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

DarceMegarce

DarceMegarce

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Purchased a new 2013 M305 full length because it looked to good to pass up on and I heard they may be getting pricey soon but now I've got myself into a bit of a project getting it to run smoothly. Not that I mind of course that's what I wanted but I've run into an issue that I haven't read about before so I'm not sure how to fix it, maybe some experts can help?

So my situation; Indexed fine, the iron sights are aligned and on target with both the front post and rear aperture centred. Very impressed with that! Trigger assembly fits into the stock snugly but not overly tight and it always passes the trigger test after assembly so no issues there. My gas system needs to be shimmed as the lock gets hand tight about 30 degrees past alignment with the cylinder. Now the rifle came with a single 5 round magazine and I'm sure there is some issue with it's feel lips because it's very difficult to load and does not strip very well at all but I'm having a failure to feed issue that is actually pretty terrible and it's not just the mag.

My operating rod is binding terribly in the oprod guide at about half way through the travel to the rear and all the way until the last cm of travel. I mean really terribly binding so that I can barely get it to unjam by hand. This happens every time I try and cycle by hand or while firing a live round, with the bolt removed, with the stock removed and with the trigger assembly removed, and also when the operating spring is removed. Strangely the oprod guide does not look out of alignment but when I gave it about 25 hits to cant it to the side of the receiver with the oprod tracks some more it actually passed the "tilt test" so at that point I thought it was fixed...

Well today after the first round fired the binding returned because my oprod guide was pushed back out of alignment when I fired. So clearly the piston is also out of alignment and pushing on the oprod unevenly and canting my oprod guide out of alignment so that my oprod starts to bind. Also I don't remember the oprod binding when I first bought the rifle so it's like the oprod guide is being pushed out of alignment by cycling the action or perhaps when I remove the oprod for stripping? or just firing? I'm not sure.

So, how do I get my gas cylinder to align properly? I can fit a small allen wrench through the gas port holes into the barrel just fine and it ejects fine so it seems like the gas cylinder is aligned well with the barrel but my oprod guide is getting pushed out of alignment by the gas piston not striking directly on the centre of the oprod face. I can see that they are not aligned when assembled. The gas piston is striking low and to the left on the face of the oprod when looking at it from the muzzle end. So I guess that's why I can make it pass the tilt test (both the piston and oprod with bolt installed) and then fire it once and it's binding so badly again that I have to use a lot of force by hand on the oprod just to get a fresh round to strip and chamber.

Of course the binding is far worse when loading rounds from the magazine, it's so bad I would say it's barely functional and dangerous because getting the bolt into full battery is difficult the way it's feeding now and I don't want to blow up my rifle (and my face)! At the same time don't bother suggesting that I return it I'm determined to get this one to run I've never seen one indexed this well before and I know she'll run and be a shooter too I just have to get my sh*t straight!

Let me know if I need to take pictures of anything to help you guys get what I'm saying!
 
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One.

Oprod guide should not be loose, period.

Remove guide, dimple and reassemble using proper lock tight. Replace spring pin.

Once you have done this get back to us.

Could be a bent oprod but we won't know anything until the guide gets fixed.

More info like what ammo you were using and lots and lots of pictures.
 
pictures please.

did you remove the retaining pin on the op rod guide before you tried to realign it by hitting it 25 times?
 
I can't seem to get that little pin to budge but the oprod guide does have a good amount of play. I should rephrase: I tapped the oprod guide about 25 times with a mallet to get it into proper alignment to pass the tilt test the first time. Then I shot the rifle and the oprod guide was pushed out of alignment again and the binding came back.

So after that I have the oprod quide one good whack with the mallet and that pushed it back into proper position. Again though, fired one round and it got pushed back out of place.

It looks like I will have to affix the oprod guide into it's position more permanently. I don't want to remove the retaining pin if it isn't an absolute must. What I would like to do is tap on the oprod guide with my mallet until it seems like the oprod is passing the tilt test and still as aligned with the gas piston as possible and then I will apply JB weld on the outside of the guide where it meets the barrel rather than trying to get the oprod guide properly aligned after it's been re-pinned back on.

I also plan to unitize my gas cylinder and front barrel band with JB weld and not use shims because the epoxy will be a spacer! Thoughts?

I'm working on some pics my camera seems to be too low definition to get much to show up though.

And I have been using the cheap Norinco steel cased 7.62X51 but I have just purchased some S&B brass cased 147gr .308 FMJ to continue testing with instead of the steel cased stuff which does seem to complicate my feeding issues.
 
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Do it right. Pull the pin. Remove the guide. Dimple the barrel. Reinstal guide. Put in a new pin.



Do it right or don't do it at all. You'll find people will be more helpful if you dont jerry rig your gun.
 
