Expert advice needed for new M305 owner

thatmikeguy

thatmikeguy

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I am brand new to the M14 platform so this is a learning curve for me. I've done a bunch of reading online but i'm not quite sure what to do with it all. This same post is in the gunsmithing section. Some one said I should come here.
I'll begin with my problem.
The gun has a lot of trouble feeding a fresh round into the chamber though it ejects every time. By trouble i mean the bolt completely misses the next round and "click".
I pulled it apart and studied it hard and found that the op rod rubs and binds on the barrel. The chamber portion of the barrel to be exact. I could slowly allow the bolt to travel forward and it would actually stop mid travel.
So, i fitted the op rod with my trusty file and a dry erase marker in order to file just enough and not too much. It worked. The op rod no longer binds and the action feels smooth. (relatively) Much better than before.
I only had 7 rounds loaded at the time so i went out for a test run. It failed to feed a fresh round only once and had i miss fire which had not happened yet.
Much better but still less than desirable.
I also noticed that my cases have exceptional growth. I understand this to be somewhat normal in the M14 rifle.
I've spoke with a buddy who has many more rounds experience than i and he tells me i have a head space problem. way TOO much head space.
I've been pondering this and reading online and studying my rifle and this seems to make sense.
My barrel appears to be under indexed. (not screwed in far enough) My gas cylinder is not directly south of the bore. It's a little to the left. My navy gas lock is canted to the right which brings me to mention the op rod band which is pinned to the barrel. It is a little to the left which brings the op rod left and causes the rubbing and binding on the barrel which i remedied but it seems it's merely a symptom of something grander. And, as if that's not enough, i noticed today that the bolt lock up is quite loose.
My biggest surprise in all of this is that the gun is accurate. I'm getting good groups at 100 yards with iron sights despite that the front post appears to be 8" wide at that distance. My first 5 round group was 4". My second was 3" and 3 of those round were hugging like sisters.
I've been using military load data which is 42 grains of varget with a 168 grain hpbt. My brass dribbles out reliably. Right beside me.
I've fired 45 rounds so far. 25 of which were 150 grain campro fmj loaded with 43.5 grains of varget. Those are now gone.
Out of all these rounds, 8 of them had primers creeping out. Not much, but a little, which shouldn't happen.
How many problems am i dealing with here? What's the simplest most cost effective way to deal with this?
I'm on a very limited budget. I want to enjoy my rifle without it becoming a money pit. Thanks for any help.
 
For the failure to feed issues like you describe pull your trigger group and check the roll pin that retains the magazine release.
if the pin is collapsed, the mag will not seat high enough to let the bolt grab a round. Seen this many times with chinese trigger groups.

the other culprit could be stock fit.
to check stock fit to rule out an effect on the magazine to bolt spacing follow this procedure.
#### the rifle by pulling oprod fully to rear and let it slam home
then squeeze the trigger . The hammer should fall. Don not let go of the trigger, keep it held back, fully squeezed. Now rack the oprod again the same way, then release the trigger.... you should here an audible click as the trigger resets and when the trigger is squeezed again the hammer should fall.
If it fails that test exactly as I described, your problem could be the stock fit "and" the rifle is completely unsafe for live ammunition until that fitment is remedied.

assuming the magazine is not faulty ie: spring catching on internal protrusion of limitting rivet..... the above 2 conditions will be the answer.

if this is a 7.62x39 rifle..... it could be something else , the above applies to 7.62x51/308 rifles

have your barrel correctly indexed, check your oprod guide on the barrel for proper alignment

not sure about your reloads but i would be getting the headspace checked and sizing to your chamber dimensions before going there again

contact M14medic
 
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What stock are you using?

Some things to consider for this (or your next) M14:

1) When fitting an op rod, it's not uncommon for the rod to rub on the underside of the barrel. Government arsenals would address this by mounting the barelled receiver in a milling machine and milling a small flat on the underside of the barrel itself to provide clearance. This also aids in dismounting the operating rod. You see this mod on a LOT of Israeli M14's - it's almost as though the IDF made this change whether the rifle needed it or not. I sometimes also have to do it using a NOS op rod on a NOS match barrel, as the journals are often slightly over-diameter.

