So this just happened-- Game over man >.<

grinder08 said:
Hard to be sure from a photo but dark colour on a piece of fractured steel typically means a flaw in the metal. Don't know anything about how the Norinco bolt is manufactured but there are a couple of dark patches on the interior of the fracture and a long dark patch at the top which looks like a crack was there prior to the failure. I would not necessarily say Norinco therefor bad here. All manufacturers have these sorts of problems on occasion. Regardless 150 rounds of 168 should not fail a sound bolt.
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Based on my experience with industrial tooling, it looks to me like the steel was over hardened; possible stress cracks due to the transition between thick and thinner sections; or no tempering or stress relief, but the darker margins do look like stress cracks from shock cooling.
 
Pax+Caritas said:
I could not remember exactly what the manual had to say about ammunition for this rifle, so I went back to re-read it. It indicates that this rifle is designed for standard factory military 7.62 NATO ammunition with harder primers which are less likely to suffer from a slam fire. The manual explains that civilian ammunition with more sensitive primers increase the risk of primer detonation when the bolt slams forward, "slam fire". Could this type of failure be related to a "slam fire"?
.
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No slam fires, was the last shot in a string of 5.

I let the barrel cool somewhat between shots. All the primer strikes up till now (albeit only 148) were uniform and consistent.
I typically check each spent casing before leaving the range to make sure nothing strange is going on with light or heavy primer strikes.
 
Merovingian said:
No slam fires, was the last shot in a string of 5.

I let the barrel cool somewhat between shots. All the primer strikes up till now (albeit only 148) were uniform and consistent.
I typically check each spent casing before leaving the range to make sure nothing strange is going on with light or heavy primer strikes.
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Just glad that you are OK... and hoping that nothing else happens to any of us.

Cheers.
 
Mr Wolverine said:
...

As for your description on operating the action on your rifle, I think what you describe is normal, but difficult for me to be certain without having the rifle in my hands.

With the bolt failure on the gun in question, I will let others speculate as to the cause, faulty ammo, metal failure or a combination, who knows, at least no one was hurt and no major damage was done.
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I could not agree with you more that it is a good thing that the damage was minimal and that no one was injured.

Thanks for your reply and your comment on the movement of the action.
 
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An update if anyone was curious on how my M305 turned out after the bolt failure.

I received the replacement bolt from Wolverine Supplies (Thanks again) and then shipped the works off to the gunsmith to get fitted and checked over.

I just took it out for the first time today. Shot 60 rounds of Federal Power Shok 150gr through it with no issue. The action also feels somewhat smoother now with the forged bolt vs the Chinese one.

A really big thanks to John Hipwell at Wolverine & M14Medic for helping me bring this gun back to life.
Very happy camper !


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Merovingian said:
An update if anyone was curious on how my M305 turned out after the bolt failure.

I received the replacement bolt from Wolverine Supplies (Thanks again) and then shipped the works off to the gunsmith to get fitted and checked over.

I just took it out for the first time today. Shot 60 rounds of Federal Power Shok 150gr through it with no issue. The action also feels somewhat smoother now with the forged bolt vs the Chinese one.

A really big thanks to John Hipwell at Wolverine & M14Medic for helping me bring this gun back to life.
Very happy camper !


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So glad to hear!
 
Weight of a bullet is not a problem for the M1/M14. The powder used to send that bullet downrange is the problem. Heavier bullets require slower burning powder, which means pressure behind the bullet at the gas port is higher than it would be with a faster burning powder. It will eventually bend an op rod. It will NOT snap a bolt lug. Has nothin to do with bolt lug lock up.

Fed GMM uses something like IMR 4064 which is right fine for an M1 or M14 and GMM has long since been popular to shoot in those rifles.

Military loads 168 and even heavier long range ammo, using RL15 etc.
 
Good to know Joel, a good bit of info there. I have a huge stock pile of factory Federal 168 GMM so it nice to hear feeding the rifle them isn't an obvious mistake. I've chatted with alot of folks since the failure I assume to be in the know and 95% of them say the Fed GMM is totally fine, albeit a little pricey for m14 ammo.

I'm in the middle of reno'ing one of the rooms in my home to make a dedicated reloading area. I'll remember you comments when I start start working up loads. :)
 
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I would have the gun checked thoroughly then order a replacement bolt.
Once I was sure the gun was safe, and worked I would sell it giving full disclosure.
Last I would purchase something not made in China.
Just my .02. I am glad you were not hurt.
 
