Case Head Separation * Updates Post 5 and 12 Big Pic warning*

I really hate to be the bearer of bad news, but from the pics of the receiver right bolt lug recess and pic from behind the safety bridge of the receiver...... she might be toast man. upper left side of the safety bridge , leading off of the firing pin tang recess, looks like something is missing or is really rough.
rear of your bolt looks okay other than the one side of the firing pin tang looks disformed near the end.

I have had cases fail to extract, and the bolt tries to chamber a second round and everything stops.
no case seperations, just a stuck case. this has happened with new barrels.
what i noticed was a significant dent/gouge in the brass from the barrel's feed ramp center ridge. on some barrels like the Kriegers and Criterions, this needs attention as that point between the two feed ramp cuts damages and deforms the brass enough to cause an issue.
remember, commercial brass is softer/thinner than the military spec brass.... case expansion is drastically different and so there are two different headspace parameters for 7.62x51 milspec vs .308 sammi spec commercial ammo.
point is , expansion is rapid with commercial brass and anything impeding extraction, such as a dent/defromation in the case wall , foreign object in chamber ect, can cause brass to get stuck in the chamber. The violent extraction of an M14 type action is hard on good brass, let alone poor quality, deformed brass.

when the neck seperation happened in that SAK barrelled match rifle, the rear half of the case was almost identical in length as a 45 acp case.... maybe a millimeter or two longer. the neck section...... I may still have it somewhere..... looks just like driller's pic.
In my rifle i tried to chamber the rifle 4 or 5 times after the initial stoppage. the bolt looked closed from the operators position behind the sights.
4 or 5 times i could have experienced what Driller possibly has....... i got lucky i think :D

it's just my opinion but from the posts and pics...... slam fire on a not quite closed bolt.
an out of battery would have blown the mag out the bottom, or at least that is what is designed to happen.
 
damn. well there goes that. I guess a few of my less favorite rifles will have to go so I can get a new m14... got any extras kicking around there Doc? :p
 
45ACPKING said:
expansion is rapid with commercial brass and anything impeding extraction, such as a dent/defromation in the case wall
Click to expand...

Would a deformation in the case wall be easy to detect by looking at the ejected brass? I've never seen this before, but I'm guessing you mean the chamber is crooked so the brass is flowing into a channel and straightens out on extraction?
 
Rocket Surgery said:
Would a deformation in the case wall be easy to detect by looking at the ejected brass? I've never seen this before, but I'm guessing you mean the chamber is crooked so the brass is flowing into a channel and straightens out on extraction?
Click to expand...

nope, nothing to do with chamber dimension or trueness ect.
take your rifle and a dummy round and slide the round forward from the mag into the chamber. observing where the case starts to make contact with the feed ramps.

the m14 has two feed ramps that come together to form a point almost. This "point" on "some" barrels is rather sharp , more often on new barrels and on every krieger and criterion i have installed to date. As the round enters the feed ramps from the mag, "on some rifles", I have observed denting , near the datum and mid case. I inspect every piece of brass from a newly built rifle, looking for signs of pressure, extractor issues, primer behavior ect.

the one time this stuck neck in chamber scenario happened to me, I could not place the culprit but never used AE ammo again and the problem never repeated.
In the LRB/Krieger /USGI build I did for I <3 M14 a few months back, the rifle was seriously damaging the case while chambering. this led to a failed extraction with the action cycling back and the empty case in the chamber.
lucky i test fire 1 round mags, then 2 round mags for the test and break in.

this case showed no adverse signs other than the gouging from the feed ramp "point". once this was detailed and not so pointy, the brass looked as it should and no more gouges/dents in the brass.

I am not saying this is what caused driller's case seperation, just sharing an experience and my conclusions on that episode I experienced.
 
I was reading Jerry Teo's article on m1a reloading and he starts getting into ####-eyed chambers etc etc, have you seen a lot of this? I'm just curious. If your chamber looks ribbed for her pleasure, is that something you can normally polish out?
 
That's crazy. I once had a slam and head sep in my rifle. Didn't get that kind of damage.

What kind of ammo was it ?

And, is it just me, or does that machine look a bit over lubricated ?

You seriously have only put 300 rounds thru it since you got it ?
How many times was it cleaned ?
 
Wow, I'm glad that nobody got hurt in this one. I cannot even make a call on this one... it's out of my experience set. 45ACPKing knows what he is doing and he is on things right now.

Barney
 
Conte said:
That's crazy. I once had a slam and head sep in my rifle. Didn't get that kind of damage.

