Ran into some problems load testing today. Case damage I have never seen before
- Thread starter Roddy
- Start date
I scanned throught but didn't see if these questions were asked/answered. Do all the primers show primer flow as the single example shown? If they do then you did something consistently wrong or something was consistently out of spec to create the high pressure. Some brass could take it others could not. If they are not consistent then there was variable failure in the process.
You also mention mixed brass and you are shooting 308. Have you mixed in 7.62 military brass in with the commercial brass and loaded the same charges? As the military brass is thicker and therefore the case capacity is less the recommendation is to lower the powder charge for military cases
Edit please disregard I just noticed that all the cases are federal
You also mention mixed brass and you are shooting 308. Have you mixed in 7.62 military brass in with the commercial brass and loaded the same charges? As the military brass is thicker and therefore the case capacity is less the recommendation is to lower the powder charge for military cases
Edit please disregard I just noticed that all the cases are federal
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I only use a triple beam and trickle the last bit in. All other loads were good and this one clocked at 2599 fps. I don't have any other rounds made up. I may have a bolt shaped hole in my head if it wasn't a big long action German rifle. I have read several reloading manuals and handbooks. I like to think I am very careful.
The gunsmith said he had seen it once before but didn't recall the details. He thought perhaps poor annealing may habe cobtributed. The rifle is fine.
Andy I don't know as I don't have any loaded rounds right now. I will post pictures of the case after I cut it in half buy that's about all the information I have.
Again every item had been used to make hundreds of rounds before. No new components were introduced and no other rounds showed any signs of high pressure. At 43.5 grains the case is full to the shoulder. I don't think I have the case volume to cause a massive overpressure from too much powder.
Here are 17 of the other 20 rounds I fired after that, all loaded as hot or hotter, all sub MOA. Six were from the same batch.
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That case looks to me like a classic example of very soft brass.A friend of mine gave me some brass he had been saving out of his rifle for me but neglected to tell me he had them stored in a metal coffee can on his garage woodstove to keep them dry or ??,forget the exact reason as this was 25+ years ago.They were basically soft from top to bottom but I didn't know it.I loaded them up for my 308 at the time,Rem 700,and the very first round I fired made one helluva blast.The 700 action combined with a mild start load saved the day.The brass was literally extruded into the bolt face and I had a heck of a time getting that case out.Luckily for me the rifle was OK and I got away with only having to change my underwear.Just my own opinion on the matter,others may vary.
You said this was the first round of the day. by some chance did you clean the bore and OIL it? I've seen this once before, it happened in a rifle that was oiled for storage and not patched before shooting it! the pressure spike was near catastofic.
I agree with eagleye. That issue was not caused by a bullet only .003 over bore diameter. I doubt very much it would even have been noticed either with velocity or recoil. There is a lot of misunderstanding of bullet diameter and its effect on pressure. Bullet weight on the other hand has a great effect.
I have had a similar thing happen to some of my reloads. Thankfully not often. In almost every occurrence it was a squib load. It was also my fault because I was in a rush and didn't check the case each time to make sure the powder level was consistent. On one occasion it was caused by powder left in the measure. I had dumped off the powder in the silo but hadn't been careful to dump the powder in the measure below. STUPID. I had been loading for 357 maxi rifle loads in my Martini and was using a very fast powder. I went to 7-08 and switched to H414SL10. I turned the volume screw down to a known point and when I threw the first charge it was very close and topped it up with a trickler. You would thing I would have been smart enough to look at the powder in the pan on my scale. I wasn't. That is what being in a hurry and just to confident does to you. I poured that powder into the first case and proceeded with the rest of the cases, weighing every tenth throw as usual all was well.
As luck would have it, the first case loaded was fired last. My case looked just like yours other than there was a bit of the second rim missing. It had gone out the vent hole on the side of the receiver thankfully. I have to wear glasses so I was protected but if you don't wear safety or other glasses while shooting, your eyes are in peril. You may have come very close to some serious eye injury.
Often squib or mixed powder loads are blamed on being something else. You're pics are typical of grossly mismatched powders or a squib load.
This is just IMHO of course.
Whatever, just be more careful in the future. Don't trust the volume drum on your powder measure to drop all of its powder. As far as a digital powder meter and scale combo go there is an even better chance of mixing powders if you don't scrutinize the first loads closely.
