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Posted: 10/1/2011 2:40:53 PM EDT
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using my reloads which consist of once fired brass
all cases are gauged after final loading. load data 25.4 grain H335, 55gr FMJ, Wolf Primers This happened in my 5.56 upper from a very reputable company... has had thousands (3-4K) of rounds down the pipe without any issue. I only noticed the problem because the rifle jammed when trying to feed the next round. I didn't notice any extra smoke, noise, etc... What could have caused this? and what do I do with the other 1500 rounds I have loaded This first pic is lake city brass 
I don't know the head stamp of the second case 
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Oversized brass. Bumping the shoulder back too far creates excessive headspace which will cause case head separation like you experienced. on my dillon gage would it be below the shorter step then? i don't see any damage to the gun but how can I be sure I don't have a cracked chamber or something along those lines. |
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I've seen a fair number of that type of separation. It can come from the case just wearing out, or more commonly for me, from excessive headspace before I got a case gage. Excessive headspace causes the case to stretch and thin right where your separations were. Proper headspace minimizes the stretching and thinning. |
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Solution is to use a headspace tool like the one from Hornady or Sinclair. Only bump your shoulder .005" for semi or .001"-.002" for bolt.
If you are bumping the shoulder more that .008", then you are going to have excessive headspace issues. Hornady set |
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Quoted: on my dillon gage would it be below the shorter step then? i don't see any damage to the gun but how can I be sure I don't have a cracked chamber or something along those lines. Put a fired, unsized case into your dillon gage, and see where it comes to. then compare that to a sized case. The sized case should only be about .002" shorter than the unsized case in the gage. You should be able to visually inspect your chamber for a crack, but I doubt you will find one. You can use the paper clip tool (I use a small, long-shanked allen wrench) to feel the groove on the inside of the case wall. That should become a part of your case prep routine.
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Quoted:
Quoted:
Oversized brass. Bumping the shoulder back too far creates excessive headspace which will cause case head separation like you experienced. on my dillon gage would it be below the shorter step then? i don't see any damage to the gun but how can I be sure I don't have a cracked chamber or something along those lines. The problem is that headspace is different on each rifle. You will need a micrometer caliper-mounted gage to measure what your headspace is. Take a piece of once fired brass out of YOUR rifle and measure headspace. Then, only bump shoulder back .005" from that measurement. Your gun should be fine. |
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I would call those case body separations not case head separations. If you're using a Dillon case gage to check your reloads make sure that a factory round checks the same way in the case gage as well. If your reloads gage the same as factory ammo then it's your gun that has a problem not your reloading technique. |
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Here is a trick an old timer taught me. Load up a fresh primer into a .223 case that you have sized and trimmed, no powder, no bullet. Insert in your AR, close and lock the bolt. Fire. Carefully remove case and primer. Primer should protrude out from the back of the case the amount of head space, your sized case is generating in your rifle chamber. You might want to try thee or four to see if it is consistent.
[ETA] Hornady, RCBS, etc. make gages to measure the distance from a shoulder reference dia. to the surface of the case head. Check your as- fired cases (fireformed to the chamber minus .001 or .002) and compare to your sized and trimmed case. There should be only a few thousandths difference (maybe .005) between sized and as fired if everything is set up correctly. 1X LC's typically do not experience head separation on the second firing. You may find that after 3,000 down the pipe, your barrel extension lugs, bolt lugs, bolt face, etc. have worn, and need some compensation.[ETA] 1X LCs will still have the crimp ring, before case preparation for 2X. |
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so I should be checking for excessive head space right? would I only need a FIELD gauge?
http://www.brownells.com/.aspx/lid=10327/guntechdetail/Colt-5-56-223-Headspace-Gauge-for-AR-15-M16 |
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The FIELD NO-GO gage will tell you (the armorer) that the chamber is usable but is at the max dimension if it "goes". I think most ARs have the 5.56 NATO chamber, but check to be sure that is what you have.
