View Full Version : Torn Case
Jay Cunningham
03-17-10, 15:37
Was tweaking the zero on my SBR today and had what I thought was a failure to eject. After screwing around it became clear that something was preventing rounds from entering the chamber. I looked around and sure enough found the ass-end of a case and then found the front. Fortunately I had a CJ Weapons Broken Shell Extractor in my bag and finally got a chance to use it. It worked perfectly! Good thing too, because it would have shut me down otherwise.
http://i288.photobucket.com/albums/ll200/Thekatar/torncase.jpg
I am going to buy another one of these and keep it on my "serious" AR while the other one can stay in my range bag.
(I was shooting reloaded m855 green tip, BTW...)
How did the case break like that?
Jay Cunningham
03-17-10, 15:40
Just one of those things. Must have been a piece of brass that got reloaded one too many times or was slightly out of spec. An 11.5" SBR has a relatively violent extraction but I am using an H2 buffer and I am *not* using an extractor O-ring, so it shouldn't be too brutal.
It could also be a tight chamber, but it is a BCM so I doubt that is the reason. It's possible, though. We'll see down the road if it happens again.
Seen often...with predictability...in certain reloads using "once fired" brass that isn't.
Pretty nasty. Good thing you had the ruptured case extractor. Every range kit should have one.
Failure2Stop
03-17-10, 16:16
There is a good probability of this happening if the reloads are made from SAW (M249) brass.
ForTehNguyen
03-17-10, 16:19
something to do with the SAW belt links making that part of the case weaker than the rest?
something to do with the SAW belt links making that part of the case weaker than the rest?
Someone here has to have the answer to that question. I know it's not the links though, I think it has something to do with the extraction process. I remember reading briefly somewhere that the brass gets stretched some how. I just don't remember how, or why.
Anyway care to fill us in?
Pretty nasty. Good thing you had the ruptured case extractor. Every range kit should have one.
I've had this happen on a bench gun and found that sticking a tight fitting bronze brush up into the case did the trick. Luckily I had my cleaning kit with a bunch of different brushes.
David Thomas
03-17-10, 17:33
had this happen in a 1911
https://www.m4carbine.net/showthread.php?t=4913&highlight=failure
Failure2Stop
03-17-10, 17:38
something to do with the SAW belt links making that part of the case weaker than the rest?
It has something to do with the cycle of function specific to the weapon. I have heard different theories, but nothing beyond what I consider to be speculation.
Belmont31R
03-17-10, 19:30
Ive only had that happen once, and it was with Black Hills blue box 69 SMK's. Just brass that has been shot too much, and can happen with reloads.
decodeddiesel
03-18-10, 11:45
Need to get one of those broken case extractors.
I heard that it had something to do with the weapon firing from the open bolt position (rounds slamming into the breech) and then extracting so fast due to the rate of fire.
It has something to do with the cycle of function specific to the weapon. I have heard different theories, but nothing beyond what I consider to be speculation.
Jay Cunningham
03-18-10, 12:03
That is pretty interesting, I've never heard it before.
I had one stuck case down at BW a few weeks back that I was able to clear by mortaring the gun. This was an LE6920, so I assume the overall operation of the gun (compared to an 11.5") was mild enough that it tried and failed to pull out the case, vs. trying and ripping it in half.
Blankwaffe
03-19-10, 02:13
I heard that it had something to do with the weapon firing from the open bolt position (rounds slamming into the breech) and then extracting so fast due to the rate of fire.
I was told that the cartridge cases that had been fired through a SAW would not be acceptable for reloads due to the fact that headspace specification of that weapon caused excessive stretch in the web of the case as compared to the M16 series.Once resized the brass at times will clearly indicate a ringed web on the exterior.
It was recommended to inspect all the military spent cases inside and out for a ringed web,particularly after resize.High tech tool indicated to use at the time was a straightened paper clip to check the inside web of the case when going through bulk surplus brass..
