Help me love my m305.

Tires

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I bought a 'used' 2013 m305 a couple months ago.

It apparently had no rounds through it, but came with USGI op-rod/spring, USGI fibreglass stock, aftermarket flash suppressor and a scope mount, perhaps more but I can't recall (As you can tell, I am a m305 noob).

Well, after about 60 rounds, I have yet to put a magazine through it and have all 5 rounds fire properly.

First, the scope mount causes ejection issues. You can bet about 3-4 times out of 5, a casing will get caught in the bolt. I noticed m14.ca specifically states their scope mount addresses this issue so it seems to be common.

But also early on I noticed that whether or not it caught the casing, even though it loaded the next round, the trigger wouldn't #### and the rifle wouldn't fire.

I searched the #### out of this (hopefully this trigger problem hasn't been addressed and is sitting right under my nose). I've broken the rifle down, cleaned it numerous times, greased it, cleaned the gas system at least 3 times now.

Well, yesterday I finally took the scope rail off, thinking that was causing the problem - Nope. Although casings no longer can be caught up in the bolt, it still often fails to #### the trigger after the shot. Last magazine, out of 5 rounds, it cocked once.

If I rack the bolt manually, the trigger cocks every time.

I'm hoping someone here can lead me to an answer.

In breaking down the rifle I've noticed a few things that concern me:

-The gas piston is 'sticky'. Even after a fresh cleaning, it doesn't move freely. It will move back an forth slowly with the tilt test but it seems to have a vacuum effect. Now I've read about the gas system shims, but I cant conclusively say the rifle needs it. After the last cleaning I did check the alignment of the holes (also checked that they were clean and cleared) and they seem to be fine, perhaps the slow movement of the piston says otherwise?

-The gas piston often seems to jam up a little. Sometimes after loading a round (manually or semi-auto fire) the bolt stops short about an inch from completely closing. I believe this is the piston jamming up. The part of the piston with the notch doesn't seem to fit quite flush in it's housing (?), or has to much room to play, leading to binding.

-The bolt 'arm' (underneath the barrel, the part that meets the gas piston) sits a little off, I don't know if this is a cause for concern, just doesn't look right.

That's about all I can think of at the moment. I've been googling and searching here but have found nothing about anyone else having this trigger issue. The honeymoon stage is worn off and I'm really starting to get bummed I have this supposedly brand new rifle that doesn't shoot worth a crap.

So, Anyone have an idea's??
 
First of all, welcome to the forums and the M305 addiction. Check the stickies in the Battle Rifles section, there is an incredible wealth of into on these rifles, including many initial function tests. Sometimes an incorrectly fitted stock can cause issues with the trigger group, potentially dangerous issues. The scope mount problem is common, and can be fixed through another type of mount, or by trimming the extractor springs.

As for the op-rod alignment with the piston (I think this is what you are talking about), mine is slightly off centre as well, and it doesn't seem to affect function, but could be an indicator of an incorrectly indexed barrel.

As far as I know, the gas piston shouldn't just drop and float around too freely, at least mine doesn't. Regardless, I don't THINK this would cause the other issues you speak of (unless it is in fact jamming completely somehow). Someone more knowledgeable than me will chime in here any time now.
 
You're rifle sounds like it doesn't pass the function test, which would be the most significant problem, safety wise.

Read the stickies at the top of this forum thoroughly.


The slow moving piston is good. You want to seen the vacuum effect, provided the vent holes line up.
I'm curious to know if your barrel index and op rod guide (the "bolt arm") is off. That may explain the binding. The op rod guide may also be binding up on the stock as well.
The ejector spring on the norc M305 is too strong for most scope mounts. The casing flicks out with too much force and bounces off the underside of the scope mount, getting knocked back down in front of the closing bolt and causing jams.
Cutting a few coils off the ejector spring helps.


Where are you located? Can you post pictures?
 
By the way, I initially hated the M305 and regretted buying it, because of all the tinkering mine required. Now I love it and bought two more, just to keep tinkering.
 