[ETA] Darn! I always have troulbe with these gage definitions: According to Forster note on Midways Site: No-Go Gage: •Duplicates the distance over the maximum allowable, from the case head (or boltface) to the datum line of the cartridge's shoulder, allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing. •If the firearm locks up in battery when the gage is inserted, [GOES] then it is not within acceptable maximum headspace dimensions. The firearm should not be used and should be examined further by a knowledgeable gunsmith. Field Gage •Duplicates the maximum allowable distance, from the case head (or boltface) to the datum line of the cartridge's shoulder, allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing. •If the firearm locks up in battery when the gage is inserted, [GOES] then it is at the maximum acceptable headspace and should be examined further by a knowledgeable gunsmith. |
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Quoted:
so I should be checking for excessive head space right? would I only need a FIELD gauge? http://www.brownells.com/.aspx/lid=10327/guntechdetail/Colt-5-56-223-Headspace-Gauge-for-AR-15-M16 That gauge is for checking the chamber of your rifle. Your chamber can have excessive headspace or your brass may have the shoulder sized back too far. Here is a vid of how to use the gauge in your link. If the 1500 rounds you've already loaded have been sized back too far, you may be seeing a fair number of case-body/head separations. |
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Quoted:
The FIELD NO-GO gage will tell you (the armorer) that the chamber is usable but is at the max dimension if it "goes". I think most ARs have the 5.56 NATO chamber, but check to be sure that is what you have. [ETA] Darn! I always have troulbe with these gage definitions: According to Forster note on Midways Site: No-Go Gage: •Duplicates the distance over the maximum allowable, from the case head (or boltface) to the datum line of the cartridge's shoulder, allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing. •If the firearm locks up in battery when the gage is inserted, [GOES] then it is not within acceptable maximum headspace dimensions. The firearm should not be used and should be examined further by a knowledgeable gunsmith. Field Gage •Duplicates the maximum allowable distance, from the case head (or boltface) to the datum line of the cartridge's shoulder, allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing. •If the firearm locks up in battery when the gage is inserted, [GOES] then it is at the maximum acceptable headspace and should be examined further by a knowledgeable gunsmith. Kind of confusing because the instructions for the Colt 5.56 "Field" Gauge in the OP's link says the following: "If the bolt DOES NOT cam into the locked position, the rifle does not have excessive headspace. Remember, the Bolt should NOT close on a field gauge." Guess the terms aren't interchangeable between brands??? |
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using my reloads which consist of once fired brass all cases are gauged after final loading. load data 25.4 grain H335, 55gr FMJ, Wolf Primers This happened in my 5.56 upper from a very reputable company... has had thousands (3-4K) of rounds down the pipe without any issue. I only noticed the problem because the rifle jammed when trying to feed the next round. I didn't notice any extra smoke, noise, etc... What could have caused this? and what do I do with the other 1500 rounds I have loaded This first pic is lake city brass http://i284.photobucket.com/albums/ll12/rangewarrior123/case1.jpg I don't know the head stamp of the second case http://i284.photobucket.com/albums/ll12/rangewarrior123/case2.jpg I have had around 50 to 75 of those happen with LC brass after about 5X firing. Makes a nice blast coming out of the ejection port.  All that was left went into the recycle box. I bought `em once fired. Hate the flame that shoots out of the side of the rifle when stuff like that happens.
