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Chambering problem


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Little bit of background on my S12, new here

 

19"

Bought new about a month ago

Did the trigger forward conversion with the CSS package

Purchased a 10rnd surefire mag and have 2 factory 5s

Bought the MD arms lowbrass puck and the low power recoil spring from CSS

I have polished all the bolt contact points and rails, hammer face, parts of carrier etc

I have carefully filed and polished in a feed ramp (they used to get stuck there, 1 in 15 or so)

 

Everytime I have taken the gun out is has gotten better and better. It started out ONLY cycling buckshot/magnums, FTE on every lowbrass and heavy field high brass even.

 

Today I thought I had FINALLY got all the issues out to reliably use all lowbrass. I was even hip shooting it and letting it recoil on its on as much as possible and it still didnt FTE.

 

Towards the end of my trip, about 125 rounds in I started getting chambering problems. Never seen this one before. I don't know if it could just be too dirty after 100 to work well? That seems unlikely. Here are some re-creation pictures of the problem. The bolt would be quite tight in the position, sometimes couldnt wack the bolt forward and was very difficult to pull the bolt back to free it. 1/2 the time i could slam the bolt forward though. But like I said the other 1/2 it was really stuck. If that wasn't the case Id blame the low power recoil spring. Notice the bottom extractor looking thing on the bolt - the shell is not properly positioned in that (seen in pic 2) Also, I was shouldering/proper stance shooting when this happened, not playing with limp/waist shooting.

 

I had 1 other problem when I was out, that is the 3rd pic. I believe I read that this happens due to the magazine not keeping up with the cycle rate? I was rapid firing out of my 10rnd surefire, it happened while trying to chamber the 9th shot. The live shell is at a high upward angle.

 

The other thing is after 100-125 I started shooting federal, I can't imagine how that could be the problem though...The 3rd pic re-creation - I wasn't shooting federal when that happened.

 

Any thoughts/prayers would be greatly appreciated! Thanks

 

th_IMG_0217.jpg

th_IMG_0220.jpg

th_IMG_0221.jpg

Edited by bbowl
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Check to see if the shell in the magazine directly underneath the bolt has a cut in the hull. The foot that pushes the shells out of the magazine, may have a sharp edge on it, digging into the shell beneath it. Also check the face of the foot where it slides across the base of the case head. The foot's face needs to be polished smooth and either perfectly flat or angled slightly toward the center of the bolt. If it's rough or angled outward, you will get the same problem.

 

Tony

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Check to see if the shell in the magazine directly underneath the bolt has a cut in the hull. The foot that pushes the shells out of the magazine, may have a sharp edge on it, digging into the shell beneath it. Also check the face of the foot where it slides across the base of the case head. The foot's face needs to be polished smooth and either perfectly flat or angled slightly toward the center of the bolt. If it's rough or angled outward, you will get the same problem.

 

Tony

Maybe I need to add to a statement that I often make....

 

"There is no substitute for metalworking and , gunsmithing .... and experience.

 

Tony,

You don't chime in much, but when you do, it is usually enlightening, efficient, and a look into the more intricate side of these weapons.

 

evl....

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Check to see if the shell in the magazine directly underneath the bolt has a cut in the hull. The foot that pushes the shells out of the magazine, may have a sharp edge on it, digging into the shell beneath it. Also check the face of the foot where it slides across the base of the case head. The foot's face needs to be polished smooth and either perfectly flat or angled slightly toward the center of the bolt. If it's rough or angled outward, you will get the same problem.

 

Tony

Maybe I need to add to a statement that I often make....

 

"There is no substitute for metalworking and , gunsmithing .... and experience.

 

Tony,

You don't chime in much, but when you do, it is usually enlightening, efficient, and a look into the more intricate side of these weapons.

 

evl....

 

ETA: if a mod sees this, is there any way to change the -1 that I just accidentally gave Tony's post? I hate this damn iPhone! I know Tony probably doesn't give 2 shits about it, but I do. Any help appreciated.

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Check to see if the shell in the magazine directly underneath the bolt has a cut in the hull. The foot that pushes the shells out of the magazine, may have a sharp edge on it, digging into the shell beneath it. Also check the face of the foot where it slides across the base of the case head. The foot's face needs to be polished smooth and either perfectly flat or angled slightly toward the center of the bolt. If it's rough or angled outward, you will get the same problem.

 

Tony

Maybe I need to add to a statement that I often make....

 

"There is no substitute for metalworking and , gunsmithing .... and experience.

 

Tony,

You don't chime in much, but when you do, it is usually enlightening, efficient, and a look into the more intricate side of these weapons.

 

evl....

 

ETA: if a mod sees this, is there any way to change the -1 that I just accidentally gave Tony's post? I hate this damn iPhone! I know Tony probably doesn't give 2 shits about it, but I do. Any help appreciated.

 

I +ed him for you. I was thinking the same thing even before I read your post. If Tony says something, you probably need to pay attention.

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Check to see if the shell in the magazine directly underneath the bolt has a cut in the hull. The foot that pushes the shells out of the magazine, may have a sharp edge on it, digging into the shell beneath it. Also check the face of the foot where it slides across the base of the case head. The foot's face needs to be polished smooth and either perfectly flat or angled slightly toward the center of the bolt. If it's rough or angled outward, you will get the same problem.