I have had a similar thing happen to some of my reloads. Thankfully not often. In almost every occurrence it was a squib load. It was also my fault because I was in a rush and didn't check the case each time to make sure the powder level was consistent. On one occasion it was caused by powder left in the measure. I had dumped off the powder in the silo but hadn't been careful to dump the powder in the measure below. STUPID. I had been loading for 357 maxi rifle loads in my Martini and was using a very fast powder. I went to 7-08 and switched to H414SL10. I turned the volume screw down to a known point and when I threw the first charge it was very close and topped it up with a trickler. You would thing I would have been smart enough to look at the powder in the pan on my scale. I wasn't. That is what being in a hurry and just to confident does to you. I poured that powder into the first case and proceeded with the rest of the cases, weighing every tenth throw as usual all was well.
As luck would have it, the first case loaded was fired last. My case looked just like yours other than there was a bit of the second rim missing. It had gone out the vent hole on the side of the receiver thankfully. I have to wear glasses so I was protected but if you don't wear safety or other glasses while shooting, your eyes are in peril. You may have come very close to some serious eye injury.
Often squib or mixed powder loads are blamed on being something else. You're pics are typical of grossly mismatched powders or a squib load.
This is just IMHO of course.
Whatever, just be more careful in the future. Don't trust the volume drum on your powder measure to drop all of its powder. As far as a digital powder meter and scale combo go there is an even better chance of mixing powders if you don't scrutinize the first loads closely.
Below is an illustration of over pressure and brass flow.
If I understand your posting correctly only the first cartridge fired showed these signs.
The only thing I can think of that would cause this is grease or oil in the chamber and bore. This would keep the case from expanding to fit the chamber walls and reduce the case capacity increasing pressure. Then this oil or grease in the chamber is forced forward adding to any oil or grease in the bore that the bullet has to push out of the way and increasing chamber pressure.
Always dry your chamber or bore before shooting, any oil or grease in the chamber increases bolt thrust, and any oil or grease ahead of the bullet will greatly increase chamber pressure.
Below from the Sierra reloading manual
From the US Army
Springfield Armory
Lyman reloading manual
And my favorite the 1929 British Textbook of Small Arms (bolt action Enfield rifle)
The British used the "base crusher" system where the copper crusher was located at the base of the case. The copper crusher had a hole in the center for the firing pin to pass through and the case had to be oiled to measure the correct chamber pressure. And above states the case would only register half the pressure when the case was dry as it should be in normal operation. Meaning a oiled chamber doubles the bolt thrust to the locking lugs and will over time increase your headspace. The Enfield rifle fired two oiled proof pressure rounds and if the headspace increased over .003 the rifle failed proofing.
If I understand your posting correctly only the first cartridge fired showed these signs.
The only thing I can think of that would cause this is grease or oil in the chamber and bore. This would keep the case from expanding to fit the chamber walls and reduce the case capacity increasing pressure. Then this oil or grease in the chamber is forced forward adding to any oil or grease in the bore that the bullet has to push out of the way and increasing chamber pressure.
Always dry your chamber or bore before shooting, any oil or grease in the chamber increases bolt thrust, and any oil or grease ahead of the bullet will greatly increase chamber pressure.
Below from the Sierra reloading manual
From the US Army
Springfield Armory
Lyman reloading manual
And my favorite the 1929 British Textbook of Small Arms (bolt action Enfield rifle)
The British used the "base crusher" system where the copper crusher was located at the base of the case. The copper crusher had a hole in the center for the firing pin to pass through and the case had to be oiled to measure the correct chamber pressure. And above states the case would only register half the pressure when the case was dry as it should be in normal operation. Meaning a oiled chamber doubles the bolt thrust to the locking lugs and will over time increase your headspace. The Enfield rifle fired two oiled proof pressure rounds and if the headspace increased over .003 the rifle failed proofing.
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Well if it was a squib would it not have left the barrel and hit point if aim?
It could possibly be oil. I don't usually dry the chamber very well but I did not clean it after the last time out as I don't want to change anything while developing a load. But maybe something migrated in there.
I polish my brass after sizing so it wouldn't be case lube.
I am having trouble posting the picture of it cut in half but the case expanded right where the flash hole is. A bit lower than in the diagram above, right at the thickest most solid part of the case.
I am leaning towards a one off bullet problem or possibly a brass problem. Some of the head stamps look to be slightly different and don't appear to have the blue primer sealant I am used to seeing.
For people saying I shouldn't use other people's load data the loads I tried were lighter than my own, so what is the risk there?
Thank you everyone very much for your input. It is much appreciated. I feel I have looked into everything and never really found a smoking gun (except for the SSG 3000 right after the case got stuck).
The rifle is no worse for wear, I have settled on a load, and I am going to work on my loading and shooting and be more meticulous inspecting my brass.