Tires, what is your location?

The gas piston is 'sticky'. Even after a fresh cleaning, it doesn't move freely. It will move back an forth slowly with the tilt test but it seems to have a vacuum effect. ... After the last cleaning I did check the alignment of the holes (also checked that they were clean and cleared) and they seem to be fine, perhaps the slow movement of the piston says otherwise?

This sounds OK; you want the piston to slide slowly due to minimal airflow around the piston. The piston will fall slowly as air enters the chamber in front of the piston through the gas port in the barrel.

-The gas piston often seems to jam up a little. Sometimes after loading a round (manually or semi-auto fire) the bolt stops short about an inch from completely closing. I believe this is the piston jamming up. The part of the piston with the notch doesn't seem to fit quite flush in it's housing (?), or has to much room to play, leading to binding.

Remove the piston and see if the breech block/bolt closes reliably. Do NOT do this at home with a live round. Use an empty case or make a drill round (case and bullet only)

-The bolt 'arm' (underneath the barrel, the part that meets the gas piston) sits a little off, I don't know if this is a cause for concern, just doesn't look right.

The barrel has a guide for the op rod. Is that holding the operating rod offset a bit? Th is might be the biggest part of it.
 
By the way, I initially hated the M305 and regretted buying it, because of all the tinkering mine required. Now I love it and bought two more, just to keep tinkering.

When I first got my M305 it went from the box to the safe and sat for about three months... I grabbed it and did an inspection and noticed the rear sight was so bad the leaf spring cover would not even seat... some hammering and heat I got it to shape close to what is should have been and so I could use it if needed... then it went back till my new parts came in...
 
Thanks for the quick replies guys, hopefully this is what you wanted to see:




Looks like there is a bit of rubbing going on there, too. Normal?

Located in Sask.
 
That is about how mine looks, and mine functions just fine. Not perfect, but I have seen much worse. Check the little hoop that is attached to the barrel that the op rod goes through (known as the op rod guide), and see if it is loose of seems firmly in place. If it is loose, you may want to use some Lock Tite on it to make sure it doesn't move around, and keeps the alignment proper.

When I switched my guns's stock, the screws that held the front sling plate on were actually protruding too far in due to the difference in thickness in that area, and were scraping the bottom of the op rod. Hard to tell from the pictures if that is what is going on, but it is certainly a possibility. I should also add that this won't cause any functional problems other than a bit of binding and grinding when the op rod moves, and obviously cosmetic damage.
 
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I don't see anything terribly wrong in either of those two pictures.

Too back your in Sask. Barney (TacticalTeacher) is an excellent resource on ironing out all the kinks in these M305s (they're essentially do-it-yourself "kit" M14 rifles)

can you post some pictures of the op rod guide (the figure 8 shaped thing that goes around the middle of the barrel and holds the op rod pictured in those two pics)
 
Just did the safety test, and the rifle failed the first step. (Put on safe, molested the trigger and caused it to 'fire').

Yep, Tarantula, I had the same issue with the screw rubbing, forgot about that. I've since switched it back into a stock norinco stock, originally I thought maybe something was up with the stock or how it was sitting in it, obviously not the case.
 
Yeah, I ended up having to find some shorter screws that would work. I'm sure there is info in the stickies on the what to do if your rifle doesn't pass the safety test, or you could try sending TacticalTeacher a PM, he is a really great guy, although I am sure he will turn up on here sooner or later.
 
hard to tell from the first pic, but the op rod guide appears to be a little off. Might be enough to cause some binding
003.jpg
 
I never tried the safety test in the USGI stock, other than that the problems in the original post were occurring in the USGI stock and present in the norinco stock.

The guide appears to be a little off to the side, yes, same as the rod.
 
Just did the safety test, and the rifle failed the first step. (Put on safe, molested the trigger and caused it to 'fire').

does it fail the second part (hammer stays back after action racked while trigger is held back in firing position)?
 
Just sitting here playing with the trigger, the safety function works fine out of the stock, what could be going wrong from my hands into the stock?
 
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