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Not a case head separation, just a broken case, not a huge deal, I have seen it happen on RARE occasion, at least one time it was on brass that had only been reloaded ONE TIME. It happens, as long as its rare, its no big deal, but 2 in one day, you need to check some things, find out if this was just happenstance or a symptom of something wrong. This is why they make broken case extractors, although the very few I've seen never required any kind of tool to remove the broken front end, its possible, therefore I carry one in the stock storage compartment. I think I've had 2 or 3 in 10 to 15,000 rounds of 223, never had it happen in any other caliber, but I never loaded those kind of quantities in any other rifle caliber. |
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Quoted: Not a case head separation, just a broken case, not a huge deal, I have seen it happen on RARE occasion, at least one time it was on brass that had only been reloaded ONE TIME. It happens, as long as its rare, its no big deal, but 2 in one day, you need to check some things, find out if this was just happenstance or a symptom of something wrong. This is why they make broken case extractors, although the very few I've seen never required any kind of tool to remove the broken front end, its possible, therefore I carry one in the stock storage compartment. I think I've had 2 or 3 in 10 to 15,000 rounds of 223, never had it happen in any other caliber, but I never loaded those kind of quantities in any other rifle caliber. +1 Too high for a head separation. |
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Don't confuse the field gage with a case gage. As described above the field gage checks to see if your rifle's chamber is in spec. A case gage checks if a round is in spec for a in spec chamber. What causes case body separation? The case stretched too much. Could be due to out of spec gun chamber or the brass has been oversized (making it shorter from head to shoulder) which increases head space which allows the brass to stretch more than it should when fired |
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I don't think chamber headspace gages are what you need. I'd get a case comparator so you can measure how much you are sizing your fired brass. Where do you get your brass from? Are you positive it's once fired? Look carefully at the dings around the rim. That may tell you otherwise. |
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You have a case seperation in the body from excessive Full Length sizing of the brass. A defective Dillon shell plate caused mine. Good Info> Put a fired, unsized case into your dillon gage, and see where it comes to. then compare that to a sized case. The sized case should only be about .002" shorter than the unsized case in the gage. http://i338.photobucket.com/albums/n420/joe1944usa/caseseparation.jpg http://i338.photobucket.com/albums/n420/joe1944usa/IMG_2902DILL.jpg
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I know this is expensive, but this guy's gauge has been a God send to me.
Digital Headspace Gauge Knock on wood, so far, no kabooms or separations. You adjust the gauge to mid shoulder of an unsized case, and than size it. After sizing it, you put it back in the gauge, and see how far you bumped it back. Than readjust your die to where you are not oversizing them. ETA: For the record, I have no affiliation with this business. http://www.larrywillis.com/mainpage.html 
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| thanks for all the replies... what i don't understand is how it would be a sizing issue since I check the sized cases using a case gauge and all is within spec. This die setting has not changed in a long time and this is the first issue I have had. I've ordered a head space gauge to see if there is any head space issue , I'll keep this post updated with new info |
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Head separation versus body separation. WTF?
They both happen for the same reason. The case stretches and thins and then separates. The point where this occurs is about where the web finally thins to the nominal wall thickness as that is where the case remains "stuck" under pressure while the head moves aft during firing. The only difference is where this occurs on a given cartridge and on the .223 it is a lot farther up the case than on, for example, a .308. ––––- Mil-surp brass is often fired in machine guns where the headspace increases over time. This has been a big issue with non match 7.62x51 brass, and the same issue can show up in 5.56mm brass. The difference is that while most non match 7.62x51 brass was probably fired in an MG, the percentage of 5.56mm brass fired in an MG (as opposed to an M4 or M16 variant) is smaller. ––––- I would not sweat 1-2 cases out of a batch of surplus brass. The AR-15 handles head separation well and if the chamber and brass are fairly clean the front of the case will also be ejected. If it becomes a regular thing, than excessive headspace over sizing may be an issue. |
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If its only LC brass doing this > Quality control will treat brass in a chemical to age the brass fast. This may make it brittle? LC brass sold as scrap might have this porblem? The approximate shelf life of the ammunition is also tested here. "We place the ammunition in a chemical solution. This process allows for the brass imperfections to be easily identified" said Ojeda. "Any potential defects in the brass will become more apparent due to the reaction of the solution. Theoretically, the test makes it possible to identify flaws in the brass that under normal conditions, could only be noticed after a lengthy period of time."
