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Posted: 4/30/2014 3:44:07 PM EDT
OVERVIEW
SIDE VIEW 
PRIMER END 
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The Load -
30 gr Barnes Varmint Grenade OAL = 2.090" Light crimp using Lee Factory Crimp Die Winchester case - new or once fired, not old or stretched, full length sized to about 0.003" smaller than chamber 26.5 gr TAC Winchester Small Rifle primer The Rifle - was a Rock River ARMS 16" carbine upper, relatively new (<1,000 rounds fired). I have no reason to suspect anything was wrong with the rifle. Prior to testing these rounds, it has performed flawlessly. The Scenario - I was shooting from a bench, testing this load for function and velocity over a chronograph. Ten rounds were loaded into the magazine. The rounds would fire but none properly cycled the action. There was one failure to eject, every one failed to feed the next round. The failure to feed meant I was manually cycling the action to feed successive rounds. After manually retracting the charging handle then releasing it to let the bolt fly home, the cartridge fired before the bolt closed. The event was energetic but I was not injured in any way but more than a bit surprised, humbled and puzzled. The rifle was unaffected. Additional Information - There was some evidence of unburned powder in the rifle. Whether this was from previous cartridges or from this slam-fired cartridge, I do not know. It looks as if it fired before the cartridge even straightened out on the feed ramps. |
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There was speculation there was debris, possibly unburned powder, on the bolt face which contacted the primer and caused the cartridge to fire.
I am going to disassemble all the remaining rounds. The combination of a super-light bullet and a relatively slow burning powder and a short-barreled carbine do not look like a good mix. |
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Quoted:
Out of battery fire with no injury or damage to rifle, thank goodness, you just got a second birthday to celebrate. Indeed!, and thank you. What puzzles me is the circular "ejector mark" on the edge of the primer. Normally, the ejector touches the rim of the case head not the primer. Why was the case sitting on the ejector when it fired? It seems to have failed to engage the bolt face and extractor? Was it sitting on top of the ejector and lugs. Was this improper feeding what caused it to fire too soon? The case got pushed back onto the bolt face at some point, because the primer cup got extruded into the firing pin hole and there are fairly deep extractor marks on the rim. |
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Quoted:
i am not a fan of using TAC with sub 55gr. bullets had some problems a few years ago. i now use exterminator for the lighter stuff. I am no longer a fan, either. 
It was listed in the Barnes load for the 36 gr bullet, so I tried it with the 30 grainer - never again! I'm pulling bullets tonight. |
| I'm wondering if the very short OAL, caused by the super-light bullet, allowed improper feeding in the receiver. If the cartridge could fit in places a normal cartridge could not, that may have resulted in it sitting in front of the lugs (on the lugs) rather than in the bolt face. |
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Quoted:
OVERVIEW http://www.hunt101.com/data/500/medium/024102.JPG SIDE VIEW http://www.hunt101.com/data/500/medium/03067.JPG PRIMER END http://www.hunt101.com/data/500/medium/029a.jpg SOBERING Glad you are OK. Go buy a lottery ticket. Thanks for posting, I might just print this pic up and tack it to my supply cabinet as a reminder. |
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First off, glad you weren't injured.
I had a similar thing happen to me a few years ago. The fired case looked almost exactly like yours except mine was cut cleanly in half like it was done with a saw and the front half of the case was stuck in the chamber. I eventually came to the conclusion that my problem was a sizing issue. ETA: My primer didn't look anything like yours does. Mine looked just fine and I don't recall my case having the same bulge near the base as yours does. |
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Quoted:
First off, glad you weren't injured. I had a similar thing happen to me a few years ago. The fired case looked almost exactly like yours except mine was cut cleanly in half like it was done with a saw and the front half of the case was stuck in the chamber. I eventually came to the conclusion that my problem was a sizing issue. ETA: My primer didn't look anything like yours does. Mine looked just fine and I don't recall my case having the same bulge near the base as yours does. Yes, exactly the same here, I'd forgotten that bit. The front half of the case was stuck in the chamber. I "extracted" it using a brass bristle brush on a pistol cleaning rod.