Sakoman .308 said:
I would have the gun checked thoroughly then order a replacement bolt.
Once I was sure the gun was safe, and worked I would sell it giving full disclosure.
Last I would purchase something not made in China.
Just my .02. I am glad you were not hurt.
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Wolverine Supplies mailed me a replacement forged bolt that was was fitted for optimal lug contact by M14 medic.

Sell it ?!? Maybe down the road but not until i've had some fun with it first :)
 
It ain't nothin that 20 minutes and some valve grinding compound from NAPA or UAP wouldn't have fixed, and the M305 gets a lot of new shooters (me included at one point) hooked on the platform. The one I just bought was $599. I'll live with doing some tweaks.

I saw and helped pull a bunch of barrels off of brand new Remington 700 SPS rifles, and checked the lug contact of a few of em. Like 30%-50% each side was common. Yeah, I know, that is enough meat on each side that the lugs won't snap off like that 305 did...but not by much! Also, barrel threads cut so sloppy they use Loctite when they barrel the actions!

I don't feel like I am that short changed or puttin myself under that much risk buyin Chinese guns. But you DO need to be ready or at least know that some tinkering might be in order. At a bit more than $500 for a brand spankin M14, that aint that bad.

The barrels as good as a GI barrel, or at least i should say, shoots as well. And the op rods even better than most! Forged one piece op rod! Only TRW was making one piece op rods. The rest were welding two parts together.

Trigger group is also good to go, etc.

Same on their 1911s and ARs...they rock.

Chit happens, like that bolt but we live and we learn.


Dude, good luck with the renovations and that reloading room! H4895/IMR4895/IMR4064 are gems for M14 accuracy. You can load faster with ball powder and a dispenser if you dont want match loads though.

GMM is 43 grains of what is either 4064 or somethin real close, nothing beyond sane loading there.
 
dimeN said:
yep, it does look like the grain is large on this ... which will reduce the toughness of your bolt ! go and crack a nicholson file in half, a fine grain structure should look like this !! extremely fine !!

when you case harden, its stuck in a high temp with a carburizing medium ... the C migrates into the steel at the outside perimeter ! pending on the steel alloy and the temp they use, it can lead to some grain growth

fulton armory makes a nice bolt.. abit on the over built side !
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I expected to see radial fatigue beach marks when I first saw the broken bolt, but there are none in the closeup pics. It looks to me like a catastrophic fracture due to an overly brittle core. Likely the heat treatment of the part was wrong from the factory. Just my opinion, but under a microscope there could still be fatigue indications. Only so much you can see in a cell phone pic.

I wonder if a specified annealing stage was missed at manufacture?
 
Claven2 said:
I expected to see radial fatigue beach marks when I first saw the broken bolt, but there are none in the closeup pics. It looks to me like a catastrophic fracture due to an overly brittle core. Likely the heat treatment of the part was wrong from the factory. Just my opinion, but under a microscope there could still be fatigue indications. Only so much you can see in a cell phone pic.

I wonder if a specified annealing stage was missed at manufacture?
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I can PM you the higher res versions of the photo if you're curious. Slightly more zoom in detail
 
I don't need a high res photo to see the crystaline structure of that bolt..... We can sit around for a year and talk about how that came to be but bottom line is the bolt was defective and it's very clear in those pics. Damn thing looks cast LOL So I'd say forged with some substandard material and crystalized in the hardening process.
Good thing there were no injuries to you or the rest of the rifle.
Glad to hear you got a new bolt too.
In my experience with the chinese rifles, they have the same design threshold as the usgi rifle they are a copy of. 174gr is the ceiling without gas system mods. Simply shutting off the spindle valve on the side of the gas system enables shooting 180gr if one really feels the need. The damage to the rifle will comes as a bent oprod when bullet grains weights are exceeded, tho I have not managed to bend one or break one yet,
However.... we can throw all that out the window when you get a rifle with a defective bolt. It certainly didn't happen due to the ammo you were using I can confidently say that.
 
45ACPKING said:
I don't need a high res photo to see the crystaline structure of that bolt.....
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I definitely learned a ton from the replies. Solid forum!!

I will likely start using the 168 GMM's again because the rifle really shoots incredible with them.

Only thing left to do is change the muzzle break on it, just got figure out what would be a better choice. I'll start a different thread on that topic or check the stickies so this thread can fizzle out in peace ;)
 
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