I wonder if the Op Rod is hitting on the stock somewhere? Doesn't seem right that it should bind up that bad on its own.My op rod guide is quite loose but have not had any binding issues, I am replacing my stock and will fix my loose Op Rod then, but for now it seems to not cause any binding.
I would take the stock off and cycle the bolt quite a few times to see if it happens when out of the stock?
Rodney
 
My guess is that the op rod guide is out of alignment then.

As Yomomma wrote, take out the pin and then properly align the op rod guide. then see if the hole for the pin in the guide lines up with the groove for it on the barrel.

you've read the sticky about dimpling the barrel boss for the op rod guide to make it fit tight?

Also, are you absolutely sure the op rod itself is completely straight?
 
Yes the binding still happens when the barreled action is removed from the stock so it can't just be rubbing on the stock. I'm thinking maybe the gas cylinder is canted to a position between 6 and 7 o'clock when looking from the butt. It's just enough to knock my loose oprod guide out of position to a 6-7 o'clock position as well when cycling during firing. That's what causes the binding so likely I just need to get the oprod guide fixed to the correct position well enough that the misaligned gas cylinder and piston can't push it over so it binds. I'm still deciding how I want to go about doing that though...
 
I agree Yomomma and I want to get that darn pin out so that I can position the oprod guide a bit better but I think the reason I'm having so much trouble is they broke it during the stippling process. It's really been rammed in there like a bugger and maybe they broke it so that's why my oprod guide is loose and getting kicked out of alignment?

I got the idea to use an epoxy to hold the oprod guide in place from this thread from another forum here: http://m14forum.com/gus-fisher/119852-m14-op-rod-binding-does-not-pass-tilt-test.html

A. Reach up and grab the ORG and see if you can move it to the right or left. If you can move it by hand, the ORG is really too loose. The Technical Manual (TM) calls for replacement with a new ORG that fits the barrel tighter. However, you can stipple the barrel under where the ORG sits, or you can knurl the barrel or even stipple and epoxy glue the ORG in the correct position.
Click to expand...

I have come to the conclusion that EVERY ORG should be stippled and epoxied to the barrel AFTER you ensure the OR slides freely AND the ORG centers the OR on the Gas Piston
Click to expand...
 
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Odd Shot said:
My guess is that the op rod guide is out of alignment then.

As Yomomma wrote, take out the pin and then properly align the op rod guide. then see if the hole for the pin in the guide lines up with the groove for it on the barrel.

you've read the sticky about dimpling the barrel boss for the op rod guide to make it fit tight?

Also, are you absolutely sure the op rod itself is completely straight?
Click to expand...

I need to find that sticky and I'm pretty sure the oprod is straight but I don't have anything to compare it to. The only thing that doesn't look straight is the gas cylinder and it's somewhere between the 6 and 7 o'clock position (when looking from the butt of the rifle).
 
I'm thinking I will have to grind the pin out of there in order to get it out. Haven't been out to Niagara in forever! I'm thinking a replacement won't be necessary it seems to me like the pin and the guide will never hold true on their own. I'm going to look over what info I can find about mounting the oprod guide in a manned which allows me to align it properly before fixing it in place.
 
Okay well the actual binding seems to be occurring where the oprod glides against the bottom of the barrel near the chamber, on the ridge on the side that the oprod handle is on. It's completely rubbed the finish to a high sheen on the beginning of the ridge. Does this mean my oprod is likely bent as well or is that simply caused by the oprod guide being canted to the 6-7 o'clock position when looking from the butt of the rifle?
 
DarceMegarce said:
Yes the binding still happens when the barreled action is removed from the stock so it can't just be rubbing on the stock. I'm thinking maybe the gas cylinder is canted to a position between 6 and 7 o'clock when looking from the butt. It's just enough to knock my loose oprod guide out of position to a 6-7 o'clock position as well when cycling during firing. That's what causes the binding so likely I just need to get the oprod guide fixed to the correct position well enough that the misaligned gas cylinder and piston can't push it over so it binds. I'm still deciding how I want to go about doing that though...
Click to expand...

I think you've revealed the problem.

If the gas cylinder is rotated such that it is in a position between 6:00 and 7:00 when viewed from the butt of the rifle, and then that the op rod guide is also similarly canted, then I would surmise that the barrel is in fact slightly under indexed (regardless of what your sight picture is).

Tightening the barrel on the receiver to proper index it (so that the gas cylinder is exactly at the 6:00 position) should similarly position the op rod guide to the 6:00 position and prevent it binding on the op rod itself.

I had a similar problem with my over-indexed barrel. Properly indexed, it would pass the tilt test and the op rod no longer got bound on the op rod guide (and the barrel flange)

Try posting some pics along the axis of the barrel from the muzzle end, pls.
 
Thank you I think you might be correct! I may just take a step in that direction instead towards getting this thing straitened out! I'm going to do my best on an alignment pic from the muzzle end to show you what I see!
 
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