramp so severely that it will hold the slide open. Remember in a previous post I stated that I first became aware of setback when I found two rounds in my M&P mag with noticeable setback. I thought I was randomly rotating the top three or four rounds, but I still got the setback.

After polishing both the feed ramp and the mag lips, and adjusting them a bit, I was able to all but eliminate the hanging. But the point is loading a round from the mag is not a gentle thing, and while we talk about that's the way guns are designed, we haven't mentioned that rounds are not designed to be chambered numerous times.

Quote:

---

Originally Posted by aus71383

Tangle - no, I haven't tested it. I know loading is violent, but its consistent. Do you see what I mean about the extractor hitting the case rim with all the force of the slide moving forward under spring tension?

---

The slide hits the top edge of the case under full force when it strips it from the mag. At the point where the mag makes first contact with the round, the recoil spring is just about fully compressed and the slide strikes the round, on the top edge, with full force.

If there is no round in the chamber, a slide will still hit with full force. Hence it is not the round that is absorbing the force of the slide. The only force the case gets, is a bit of pressure from the extractor slipping over the rim.

But if it hasn't been tested, we don't know if it changes the point of impact or not. I can do this. I'm expecting a Sig 220R Carry SAO to come in tomorrow and I'll have time to shoot it. I'll load ten rounds using direct chambering and follow each round with four rounds that get loaded by the gun's firing cycle and see if I can see any difference.

Usually what I get is 5 shots in one hole. So if I see a first shot shift we may want to do some further testing to see if the POI change is repeatable.

To be honest, I don't think I'll see a bit of difference.

Quote:

---

Originally Posted by aus71383

The only time my guns are unloaded is when I'm cleaning them or practicing drawing - I measure my ammo for setback before loading back up. Plus maybe I'm just biased and don't want to be a "Bubba". :wink:

Austin

---

I doubt many people measure their ammo for setback and I doubt they ever will. I don't and don't want to measure some 50 SD rounds for setback. So when I find a way to avoid the issue entirely, with the manufacturer's blessing, I see no reason not to use it.

The bottom line is, that setback is real. If you chamber rounds from the mag repeatedly, you will get setback. Setback can raise chamber pressures and even if it doesn't damage the gun, it will change the POI far more than an extractor slipping over the edge of a case.

Most of us will not measure rounds for setback. First, we'd have to have a caliper to measure with. I doubt many of us have that. Even if we did, we'd have to have known data from each manufactuer to compare the rounds to. It is not enough to measure each round just to see if they are the same - all the rounds could be wrong. So we have to work from the manufacturer specs.

I'm still having a difficult time seeing how rotating rounds, measuring for setback, etc. is simpler than avoiding the problem altogether. Maybe Bubba knows something after all.

This has come up several times during the short time I've been a
forum member. Everyone should get a micrometer {cheap or expensive } and keep track of the rnd reloaded. As stated, some guns and gentile chambering and one may not get set back.
My problem has been the reverse, I've had pistol cartridges get longer in the unfired rnds when used in revolvers.

I don't see a round getting hit by the slide as its getting stripped out of the magazine as "full force". The slide just started moving - it was all the way back. Then when it does hit the round, the round slides forward. It bangs around a bit, and slides up underneath the extractor, and the slide continues into battery.

Just about every automatic (excepting bottlenecks) headspaces off the case mouth - so picture the opposite scenario. The round is dropped into the chamber. At this point, the round is fully chambered. The slide is all the way back, you as it drops forward under spring tension it gains speed and momentum until "Wham!" the extractor (and only the extractor) makes contact with the chambered round. This has got to smash the case mouth something awful inside the chamber - I imagine it will cant it to one side slightly due to being hit only in one small place by the extractor.

It just seems wrong to me. On my AR-15 I would not hesitate to load this way - it happens every time anyhow because that's how its designed. But then again that's a bottlenecked cartridge that headspaces off the shoulder, so it shouldn't be effected near as much as something rimless that's headspacing off the mouth.

I'm not a scientist or an engineer, this is just my understanding of the mechanics of what goes on during the normal cycle of operations. I know for a fact that my autoloaders (Sig included) are designed to have the cartridge slide up the breech face underneath the extractor.

Austin

Another FYI. On my Colts the extractors are all high quality and properly tensioned, configured and tuned.

It is not necessary for me to slam the 1911 slide
'full force' forward to direct chamber a cartridge.

I just checked this with 3 of my Colts and I can drop a round into the chamber then slowly ease the slide fully forward until the extractor rests on the rear of the chambered cartridge case...then pull the slide back approximately 1.5" then release - and the extractor will easily pop over the case without even leaving a mark on it.

Austin,
You are exactly right, it is no where near the same. It is basic principles of momentum of motion. As I said before different strokes for different folks. We all use our guns in different ways, some reload often and others seldom, this is a huge factor here. Some of us reload and understand setback, or the lack thereof and know how to check for it, as well as having the proper tools, others don't. Bottom line load your weapon the way you want to and when it fails you have nobody else to blame but yourself. If it never fails then you can shake your own hand and pat yourself on your back. This subject is getting to be a dead horse and being beat hard!!

NCH