2) When a bolt in an M14 fails to pick up a round, and assuming your mag catch is correctly made and the roll pin is OK, then I suspect the stock. Remove the barelled action from the stock, install the trigger group (without stock) and measure from the top of the mag catch to the top of the receiver safety bridge with callipers. Re-install the stock and make the same measurement. I suspect you will see that your trigger group is not seating deep enough into your stock. If this is the case, the remedy is to inlet the trigger group incrementally into the stock until the magazine presents the round high enough for the bolt to pick it up reliably. Chinese trigger groups are not exactly the gold standard in consistency, so swapping in a GI or BULA trigger housing might also fix your issue. Wolverine may have some still for sale.

3) Long headspace is not unusual in an M14. If it passes a NATO field gauge, you would be safe, but I would not try to reload your fired brass unless the headspace is within SAAMI specification. This could be corrected either with a new barrel chambered to your bolt, or a new bolt with longer locking lugs (i.e. USGI, LRB, BULA, FA, etc.). If you are on a budget and don't reload, just get it checked with a field gauge and if it passes, stop worrying. If it fails, you need to pursue a fix.

4) You can improve your barrel indexing, no problem. The repair is to remove (and throw away) the useless set screw in the receiver ring and to use a barrel vise and action wrench to index your barrel. To do this properly, you need a good quality flash hider (i.e. NOT a chinese one) that will engage your barrel splines and provide a properly square flat (i.e. the dovetail where a front sight would be installed). Place a parallel bar on the top of the flash hider and one across the rear sight shelf flat (on the receiver heel). Tighten the barrel until both parallel bars are parallel to one another. This will also often improve your op rod fit, making it less likely to bind. It will also slightly shorten your headspace (a good thing in your case).
 
Thank you for the info.
The rifle has the factory stock. I do not have any others stocks. The original glad hider/front sight assembly was previously removed to install a brake and the rifle now wears a navy gas lock sight. I will have to check the stock and trigger group as suggested. I have been tempted to attempt indexing the barrel except I have no tools specifically for this. I have tried both of my 2 mags and the performance between the 2 are equal. Sometimes it will fire 5 rounds perfectly and in the very next 5 rounds it fails to feed some and I have not discovered any rhyme or reason for it. Since fitting the op rod, performance has improved but it's still lacking. I wonder if the op rod binds in the guide or maybe, like you said, the trigger group isn't holding the mag in far enough (paraphrased)
 
thatmikeguy said:
Thank you for the info.
The rifle has the factory stock. I do not have any others stocks. The original glad hider/front sight assembly was previously removed to install a brake and the rifle now wears a navy gas lock sight. I will have to check the stock and trigger group as suggested. I have been tempted to attempt indexing the barrel except I have no tools specifically for this. I have tried both of my 2 mags and the performance between the 2 are equal. Sometimes it will fire 5 rounds perfectly and in the very next 5 rounds it fails to feed some and I have not discovered any rhyme or reason for it. Since fitting the op rod, performance has improved but it's still lacking. I wonder if the op rod binds in the guide or maybe, like you said, the trigger group isn't holding the mag in far enough (paraphrased)
Click to expand...

There are many different "factory stocks" - what exactly do you have? And just because it is "factory" does not mean the stock is fitted properly. Moreso if it's a Chinese stock.

I know your FH is not on the rifle (I gleaned that from your first post). Even if it were, I NEVER index a barrel using chinese FHs - none of them are square. they are almost all cheaply sand cast abominiations. I use USGI or SAI FH's for indexing exclusively. If I don't have one, to use, then Id go by centering the feed ramp cut triangle on the slot for the operating rod guide - that isn't great, but it'd be infinitely better than eyeballing your navy sight or using a chinese flash hider to index a barrel on an M305.

If you don't have to tools to index your barrel, DO NOT try it with jerry-rigged tools. You WILL mess up the receiver, the barrel, or both. This is one area where you will need to find someone with the tools who will work for beer, or take it to a gunsmith.

It's very unlikely that op rod fit is causing your feed issues if it's not obviously binding. I assume you have tried and passed the tilt rest? (google it if not sure).

