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Discussion Starter · #1 ·
just wondering. also what about if it's too high?

specifically I'm wondering about the types of malfunctions you have seen and attributed to the gas settings.

thanks
 

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When the gas is too low I have experianced some case expansion which locks up the weapon and requires a lot of force on the charging handle to clear
 

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When the gas is too low I have experianced some case expansion which locks up the weapon and requires a lot of force on the charging handle to clear
Ahh... how would that be a function of the gas setting? I've shot my XCR, FALs, and plenty of bolt guns all with no gas at all, and they extract just fine afterward... I'd wager that the higher gas setting was simply imparting enough energy to exact the case, but that the case is equally "stuck" regardless of the gas setting.
 

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I'm thinking it's an ammo problem.....

I run Winchester white-box M193 through mine for the most part. When I run the new gas system at 1, everything is cool until about 400 rounds - then I start to get intermittent failures to eject.

Extraction is fine, but the round winds up smoke-stacking. That and the bolt doesn't have the umph to lock back after the last round in the mag has been fired.

So I run mine on 2, and haven't found the point where reliability tapers off as of yet.
 

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When my gas setting is too low it will fail to hold open on the last round and sometimes fail to chamber the next round in the mag. When I turn the setting back up the problems with these go away.
 

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I have some silverbear,but Ive not ran much of it thru it yet.How hard,as in hot were you running it at the time,or do you remember? I wonder if that would have anything to do with,combined with the zinc plating.
It was abuse. I went through about 1000 rounds that day alone. On gas setting 3 or 4 I didnt have any issues. On gas setting two though, the cases got stuck in there pretty good.
 

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I ran some Silver Bear in the XCR with no problems (needed gas setting 3 for reliability in a clean gun), but it wasn't being beat on like that.
 

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I have some silverbear,but Ive not ran much of it thru it yet.How hard,as in hot were you running it at the time,or do you remember? I wonder if that would have anything to do with,combined with the zinc plating.
It was abuse. I went through about 1000 rounds that day alone. On gas setting 3 or 4 I didnt have any issues. On gas setting two though, the cases got stuck in there pretty good.
I had the same issue with Silver Bear on setting of 2. After my break in I was going to lower it to 2 and go to town. I pulled on the trigger and didn't notice any recoil and was scared to death I had a live round in the chamber. Dropped the magazine and tried to clear and I couldn't get it out. I had one of the guys are the range break it down for me since I thought the round was live... I was embarassed and left!

Better safe than sorry though!
 

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That stuff shoots pretty dirty kinda like Wolf.I've noticed some types of powder has a sticky residue.Some of that cheapass Indian surplus 7.62x51 is like tar,really nasty stuff.Steel cases,and the heat of firing multiple magazines,combined with fouling,and the mild variances in chamber tolerances might be the problem.I'm not an engineer,I'm just thinking out loud I guess.



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Discussion Starter · #14 ·
So as I am reading it here are the symptoms of too low of a gas setting

-failure to extract
-failure to eject/stovepipe
-failure to lock on empty

is that about it?


NY32182,
I would technically agree that sticking in the chamber would not intuitively seem to be a gas problem, but being a new design and there being other factor in extraction/ejection cycle other than bolt impluse, things like case expansion, or lack there-of, case construction and coatings to name a few.

I wonder if when you have the gas too low, it does not allow for the pressure to drop fast enough, allowing the case to contract, and thus creates case sticking?
 

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The case contracting would cause the opposite of sticking. That is one of the knocks on steel cases; they don't contract as much as brass and therefore lead to harder extraction. The timing of good extraction is such that it should not happen until the chamber pressure had dropped enough to allow the case to contract some. If you have the gas up too high, it could cause the extraction to start early, leading to more stress on the extractor as it pulls out a case that is still expanded hard against the chamber walls. Extreme case of this, and you could rip the rim off a case. This will also happen if the case is stuck hard enough for another reason. I can't think of a way that not enough gas would directly contribute to cases sticking. Cases sticking may *become more evident* through lousy extraction if your gas setting is low, but having the gas low will not be a direct *cause* of the sticking. (I believe that to be correct and hope it makes sense. :))

One simple test to see if your cases are really sticking, would be to just turn the gas all the way off and fire a shot. Pull charging handle. If it is difficult to extract, your cases are sticking.
 