Read the whole article here > http://www.army.mil/article/11859/ Never let ammonia or vinegar come in contact with brass. http://<ahttp://i338.photobucket.com/albums/n420/joe1944usa/th_223LC86Brittle_002.jpg</a>" /> More reloading photos here> http://www.photobucket.com/joe1944usa
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Quoted:
The FIELD NO-GO gage will tell you (the armorer) that the chamber is usable but is at the max dimension if it "goes". I think most ARs have the 5.56 NATO chamber, but check to be sure that is what you have. [ETA] Darn! I always have troulbe with these gage definitions: According to Forster note on Midways Site: No-Go Gage: •Duplicates the distance over the maximum allowable, from the case head (or boltface) to the datum line of the cartridge's shoulder, allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing. •If the firearm locks up in battery when the gage is inserted, [GOES] then it is not within acceptable maximum headspace dimensions. The firearm should not be used and should be examined further by a knowledgeable gunsmith. Field Gage •Duplicates the maximum allowable distance, from the case head (or boltface) to the datum line of the cartridge's shoulder, allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing. •If the firearm locks up in battery when the gage is inserted, [GOES] then it is at the maximum acceptable headspace and should be examined further by a knowledgeable gunsmith. Thanks for posting thee quote above from Midway: http://www.midwayusa.com/Product/383456/forster-headspace-gage-field-length-223-remingtonUnfortunately Midway is incorrect. Here is what Forster says: Forster offers three lengths of headspace gages per rifle caliber. In order from the shortest to longest, they are: GO, NO-GO and FIELD: GO: Corresponds to the minimum chamber dimensions. If a rifle closes on a GO gage, the chamber will accept ammunition that is made to SAAMI’s maximum specifications. The GO gage is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gage is necessary for a gunsmith or armorer, it usually has fewer applications for the collector or surplus firearms purchaser. NO-GO: Corresponds to the maximum headspace recommended for gunsmiths chambering new firearms. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gage, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gage. The NO-GO gage is essential for checking a newly-reamed chamber in order to ensure a tight and accurate chamber. FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gage, its chamber is dangerously close to, or longer than, SAAMI’s specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gages are slightly shorter than the SAAMI maximum in order to give a small safety margin. http://www.forsterproducts.com/store.asp?pid=24834 A shooter checking for unsafe headspace in his rifle needs to use the FIELD gauge. If the stripped bolt closes on the Field gauge, then the rifle is unsafe to fire. |
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Quoted:
Quoted:
The FIELD NO-GO gage will tell you (the armorer) that the chamber is usable but is at the max dimension if it "goes". I think most ARs have the 5.56 NATO chamber, but check to be sure that is what you have. [ETA] Darn! I always have troulbe with these gage definitions: According to Forster note on Midways Site: No-Go Gage: •Duplicates the distance over the maximum allowable, from the case head (or boltface) to the datum line of the cartridge's shoulder, allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing. •If the firearm locks up in battery when the gage is inserted, [GOES] then it is not within acceptable maximum headspace dimensions. The firearm should not be used and should be examined further by a knowledgeable gunsmith. Field Gage •Duplicates the maximum allowable distance, from the case head (or boltface) to the datum line of the cartridge's shoulder, allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing. •If the firearm locks up in battery when the gage is inserted, [GOES] then it is at the maximum acceptable headspace and should be examined further by a knowledgeable gunsmith. Thanks for posting thee quote above from Midway: http://www.midwayusa.com/Product/383456/forster-headspace-gage-field-length-223-remingtonUnfortunately Midway is incorrect. Here is what Forster says: Forster offers three lengths of headspace gages per rifle caliber. In order from the shortest to longest, they are: GO, NO-GO and FIELD: GO: Corresponds to the minimum chamber dimensions. If a rifle closes on a GO gage, the chamber will accept ammunition that is made to SAAMI’s maximum specifications. The GO gage is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gage is necessary for a gunsmith or armorer, it usually has fewer applications for the collector or surplus firearms purchaser. NO-GO: Corresponds to the maximum headspace recommended for gunsmiths chambering new firearms. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gage, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gage. The NO-GO gage is essential for checking a newly-reamed chamber in order to ensure a tight and accurate chamber. FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gage, its chamber is dangerously close to, or longer than, SAAMI’s specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gages are slightly shorter than the SAAMI maximum in order to give a small safety margin. http://www.forsterproducts.com/store.asp?pid=24834 A shooter checking for unsafe headspace in his rifle needs to use the FIELD gauge. If the stripped bolt closes on the Field gauge, then the rifle is unsafe to fire. I read the same thing for the Forster and Midway definition, both say field represents the maximum allowable head space and the rifle should be checked if the field gauge chambers, not that the chamber is over max and unsafe to use. There is .010" between min and max head space which is the difference between a go gauge and a field gauge, these gauges only tell you which end of the spectrum your chamber is on but tell you nothing in between which is why a gauge like the Hornady head space gauge should be used, because it doesn't matter where on the scale your chamber falls(as long as it's not over field) as long as the brass is properly sized to fit it. |
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I know this is expensive, but this guy's gauge has been a God send to me. Digital Headspace Gauge Knock on wood, so far, no kabooms or separations. You adjust the gauge to mid shoulder of an unsized case, and than size it. After sizing it, you put it back in the gauge, and see how far you bumped it back. Than readjust your die to where you are not oversizing them. ETA: For the record, I have no affiliation with this business. http://www.larrywillis.com/mainpage.html http://www.larrywillis.com/COAD-06.jpg I also use one of the innovative gauges, they work great |
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Quoted: I think both of those two separations that happened at the neck may have been due to a bit of overzealous neck trimming. If you trim too short, you are faced with donuts, but if you over trim, you cut into the shoulder too much and this thin it to the extent that will cause exactly what you see here.