bm3 said the same thing, above. In what way was it a sizing issue, or what aspect of your case sizing did you change as a result? I do plan to gage some unfired rounds and see how they compare to some fired cases. If it's a sizing thing, I need to know. |
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As it may have been OOB, check the chamber because that was a mighty big jump between the case and the lands of the barrel. If at all possible i would do a wax and trace on it to inspect for damage or deformation.
ETA: to define wax and trace its a industrial grade impression wax commonly used in precision machining. i sugested it over slugging as to focus on the neck of the chamber. |
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Quoted:
As it may have been OOB, check the chamber because that was a mighty big jump between the case and the lands of the barrel. If at all possible i would do a wax and trace on it to inspect for damage or deformation. ETA: to define wax and trace its a industrial grade impression wax commonly used in precision machining. i sugested it over slugging as to focus on the neck of the chamber. Any wax in particular your recommend? Never heard of it before but it sounds like another method to 'cast' a chamber for those of us who can't set up a melting pot for cerrosafe. Thanks Eric |
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Any wax in particular your recommend? Never heard of it before but it sounds like another method to 'cast' a chamber for those of us who can't set up a melting pot for cerrosafe. Thanks Eric Quoted:
Quoted:
As it may have been OOB, check the chamber because that was a mighty big jump between the case and the lands of the barrel. If at all possible i would do a wax and trace on it to inspect for damage or deformation. ETA: to define wax and trace its a industrial grade impression wax commonly used in precision machining. i sugested it over slugging as to focus on the neck of the chamber. Any wax in particular your recommend? Never heard of it before but it sounds like another method to 'cast' a chamber for those of us who can't set up a melting pot for cerrosafe. Thanks Eric Kerr impression compound. Red sticks. Working temp is 132-133F and can be easily melted, blocked and set. It doesn't deform and is advertised for dental but it's used to trace cmm impressions in the aircraft industry to measure difficult radius' you can cast a chamber by using a graphite case lube like one shot. and plugging with anything from clay or play doh. Pour the wax in and let it cool and tap the clay pluged in to pop out the impression. If any of the wax sticks or breaks you can easily scrape it out or melt it out. Just remember to lube areas the have a lot of surface tension so the wax doesn't adhear to a 360deg area like a chamber. Otherwise you'll be chipping it out. |
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Quoted:
I am no longer a fan, either.
It was listed in the Barnes load for the 36 gr bullet, so I tried it with the 30 grainer - never again! I'm pulling bullets tonight. Quoted:
Quoted:
i am not a fan of using TAC with sub 55gr. bullets had some problems a few years ago. i now use exterminator for the lighter stuff. I am no longer a fan, either.