 

Tony

 

It does not appear that this is the case and even when the magazine is removed it is still stuck. The bolt is not getting stuck on the next shell in the mag the shell is being pushed into the chamber at a wrong angle. This is due to the lower "foot" not having the shell inside its grasp as you can see in picture 2. To properly chamber the shell needs to be inside of that foot.

 

You can see in pic #1 that the extractor has the shell in the proper position its just that lower foot that it isn't in causing the shell to enter at a slight upward angle and it gets wedged.

Edited by bbowl
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Check to see if the shell in the magazine directly underneath the bolt has a cut in the hull. The foot that pushes the shells out of the magazine, may have a sharp edge on it, digging into the shell beneath it. Also check the face of the foot where it slides across the base of the case head. The foot's face needs to be polished smooth and either perfectly flat or angled slightly toward the center of the bolt. If it's rough or angled outward, you will get the same problem.

 

Tony

 

would you mind attaching a pic of the foot you are talking about that is properly angled and polished? much appreciated

Edited by bbowl
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Check to see if the shell in the magazine directly underneath the bolt has a cut in the hull. The foot that pushes the shells out of the magazine, may have a sharp edge on it, digging into the shell beneath it. Also check the face of the foot where it slides across the base of the case head. The foot's face needs to be polished smooth and either perfectly flat or angled slightly toward the center of the bolt. If it's rough or angled outward, you will get the same problem.

 

Tony

 

would you mind attaching a pic of the foot you are talking about that is properly angled and polished? much appreciated

He is talking about the one that touches the shell on the way into the chamber. It is opposite of the extractor on the bolt face.

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Check to see if the shell in the magazine directly underneath the bolt has a cut in the hull. The foot that pushes the shells out of the magazine, may have a sharp edge on it, digging into the shell beneath it. Also check the face of the foot where it slides across the base of the case head. The foot's face needs to be polished smooth and either perfectly flat or angled slightly toward the center of the bolt. If it's rough or angled outward, you will get the same problem.

 

Tony

 

would you mind attaching a pic of the foot you are talking about that is properly angled and polished? much appreciated

He is talking about the one that touches the shell on the way into the chamber. It is opposite of the extractor on the bolt face.

 

I understand that, it is the protruding piece in my second picture on the bottom of the bolt, correct?

 

I was asking if someone can show a picture of one that has been properly angled and polished so i know what to do with mine. I have a good idea of what he means but not quite ready to remove metal based on that.

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I think my problem was centered around some of my mags not having a decent feed angle. I doesn't happen with my AGP or down loading my promags

 

sorry, what do you mean by "down loading"? Loading less than capacity?

 

And, by feed angle you mean the angle the shells sit in the mag, or? I don't see anything of a feed ramp or anything like that in my factory 5s or my surefire 10

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I never really bothered with that area as I knew it was bad juju. I'll be back....

 

post-22401-0-98589400-1312086285_thumb.jpg

 

The top is a bolt with only a few rounds on it, 5 I think. The bottom bolt is out of the "Flawless" S12. I has quite a few rounds on it.

Edited by evlblkwpnz
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I think my problem was centered around some of my mags not having a decent feed angle. I doesn't happen with my AGP or down loading my promags

 

sorry, what do you mean by "down loading"? Loading less than capacity?

 

And, by feed angle you mean the angle the shells sit in the mag, or? I don't see anything of a feed ramp or anything like that in my factory 5s or my surefire 10

 

Down is loading less than the max. It would hang up with 10 in the mag but If I started with 8 or 9 it wouldn't.

The feed angle is determined by the magazine follower. I'll e looking at it later today.

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can't really see bottom bolt. plus could you also do a side view? the more comparison pic angles the better. thanks for you time it will really help

The "foot" that Tony was talking about is on top. I cropped part of the bolt because I have something going on there that I haven't seen anyone doing before. It is one of the reasons that I always use this weapon for my dump videos. I am trying to make sure it isn't a bad idea before I share it with anyone. I would hate to have someone see it, copy it, and have their bolt fail later. So far, I have around 2k rounds on the mod and it runs better than any other S12 that I have owned or seen in person. When I get to 5k, I may start a thread explaining the mod and exactly what to do. Until then it is "Top Secret" :ph34r:

 

I will get another pic of the factory bolt....

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Try taking the follower out of the factory 5 rd mag and put it in the surefire. IF it doesn't fail to chamber its an issue with either the follower or the gun, but since you said the agp and the promags don't do this as well as the factory mags it may be the follower. I had the same issue with my gun when i got it and it didn't like the surefire at all. I bought a few of the repro factory 5 rd mags from keep shooting and too the followers out of those.

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Try taking the follower out of the factory 5 rd mag and put it in the surefire. IF it doesn't fail to chamber its an issue with either the follower or the gun, but since you said the agp and the promags don't do this as well as the factory mags it may be the follower. I had the same issue with my gun when i got it and it didn't like the surefire at all. I bought a few of the repro factory 5 rd mags from keep shooting and too the followers out of those.

 

I never said anything about agp and promags, i own neither. I did say that the problem happens with both my factory 5s and my surefire 10.

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Well that will teach me to post before the coffee has kicked in. Though try changing the follower out from the factory mag to the surefire and see if it still does that.

 

Since i have the same problem with all 3 of my mags (2 factory 5 1 surefire 10) i dont see how swapping parts between them would help anything. I dont believe the magazines are the problem here since they all have the same problem.

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  • 1 year later...

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