Other warning was to look for deformed cartridge case rims.
Guess how many buttstocks I replaced in the last week due to personnel incorrectly "mortaring" their weapons.
That is pretty interesting, I've never heard it before.
I had one stuck case down at BW a few weeks back that I was able to clear by mortaring the gun. This was an LE6920, so I assume the overall operation of the gun (compared to an 11.5") was mild enough that it tried and failed to pull out the case, vs. trying and ripping it in half.
There is a good probability of this happening if the reloads are made from SAW (M249) brass.
Most likely...
http://www.dtic.mil/ndia/2006smallarms/fischer.pdf
Note longitudinal stretching/head space...worn , out of spec M249s - not uncommon
There's a little more to it, but here's something for those interested to research.
Seen this often before...
Guess how many buttstocks I replaced in the last week due to personnel incorrectly "mortaring" their weapons.
never had to do this...can I get an explanation or link to do it correctly sir??
Heavy Metal
03-19-10, 09:11
The condition you are looking for is called incipient case head seperation.
The best check is to straighten a paperclip and bend about a 3mm long section 90 degrees to the tip and run it inside the case feeling for the ring.
And I would bet that was SAW brass.
Jay Cunningham
03-19-10, 09:34
never had to do this...can I get an explanation or link to do it correctly sir??
If you have a collapsing stock, you collapse it all the way. You hold the rifle straight up and down in your support hand, with your strong hand on the charging handle. You bring the rifle straight down to the ground on the buttstock simultaneously pulling the charging handle.
This is your best bet to clear a stuck case that the extractor is sill holding onto. Works a fair amount of the time.
3. All because someone either demonstrated the technique incorrectly or they didn't get the memo.
ill bite. how many?
decodeddiesel
03-19-10, 12:42
Always always always collapse your stock in all the way before mortaring. Then you want a nice square strike to the deck.
Sounds easy, but it's just as easy to **** up.
never had to do this...can I get an explanation or link to do it correctly sir??
From another thread:
Originally Posted by dbrowne1
Used to clear a stuck round or casing. You kneel down and hold the rifle vertically with the stock toward the ground, holding the foreend with your left hand. Close the bolt over the stuck case/round and then slam, or "mortar" the rifle onto the ground while holding open the release latch on the charging handle. It generates a sudden "jerk" on the bolt that can help pull the stuck case/cartridge out.
Originally Posted by Gutshot John
Make sure you collapse your stock all the way first.
Originally Posted by Luke_Y
Also, take care to strike the stock squarely. There is a tendency to strike on the toe resulting in breaking off the toe on standard m4 stocks.
And, be very muzzle aware...
ETA Oops, I could have clicked through to pg2 to see that it was already answered- instead of the cut and paste. :)
Glad to see the extractor worked so well. I keep one in the 3 round core of my MIAD grip, along with a derlin pin punch and a A2 front site tool.
The problem could have also been a weak extractor spring. In each of the weapons that I examined there was another common theme- LACK OF LUBRICATION. Someone has convinced some of these guys that lube is bad in the desert because of the dust.
Glad to see the extractor worked so well. I keep one in the 3 round core of my MIAD grip, along with a derlin pin punch and a A2 front site tool.
PoconoChris
03-19-10, 15:38
For anyone looking for the broken shell extractor, here is the website. They are only $10.
http://www.cjweapons.com/aspcart45/default.asp?page=307&start=1
"if you don't scrub the chamber with solvent and a brush every 200 rounds then you will get torn cases and broken extractors.":p
Its a joke from this thread
https://www.m4carbine.net/showthread.php?t=49796
3. All because someone either demonstrated the technique incorrectly or they didn't get the memo.
Sounds like a bigger issue for that many shooters to be needing to mortar rounds out. :confused:
Someone has convinced some of these guys that lube is bad in the desert because of the dust.
hahahahahhahahaha
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