It could possibly be oil. I don't usually dry the chamber very well but I did not clean it after the last time out as I don't want to change anything while developing a load. But maybe something migrated in there.
I polish my brass after sizing so it wouldn't be case lube.
I am having trouble posting the picture of it cut in half but the case expanded right where the flash hole is. A bit lower than in the diagram above, right at the thickest most solid part of the case.
I am leaning towards a one off bullet problem or possibly a brass problem. Some of the head stamps look to be slightly different and don't appear to have the blue primer sealant I am used to seeing.
For people saying I shouldn't use other people's load data the loads I tried were lighter than my own, so what is the risk there?
Thank you everyone very much for your input. It is much appreciated. I feel I have looked into everything and never really found a smoking gun (except for the SSG 3000 right after the case got stuck).
The rifle is no worse for wear, I have settled on a load, and I am going to work on my loading and shooting and be more meticulous inspecting my brass.
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PitBull1973
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Good luck hope everything works out for you. Cheers
bclinehand
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looking at the picture of your fired cases 2 front and 9 look like they have primer cratering from over pressure. ....
A place like this could do it:
http://www.qualimet.ca/metallurgical-testing.htm
The cost might be prohibitive though.
I don't see it but I am new at this. Also I am not the best st taking pictures so it could be the lighting. Here are some more pictures with those two cases on the left and two random cases on the right:
And here is the case problem case cut open. There is a bit if a burr on the inside edge and the picture isn't the greatest so I don't think it will tell anyone anything but maybe:
Again thanks for all the help and advice.
Oh and I just checked on a round because someone asked earlier. Outside neck diameter 0.336-0.337 after seating. The same as before seating pretty much.
One more thing to add. Probably doesn't mean anything but I thought it might help.
These cases have different headstamps:
The writing on the top one is smaller and there is a weird mark just to the side of WIN on the top one.
About 10% of the cases I bought were like this. I am assuming they are very old and I have separated them.
These cases have different headstamps:
The writing on the top one is smaller and there is a weird mark just to the side of WIN on the top one.
About 10% of the cases I bought were like this. I am assuming they are very old and I have separated them.
I have experienced what you just have a couple of times..........the cause is an oversize flash hole. I was doing load testing for a 243 and everything was ticking along nicely when wham, I got a face full of blow back. Opened the bolt and had the primer exit before the case and the case looked exactly like yours. This was the third in a rack of 4 and only midway to my max loads. I looked long and hard at the previously fired cases and deemed that I was no where near hot yet, so I fired the fourth round without incident. Then proceeded on through the remaining 2 hotter loads without incident.
When back at my loading bench I inspected the failed case very closely and noticed the primer flash hole looked very oversize. I then checked a few other cases I have laying around that had blown primers for one reason or another and the flash holes appeared normal.......HHHMMMMMMM.
This was brand new unfired brass I was working with so no other fools folly had come into play. I then decided to check the rest of the 3 bags of new brass and low and behold I found another one with a flash hole appearing to be about 50% too large. I promptly loaded up the same load as previous and with 4 cases including the oversize flash hole one. Guess what..........exactly the same result......3 good ones and 1 blown case. I did wear a grinder face mask this time..........
PS.......in that photo of the sectioned case that blew, the primer flash hole looks significantly oversize to me.
When back at my loading bench I inspected the failed case very closely and noticed the primer flash hole looked very oversize. I then checked a few other cases I have laying around that had blown primers for one reason or another and the flash holes appeared normal.......HHHMMMMMMM.
This was brand new unfired brass I was working with so no other fools folly had come into play. I then decided to check the rest of the 3 bags of new brass and low and behold I found another one with a flash hole appearing to be about 50% too large. I promptly loaded up the same load as previous and with 4 cases including the oversize flash hole one. Guess what..........exactly the same result......3 good ones and 1 blown case. I did wear a grinder face mask this time..........
PS.......in that photo of the sectioned case that blew, the primer flash hole looks significantly oversize to me.
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This - already an overpressure sign - the high pressure caused the brass to flow into the extractor relief in the bolt face.
I'd take ALL of that brass in for scrap, and start fresh - either from factory ammo or new brass.
I'd be inclined to agree with this post, I've had so much grief with Fed and Horn brass being too soft and weights varying as much as 15 grains in the same batch, that I refuse to use them any more. I use W-W, Lapua (in cases that they make) and R-P..........Lap and W-W will take much hotter loads with out brass flow, R-P although somewhat softer is still quite consistent and still much harder than Fed or Horn.
