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Aero M5 build. Buffer spring options


ShadowAviator

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1 minute ago, 98Z5V said:

This is the only thing standing on your way of "what we've figured out as a Standard" to making these things run.  The only thing.

If your gun doesn't run - replace the spring with one of the known good springs we'e mentioned, and try again. 

 

Yeah, I will give the Tubbs a try.  I wanted to get the gun up and running reliably, however I love to tinker.  Thats why I like ARs.  

Once this rifle is done, the next project is to rebarrel my Tikka T3x to 375 Raptor.  After that, who knows.  

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I appear to be getting some failures to extract. Seemed to happen with various ammo, from whitebox M80 to different boxes of hunting ammo I had.  I can't remember if the FGMM had issues or not.

Barrel and bolt headspaced okay.

Bolt is the double ejector type. (Toolcraft from Arm or Ally)

I had disassembled the bolt for cleaning before ever shooting it.  Everything seemed to function fine.  Ejector went in smoothly, no burrs on extractor.  Extractor springs were the "spring in a spring" type with an o-ring.

I did notice some marks from the extractor on a case rim, so I thought maybe overgassed (shouldn't be, but worth checking).  Gas block was wide open, so I starting closing it down.  Gas was low enough to not lock back on empty, and I was still getting some failures to extract.

My next thoughts are either the extractor in some way, or a tight or rough chamber that didn't want to let go.

For now I plan to get another extractor (even if I don't need it).  Any suggestions on a good brand to get an extractor from?

Also plan to check the chamber as best I can and make sure its clean.

Any other thoughts or suggestions?  I will be pulling the bolt apart again to look closer at everything.

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14 minutes ago, ShadowAviator said:

50ish rounds through it so far.  I don't think it is a "breaking in" issue though, at least I don't think so.

Gas block needs to seal to the barrel.  Gas tube needs to seal inside the gas block.  Carbon fouling is what does that, and creates the carbon seal on those parts, in those locations. 

50 rounds is barely scratching the surface to get that done - not enough rounds.  Sometimes, it might take 200 rounds.  Depends on who made all the parts, how easy (or hard) they went together (indicating tighter tolerances)...  

Shoot the gun more.  :thumbup:

Edited by 98Z5V
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4 minutes ago, 98Z5V said:

Gas block needs to seal to the barrel.  Gas tube needs to seal inside the gas block.  Carbon fouling is what does that, and creates the carbon seal on those parts, in those locations. 

50 rounds is barely scratching the surface to get that done - not enough rounds.  Sometimes, it might take 200 rounds.  Depends on who made all the parts, how easy (or hard) they went together (indicating tighter tolerances)...  

Shoot the gun more.  :thumbup:

Could the extraction issue just be that it needs a little breaking in?

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16 minutes ago, ShadowAviator said:

Could the extraction issue just be that it needs a little breaking in?

The extraction issue could be that - you don't have a good gas seal yet, and have gas escaping, and don't even have the full gas power available until those specific parts are all sealed up. Definitely, could be.

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25 minutes ago, 98Z5V said:

The extraction issue could be that - you don't have a good gas seal yet, and have gas escaping, and don't even have the full gas power available until those specific parts are all sealed up. Definitely, could be.

Sorry, I just noticed I didn't describe the issue.  The cases are being left in the chamber.  There is plenty of gas to cycle the action and lock the bolt back.

It would try to feed the next round, but would jam since the spent casing is still in the chamber. I would clear the mag out, and slam the bolt home on the spent casing and then it would extract. Usually took a little more force than normal on the charging handle to extract at that point.

 

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Pics of specific parts will help here.  Post a pic of the extractor claw.

What recoil spring are you using now?  I didn't see a mention on what's in there right now.

You still need more rounds through the gun, regardless of those answers, and it needs to be lubed well whilst shooting more.

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They're square. Square ejectors cause problems.  Been documented gun-board wide.  Not saying this is your problem, but it could be feeding into some of the problems you'll see. 

Bottom line - you need to shoot the gun more.  Secondary line - ejectors should have round faces, not square faces.  Maybe something to look at.  Maybe something to address - after you get more rounds through the gun. 

Ejector faces should look like this:

1042333125_squareejectors.thumb.png.a8603e53e742713c09271ca42e042a30.png

Just something to think about.  Might not be the issue, but square ejector faces ARE an issue.

Edited by 98Z5V
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The lug "wear" might be normal.  Looking closer, I can see some coating on the angled part.  Do they normally come with a beveled corner like that?

 

This may seem unrelated, but would anyone know the cam pin diameter?  In thousandths?

I had put a Lantac domed cam pin in to help with wear on the upper reciever.  It was something I have done on my AR-15s, though looking at it now probably not needed.

Anyway, the Lantac pin measures 0.366, but the original toolcraft measures 0.371.  

Edited by ShadowAviator
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1 minute ago, shooterrex said:

I have the problem of leaving the case in the chamber with my 5.56 pistol. Only when I use steel case ammo. The bolt is moving too fast before the case shrinks enough to be extracted.

Your BCG might be running a little fast. A heavier buffer or less gas may solve this issue.

I dialed the gas back until it would not lock the bolt back and was still having cases stay in the chamber sometimes. 

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If your gas block and tube are not sealed up with carbon yet that could happen and still be a bit over gassed. Not saying that's it, just a possibility.

A bit of flitz on a bore mop in the drill on low speed to polish the chamber a little might not hurt.

You don't want to polish the chamber so smooth it can't hold on to the case when it fires.

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36 minutes ago, ShadowAviator said:

The lug "wear" might be normal.  Looking closer, I can see some coating on the angled part.  Do they normally come with a beveled corner like that?

Ask the manufacturer that question.  Not us.  We don't know how they manufactured it.

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