Honestly, I suspect the mag is not sitting high enough because of your trigger group fit.
 
thatmikeguy said:
I made the measurement as described. At most, there is a .010" difference when the barreled action is in the stock.
Click to expand...

10 thou would not make a big difference.

Do you know anyone else with an M30 or M14? If so, I'd be curious what would happen if you used another trigger group in your rifle. It's possible the geometry is off on yours.

Also, does it feed OK if you cycle dummy rounds by hand? Another possibility is the rifle could be short-stroking, prevending the bolt from travelling rearward enough to pick up the next round.

I also hope/assume you are NOT using a plastic or rubber op rod buffer...?

Is the gas system really dirty?

Have you played withthe gas system at all? Is it shimmed? Have you checked to ensure the gas port is still aligned with your gas cylinder port?
 
The gas system is not shimmed. I did check port alignment. It looks good.
I discovered that I can lift the mag off of the mag catch and thereby raise the mag about .020" in the rear.
I don't think the gas system is dirty. I did have the piston out. I lightly oiled it. That's why I was wondering about the op rod binding. It doesn't feel like it is but I don't know if it is while under stress. There is no rubber buffer. Are my loads to mild? I got the load recipe from a buddy who shorts his M305 a lot and he says it works great. His brass ejects far. Mine does not. My brass dribbles out.
I'm using 42 grains of varget with a 168 grain bullet.
I do know 2 others with M305 rifles and theirs work. One shoots reloads one does not.
 
Don't oil the gas system. The oil will harden when heated and mixed with soot and will reduce the reliability of the gun.

Also, stop using reloads until you know the gun functions OK. Get some factory stuff and see if your problem persists. If the gun works OK with factory ammo, chances are your load isn't right for that gun.

If the mag can sit higher with hand pressure, then it's possible the mag is sitting too low in relation to the bolt. Are you using the original mag release, or an aftermarket one?

I would also suggest trying another trigger assembly if you know someone else with an M305 - it may eliminate another possible issue.
 
I got the gun 2nd hand. The mag release appears to be original. The previous owner claimed there were no issues. I don't know if he lied or if his ammo was better. He didn't mention shooting reloads.
 
ya, never oil or use any cleaners with preservatives or coating in them. Brake cleaner is best and these parts get no oil internally except for storage purposes.

Does the piston drop like it has some vacuum or is it dropping with no vacuum? some vacuum is necessary.
If it passes the trigger/stock fit tests..... and binding of the oprod can be ruled out.... and the gas system appears okay..... I would be closely looking at the bottom of the bolt where is engages the round in the magazine as it pics it up. I'd be inspecting the bolt lugs for excess play in the lug raceways causing the bolt to lift. I'd be inspecting the magazine(s) for quality and tab dimension , are they norinco or usgi mags or some kind of aftermarket mags? And also checking the mag release is not worn. Truly, the only way to know for sure if the mag release pin has failed, it to drive it out and look at it but you will need a new one to drive in to replace it anyways.

I can't believe a seller would sell the rifle saying it worked fine when it obviously had these issues before you got it. A negative trader rating should result for the seller in my opinion. Hopefully you can get her figured out and shooting reliably. I would try federal powershok 150 grain soft points for all your further testing as these have been by far the most reliable ammunition for me and what i used to test customers rifles exclusively.

to me it sounds like a classic short stroke resulting in extracted brass clearing the action but the bolt not travelling back far enough to pick up the next round..... so kinda back to binding or gas system....... puzzling.
 
It does seem to be short stroking.
I just tried manually cycling dummy rounds again and it works every time. I also fiddled with the bolt to see if I could make it pass over the rounds and it does not. I had the recoil spring removed to do this.
The gas piston drops with some vacuum.
So it seems to pass all the tests you guys have suggested.
Thanks for helping. I appreciate it.
I wonder why it short strokes...very odd.
 
I don't actually know what kind of mags they are. They appear to be Norinco mags. They have the same parkerized grey finish. I have one 5/20 round mag and one 5 round mag. Neither one is better than the other which suggests to me that the mags are okay.
 
I very much doubt it's mags. I now suspect it's your reloads not being a good match to your rifle.

As I said, try some factory ammo and go from there.
 
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