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So as I am reading it here are the symptoms of too low of a gas setting

-failure to extract
-failure to eject/stovepipe
-failure to lock on empty

is that about it?
To the extreme I am seeing failure to eject/stovepipe. Usually I see the brass kinda "fall" out of the ejection port and land right next to me, with the Failure to lock back after the last round.

I have seen the same as Bravo with it starting to act up every 300-400 rounds or so. It will run fine for a while then it almost looks like it is short stroking a bit. turn the gas up one and all is fine.
 
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Discussion Starter · #17 ·
The case contracting would cause the opposite of sticking. That is one of the knocks on steel cases; they don't contract as much as brass and therefore lead to harder extraction. The timing of good extraction is such that it should not happen until the chamber pressure had dropped enough to allow the case to contract some. If you have the gas up too high, it could cause the extraction to start early, leading to more stress on the extractor as it pulls out a case that is still expanded hard against the chamber walls. Extreme case of this, and you could rip the rim off a case. This will also happen if the case is stuck hard enough for another reason. I can't think of a way that not enough gas would directly contribute to cases sticking. Cases sticking may *become more evident* through lousy extraction if your gas setting is low, but having the gas low will not be a direct *cause* of the sticking. (I believe that to be correct and hope it makes sense. :))

One simple test to see if your cases are really sticking, would be to just turn the gas all the way off and fire a shot. Pull charging handle. If it is difficult to extract, your cases are sticking.
See thats what I would think would happen from my basic knowledge of how shit works!!, BUUUT, knowing that the timing is as important as the amount of gas, I think that the opposite is actually happening.

the round goes boom, bullet travels past gas bleed, and starts to fill piston, bullet leaves barrel and pressure drops. (heres where it gets tricky) since there was not enough gas bled off into the piston, there is still too much pressure on the cases which would in turn mean that the timing was basically not right in the whole system. There is still enough gas to extract and cycle the action, and even rip the case rim off, but the timing of the contraction of the case is too slow and thus it sticks.

If the gas were higher then more gas could be sent into the piston and thus allow pressure drop a millisecond or so faster and let that case contract enough for reliable extraction. In reality, the piston aint gonna move any sooner with more gas, and the bullet is long out of the barrel before it does start to move, but it will move with more authority and have more gas acting on it.

If you add other mitigating factors like polymer case coatings, differences from round to round and crud build-up, then you start to get a better picture of the whole situation.

Now, I dont know if this is actually the case, but it would seem to explain why it's doing what it's doing.

your method of testing may show some result. but with the sticking only a sporadic thing, it may be many shots before you got a result.
 

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I think there are a couple of problems with that theory. First, I don't think the gas system uses a large enough percentage of the gas traveling down the barrel to affect the degree of expansion of the case, on any gas setting. Second, once the bullet has left the barrel, the only thing contributing to the friction between the case and the chamber are the dimensions of the case after expansion and contraction, and the materials that the case and any external coatings are made of. If my understanding is correct, all autoloaders are designed to perform extraction after the bullet has left the chamber and the pressure has dropped, to insure safety and to insure that the bullet reaches the maximum possible velocity before leaving the barrel. As has already been pointed out, lower pressure would result in late (and weak) exraction. I would think that a design that relied on a minimum residual chamber pressure to insure reliable extraction would be extremely tricky to time correctly, and would be very sensitive to the ammunition being fired!
 

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Well Jack to put it simple..... Low no go extraction, High....... way in the woods. Suggestion.... read manual and adjust accordingly.
 
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