It was listed in the Barnes load for the 36 gr bullet, so I tried it with the 30 grainer - never again! I'm pulling bullets tonight. 26.5 gr TAC Actually Barnes data shows a Minimum of 27.5gr of TAC with the 36gr Bullet. Your load is a full grain less than Minimum with a lighter bullet by 6 grains. I would suspect this well below Minimum load is the reason for your unburned powder that may have clogged up the chamber causing feeding issues. Another good reason to never go below Minimum published charge weights. http://www.barnesbullets.com/wp-content/uploads/2008/01/223RemingtonWeb.pdf |
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Quoted:
The Load - .,... The rounds would fire but none properly cycled the action. There was one failure to eject, every one failed to feed the next round. The failure to feed meant I was manually cycling the action to feed successive rounds. After manually retracting the charging handle then releasing it to let the bolt fly home, the cartridge fired before the bolt closed. The event was energetic but I was not injured in any way but more than a bit surprised, humbled and puzzled. The rifle was unaffected. Additional Information - There was some evidence of unburned powder in the rifle. Whether this was from previous cartridges or from this slam-fired cartridge, I do not know. It looks as if it fired before the cartridge even straightened out on the feed ramps. The unburnt powder, lack of cycling and under minimum charge with a light bullet tells me you were probably not getting incomplete ignition. Unburnt powder built up on the shoulder of the chamber stopping the cartridge from fully seating into battery. When the bolt slammed home the case head was in a position for the primer (win= relatively soft) to make contact with the ejector inducing a slam fire. I have seen similar situations with unburnt powder while trying to develop subsonic loads using ball powders. Basically there wasn't enough pressure to ignite the full charge before the bullet left the case. Also, there wasn't enough pressure to fully expand the case to get a good seal in the camber allowing unburnt powder to be blown back into the chamber. After 2 or 3 shots enough powder built up on the shoulders of the chamber to induce a stoppage. Fortunately I caught it before I had any major problems. That's my hypothesis based on the evidence at hand. Glad you are OK. |
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Quoted:
The unburnt powder, lack of cycling and under minimum charge with a light bullet tells me you were probably not getting incomplete ignition. Unburnt powder built up on the shoulder of the chamber stopping the cartridge from fully seating into battery. When the bolt slammed home the case head was in a position for the primer (win= relatively soft) to make contact with the ejector inducing a slam fire. I have seen similar situations with unburnt powder while trying to develop subsonic loads using ball powders. Basically there wasn't enough pressure to ignite the full charge before the bullet left the case. Also, there wasn't enough pressure to fully expand the case to get a good seal in the camber allowing unburnt powder to be blown back into the chamber. After 2 or 3 shots enough powder built up on the shoulders of the chamber to induce a stoppage. Fortunately I caught it before I had any major problems. That's my hypothesis based on the evidence at hand. Glad you are OK. Quoted:
Quoted:
The Load - .,... The rounds would fire but none properly cycled the action. There was one failure to eject, every one failed to feed the next round. The failure to feed meant I was manually cycling the action to feed successive rounds. After manually retracting the charging handle then releasing it to let the bolt fly home, the cartridge fired before the bolt closed. The event was energetic but I was not injured in any way but more than a bit surprised, humbled and puzzled. The rifle was unaffected. Additional Information - There was some evidence of unburned powder in the rifle. Whether this was from previous cartridges or from this slam-fired cartridge, I do not know. It looks as if it fired before the cartridge even straightened out on the feed ramps. The unburnt powder, lack of cycling and under minimum charge with a light bullet tells me you were probably not getting incomplete ignition. Unburnt powder built up on the shoulder of the chamber stopping the cartridge from fully seating into battery. When the bolt slammed home the case head was in a position for the primer (win= relatively soft) to make contact with the ejector inducing a slam fire. I have seen similar situations with unburnt powder while trying to develop subsonic loads using ball powders. Basically there wasn't enough pressure to ignite the full charge before the bullet left the case. Also, there wasn't enough pressure to fully expand the case to get a good seal in the camber allowing unburnt powder to be blown back into the chamber. After 2 or 3 shots enough powder built up on the shoulders of the chamber to induce a stoppage. Fortunately I caught it before I had any major problems. That's my hypothesis based on the evidence at hand. Glad you are OK. I agree, it was not the choice of powder(Tac) it was the lack of powder. |
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You guys have made some very insightful posts. I think you have it exactly right - what happened and what to do about it.