What kind of ammo was it ?

And, is it just me, or does that machine look a bit over lubricated ?

You seriously have only put 300 rounds thru it since you got it ?
How many times was it cleaned ?
Click to expand...

It was american eagle jacketed .308

What you are seeing on the op rod there is not actually lubricant, it is either poor machining or some sort of coating that is uneven.

I do not over lubricate as that leads to a bunch of dust and other debris getting caught in the lubricant and gumming up the rifle.
 
I had a case sep a while ago in a Norc shorty.

I am pretty sure mine came from me reusing the same brass too many times. Gonna have to start counting.(and upgrade to harder primers...)

FWIW I got the front half of the separated case out of the chamber by putting a fired case in behind it and letting the bolt ride forward about five times. The fired case was pushed pretty securely into the separated case and they both came out together.
 
Now I find out.....seems to have been a problem for a Long time.

Found this post at another forum from about 3 years back

Every where I read it says that AE has some of the softest brass around. Case separations in that exact spot are common with autos

Federal called me back this morning.

Although they know a lot of us shoot AE .308 in military semi-autos, they don't recomend AE .308 for rifles with 7.62 NATO chambers due to the thinner case walls.

I'm sending them the separated case and the rest of the unfired ammo
for their inspection.

I'll post the results if I ever hear anything back.

Flyer
Click to expand...
 
Federal pistol primers are known to be very soft, but the rifle ones are alright. I never knew AE brass has super thin walls. They make specific M1 ammo and I doubt they run their own brass, so I always thought that stuff was good for M1A. Different pressures I guess between the 7.62x63 and 7.62x51
 
It's all about the brass
A E brass has been known to cause issues in semi autos. looks like from the post above..... they admit it themselves by way of disclaimer.

I primarily test fire with federal power shok SP (the blue box) 150gr and have never had a single issue in any of the rifles i've shot it in with headspace under 1.640" (most new norcs are under this and that is good). so, i can comfortably say..... stay away from A E .... but the other federal products seem to be fine ;)
 
Is there a general rule as to how many times a brass case can be reloaded or is it ok to keep using it as long as its physically fine?

Im asking because Ive been collecting my Norinco 7.62x51 cases that were fired once and am hoping to reload someday.
 
Muttley you should take a flashlight and check to see if your cases are boxer or berdan primed. Two little holes is berdan, which makes it significantly more difficult to reload and better to sell as scrap. If there's one hole, that's boxer primed, and that's simple.

The general rule for reloading is to run the brass until it cracks at the neck. This is for bolt guns with no headspace. In guns like Enfields, if you have a case head separation, it's kind of a big deal but probably won't end up in any injuries. When you're dealing with these m305 rifles, they're designed to shoot 7.62x51, but they know people will fire 308 out of them so the chambers are cut to accept both. This makes it so you get some funky headspace, your 308win commercial brass will start to get weak around the head (near the web) but it will usually take like 6-7 firings before it actually separates in teh chamber. Keep in mind there may be a fresh cartridge about to slam into that chamber, so what happens next is up to about 58,000 PSI of propellant, a primer, and a chinese metal bolt. The general internet rule is to keep it to 4 reloads then toss the brass, or 5 with NATO spec brass.
 
This is good stuff guys I am learning a fair bit here.

Just a quick random question, what kind of head space gauge is a good one to have around? There seem to be tonnes of brands and a couple different types..
 
Rocket Surgery said:
Muttley you should take a flashlight and check to see if your cases are boxer or berdan primed. Two little holes is berdan, which makes it significantly more difficult to reload and better to sell as scrap. If there's one hole, that's boxer primed, and that's simple.

The general rule for reloading is to run the brass until it cracks at the neck. This is for bolt guns with no headspace. In guns like Enfields, if you have a case head separation, it's kind of a big deal but probably won't end up in any injuries. When you're dealing with these m305 rifles, they're designed to shoot 7.62x51, but they know people will fire 308 out of them so the chambers are cut to accept both. This makes it so you get some funky headspace, your 308win commercial brass will start to get weak around the head (near the web) but it will usually take like 6-7 firings before it actually separates in teh chamber. Keep in mind there may be a fresh cartridge about to slam into that chamber, so what happens next is up to about 58,000 PSI of propellant, a primer, and a chinese metal bolt. The general internet rule is to keep it to 4 reloads then toss the brass, or 5 with NATO spec brass.
Click to expand...

Thanks BIG TIME for this Rocket, I'm sticking to this advice seriously!
 
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