If its only LC brass doing this > Quality control will treat brass in a chemical to age the brass fast. This may make it brittle? LC brass sold as scrap might have this porblem? The approximate shelf life of the ammunition is also tested here. "We place the ammunition in a chemical solution. This process allows for the brass imperfections to be easily identified" said Ojeda. "Any potential defects in the brass will become more apparent due to the reaction of the solution. Theoretically, the test makes it possible to identify flaws in the brass that under normal conditions, could only be noticed after a lengthy period of time." Read the whole article here > http://www.army.mil/article/11859/ Never let ammonia or vinegar come in contact with brass. http://<a href=http://i338.photobucket.com/albums/n420/joe1944usa/th_223LC86Brittle_002.jpg</a>" /> More reloading photos here> http://www.photobucket.com/joe1944usa |
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I think both of those two separations that happened at the neck may have been due to a bit of overzealous neck trimming. If you trim too short, you are faced with donuts, but if you over trim, you cut into the shoulder too much and this thin it to the extent that will cause exactly what you see here ]. Sorry, Wrong.  Cutting into the shoulder would be during outside neck turning, not trimming. The brass had become brittle and broke on firing or resizing. Annealing will not correct this. Brass was left in a cleaning solution to long by mistake.. A mixture containing vinegar, that can cause dezincification of brass. Donuts are formed when sizing necks up or down to a different caliber. The shoulder movers into the neck area. Here is the photo full size, you can see its brittle & cracked. http://i338.photobucket.com/albums/n420/joe1944usa/223LC86Brittle_002.jpg
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Quoted: I think both of those two separations that happened at the neck may have been due to a bit of overzealous neck trimming. If you trim too short, you are faced with donuts, but if you over trim, you cut into the shoulder too much and this thin it to the extent that will cause exactly what you see here ]. Sorry, Wrong. Cutting into the shoulder would be during outside neck turning, not trimming. The brass had become brittle and broke on firing or resizing. Annealing will not correct this. Brass was left in a cleaning solution to long by mistake.. A mixture containing vinegar, that can cause dezincification of brass. Donuts are formed when sizing necks up or down to a different caliber. The shoulder movers into the neck area. Here is the photo full size, you can see its brittle & cracked. http://i338.photobucket.com/albums/n420/joe1944usa/223LC86Brittle_002.jpgMy mistake, I did mean neck turning of course - should be obvious from my description.... Been trimming and turning so much I get them mixed up! So are these your brass? The fact is neck turning can also weaken the brass in this area which would may also cause cracks. |
| Could excessive gas port pressure or volume cause something like this? Could this be a timing issue? Is it possible for the bolt to start the unlocking and extraction process while the chamber pressure is too high, causing the back of the case to be extracted while the front part of the case is pressed hard against the chamber walls by the high pressure? |
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I had this happen to me the other day also, my brass looked exactly like the OP's. It was 1x fired LC '09 brass, was also first fired in the same rifle, Savage VLP, bolt action. This is my mid-range F-class rifle and I load the .223 hot. I push a 75gr A-max at or near 3000fps w/H4895. Now when it happened the round went off fine, case came apart on extraction.
This has never happened before on only the 2nd firing, I usually see this after 3 or 4 firings on LC brass. On this firing I was using TAC as an experiment. SY |
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