Thanks to you all. In all my years of reloading, I have never before done anything like this and hope to never do it again. I think my search for a super-low recoil load will take me in the direction of a 22rimfire upper, instead of these projectiles. |
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Quoted:
Yes, exactly the same here, I'd forgotten that bit. The front half of the case was stuck in the chamber. I "extracted" it using a brass bristle brush on a pistol cleaning rod.
bm3 said the same thing, above. In what way was it a sizing issue, or what aspect of your case sizing did you change as a result? I do plan to gage some unfired rounds and see how they compare to some fired cases. If it's a sizing thing, I need to know. Quoted:
Quoted:
First off, glad you weren't injured. I had a similar thing happen to me a few years ago. The fired case looked almost exactly like yours except mine was cut cleanly in half like it was done with a saw and the front half of the case was stuck in the chamber. I eventually came to the conclusion that my problem was a sizing issue. ETA: My primer didn't look anything like yours does. Mine looked just fine and I don't recall my case having the same bulge near the base as yours does. Yes, exactly the same here, I'd forgotten that bit. The front half of the case was stuck in the chamber. I "extracted" it using a brass bristle brush on a pistol cleaning rod.
bm3 said the same thing, above. In what way was it a sizing issue, or what aspect of your case sizing did you change as a result? I do plan to gage some unfired rounds and see how they compare to some fired cases. If it's a sizing thing, I need to know. Sorry it's taken me so long to respond. I think my problem was I had two shell holders that were different thicknesses. I didn't realize that they weren't the same thickness. I was using them interchangeably and in turn it was causing the case to not get sized correctly. At least that's what I think happened. Once we were able to determine there was difference in thickness and I started using only one shell holder the problem went away. |
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Quoted:
Sorry it's taken me so long to respond. I think my problem was I had two shell holders that were different thicknesses. I didn't realize that they weren't the same thickness. I was using them interchangeably and in turn it was causing the case to not get sized correctly. At least that's what I think happened. Once we were able to determine there was difference in thickness and I started using only one shell holder the problem went away. Quoted:
Quoted:
... bm3 said the same thing, above. In what way was it a sizing issue, or what aspect of your case sizing did you change as a result? I do plan to gage some unfired rounds and see how they compare to some fired cases. If it's a sizing thing, I need to know. Sorry it's taken me so long to respond. I think my problem was I had two shell holders that were different thicknesses. I didn't realize that they weren't the same thickness. I was using them interchangeably and in turn it was causing the case to not get sized correctly. At least that's what I think happened. Once we were able to determine there was difference in thickness and I started using only one shell holder the problem went away. Thanks for the info. I used only my Dillon 550B to make this ammo, so I don't have that particular problem. Today, I did some work measuring case dimensions. I measured body diameter and runout at three locations along the length. I measured headspace. I checked dimensions for these four permutations: new unloaded brass (unsized, virgin brass), new brass that's FL sized and loaded (but unfired), once fired, reloaded brass, the recently fired brass (cleaned but not yet resized) In all cases the new and resized cases are smaller than the fired brass by several mils. In fact, the resized cases approximate the new, unfired brass dimensions and several times were actually smaller. This is true for body diameters and for headspace. The body diameter at the three locations grew by 4 to 5 mils after firing. Cases were sized to 1.460". Headspace after firing is 5 mils longer than before firing (which is a lot). There is a very slight "Coke bottle" effect on the case walls (~1 mil) of both the new and resized brass. I held a razor along the case wall and viewed it using a strong backlighting. The fired brass does not show this effect. All the brass is Winchester and is either brand new or once fired (previous range trip). It's all from the same batch. From this, I conclude my reloads are dimensionally acceptable. Did I miss something? I'm wondering if tilting the rifle upwards while operating the charging handle contributed to improper feeding and the resultant out of battery firing. <-- Was it just THAT simple? |
| I came to post the load may have been too LIGHT based on my lightweight bullet experiments. Ymmv. I've had a fee non catastrophic separations (why is there a 9mm or 9x23 brass on the floor? Why won't this next round chamber?) but never an oob or anything that bad. |
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Quoted:
