New M305s binding operating rod and misaglined rod guide and piston - Help?

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DarceMegarce said:
Not so bad because under-indexing is a simple fix correct?
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looking at the picture, it appears your gas cylinder and op rod guide are out of alignment with the receiver, suggesting that the barrel is out of index.
but it looks like the flash hider (at least the bayonet lug) is aligned vertically with the receiver, which suggests that the barrel out of index but the splines for the flash hider are not aligned properly on the barrel, putting it out of alignment with the gas cylinder.

Is the gas port in the barrel at the 6:00 position or is it also between the 6:00 and 7:00 position?


Indexing the barrel can an easy fix IF you have the right tools (a barrel vice, a sturdy work bench, and a wrench large enough)
 
With the proper tools she should tighten up correctly, if not the barrel will have to come off. Maybe take off .001-.002" from the barrel shoulder on the lathe.
That screw will have to be removed/drilled out at the barrel threads too before correcting the index.

Maybe these guys have a homemade way of doing it.
 
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the gas port looks like it's at the 6:00 on the barrel but is that pic taken with the gas cylinder tightened in its position on the barrel or off? it looks like it's off.

you should still be able to insert an allen key or toothpick into the port on the barrel through the exhaust port on the gas cylinder
 
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mine looks like this (round toothpick through the exhaust port on the gas cylinder, through the gas port in the barrel and visible in the barrel. obviously with the gas piston out of the way)

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Yes that last picture is with the gas cylinder removed. I can still fit an allen key through the gas cylinder's exhaust port all the way into the barrel when the gas cylinder is installed as well. So everything seems fine but the gas cylinder and the oprod guide are not in line with the gas port and flash hider.

Is it possible that the barrel is indexed and it's just the gas cylinder's alignment that's off? I don't want to throw everything else off if it's just the gas cylinder that's not lined up.

Can I just remove material from the barrel flange until the binding stops and securely centre my oprod guide with the barrel gas port and muzzle and leave it at that?

Or will the piston striking the oprod face off-centre damage it over time?
 
pictures of indexing by chalkriver:
http://www.canadiangunnutz.com/foru...Norinco-M305?p=7978776&viewfull=1#post7978776

peened op rod guide boss on the barrel (again by chalkriver)
http://www.canadiangunnutz.com/forum/showthread.php/836327-New-Norinco-M305?p=7968563&viewfull=1#

what my M305 originally looked like: everything was uniformly out of alignment because the barrel was under indexed

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where my op rod was hitting the flange on the barrel (the shiny spot where the parkerization has worn off) because my op rod guide was not aligned properly with the receiver (because the barrel was under indexed)

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DarceMegarce said:
Yes that last picture is with the gas cylinder removed. I can still fit an allen key through the gas cylinder's exhaust port all the way into the barrel when the gas cylinder is installed as well...
Click to expand...

can you post that picture?

it would seem better to have the receiver, gas cylinder and op rod guide properly aligned so that the op rod is not binding on the guide.
 
Here is the allen key with the gas cylinder installed. In this case the key won't fit through to the bore, but a smaller key will. This one is too tight to fit the smaller barrel gas port but it shows just how off my gas cyclinder is from the bore's axis.

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ETA: This is how it looks when it WILL pass the "tilt test". Notice the oprod guide is in the 6 o'clock position and aligned with the barrel axis and but not the gas cylinder.
 
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And here is how the mating between the piston and my oprod look when the rifle WILL pass the "tilt test".

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That misalignment is throwing my oprod guide out of alignment with the bore's axis when the rifle is fired. Right now I feel like if I just securely fix the oprod guide in the 6 o'clock position I should be good to go unless that misalignment between the gas piston and oprod will cause more problems down the road?
 
Any why on earth can I not get my gas cylinder on straight when everything else seems perfectly fine? Did they cut the splines for the gas cylinder off? I can't really tell because there are 3 cuts.

Is it possible that the lands on the inside of the gas cylinder are all wonky?
 
can you post a picture down the muzzle, like the one I did with the toothpick?

The misalignment of the gas cylinder and op rod will not force the op rod guide out of alignment on shooting.

I would guess that the op rod guide is moving back to its original position from your corrected position because that's where it "wants" to be, since that's the way the groove in the barrel boss for the pin and the holes for the pin in the op rod guide line up.
 
Yes I agree that's where it "wants" to be but that's not the 6 o'clock position and I'm still not convinced that the barrel is out of index. Can you tell if it's indexed by the positioning of the ramps in the breech?

I'll work on the down the bore shot!
 
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