I came to post the load may have been too LIGHT based on my lightweight bullet experiments. Ymmv. I've had a fee non catastrophic separations (why is there a 9mm or 9x23 brass on the floor? Why won't this next round chamber?) but never an oob or anything that bad. Yes, I think the load (light charge of slow powder and light bullet) may have been the root cause of this. Had the rifle been feeding and functioning properly, this would not have happened. Even if I had been single loading them into the chamber this would not have happened. |
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Quoted:
Thanks for the info. I used only my Dillon 550B to make this ammo, so I don't have that particular problem. Today, I did some work measuring case dimensions. I measured body diameter and runout at three locations along the length. I measured headspace. I checked dimensions for these four permutations: new unloaded brass (unsized, virgin brass), new brass that's FL sized and loaded (but unfired), once fired, reloaded brass, the recently fired brass (cleaned but not yet resized) In all cases the new and resized cases are smaller than the fired brass by several mils. In fact, the resized cases approximate the new, unfired brass dimensions and several times were actually smaller. This is true for body diameters and for headspace. The body diameter at the three locations grew by 4 to 5 mils after firing. Cases were sized to 1.460". Headspace after firing is 5 mils longer than before firing (which is a lot). There is a very slight "Coke bottle" effect on the case walls (~1 mil) of both the new and resized brass. I held a razor along the case wall and viewed it using a strong backlighting. The fired brass does not show this effect. All the brass is Winchester and is either brand new or once fired (previous range trip). It's all from the same batch. From this, I conclude my reloads are dimensionally acceptable. Did I miss something? I'm wondering if tilting the rifle upwards while operating the charging handle contributed to improper feeding and the resultant out of battery firing. <-- Was it just THAT simple? Quoted:
Quoted:
Quoted:
... bm3 said the same thing, above. In what way was it a sizing issue, or what aspect of your case sizing did you change as a result? I do plan to gage some unfired rounds and see how they compare to some fired cases. If it's a sizing thing, I need to know. Sorry it's taken me so long to respond. I think my problem was I had two shell holders that were different thicknesses. I didn't realize that they weren't the same thickness. I was using them interchangeably and in turn it was causing the case to not get sized correctly. At least that's what I think happened. Once we were able to determine there was difference in thickness and I started using only one shell holder the problem went away. Thanks for the info. I used only my Dillon 550B to make this ammo, so I don't have that particular problem. Today, I did some work measuring case dimensions. I measured body diameter and runout at three locations along the length. I measured headspace. I checked dimensions for these four permutations: new unloaded brass (unsized, virgin brass), new brass that's FL sized and loaded (but unfired), once fired, reloaded brass, the recently fired brass (cleaned but not yet resized) In all cases the new and resized cases are smaller than the fired brass by several mils. In fact, the resized cases approximate the new, unfired brass dimensions and several times were actually smaller. This is true for body diameters and for headspace. The body diameter at the three locations grew by 4 to 5 mils after firing. Cases were sized to 1.460". Headspace after firing is 5 mils longer than before firing (which is a lot). There is a very slight "Coke bottle" effect on the case walls (~1 mil) of both the new and resized brass. I held a razor along the case wall and viewed it using a strong backlighting. The fired brass does not show this effect. All the brass is Winchester and is either brand new or once fired (previous range trip). It's all from the same batch. From this, I conclude my reloads are dimensionally acceptable. Did I miss something? I'm wondering if tilting the rifle upwards while operating the charging handle contributed to improper feeding and the resultant out of battery firing. <-- Was it just THAT simple? You seem like a very thoughtful and thourogh guy. I don't think you missed anything. What my proplem boiled down to was I had an out of battery discharge. Same as you. I think mine was simply do to user error. The case was not sized correctly and it resulted in the rifle firing out of battery. The case was sized close enough that it fired but, I was also loading that particular round to near max published data with a 77 gn projectile. My pressures were way up there. It was a learning experience for sure. All I know is that it hasn't happened again and I changed my loading process to try to mitigate a reoccurrence. It's a process and we all eventually make mistakes. All we can do is try to learn from those mistakes. |
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