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Pictures of Corrosion. inside MEN94 cases.

This is a discussion on Pictures of Corrosion. inside MEN94 cases. within the Ammunition forums, part of the M14 M1A Forum category; Originally Posted by Mocos Quote:Originally Posted by m14nm I have always read that oil or any fluid in the firearms chamber can cause higher pressures. ...


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Old January 27th, 2012, 02:58 PM   #31
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Quote:Originally Posted by m14nm
I have always read that oil or any fluid in the firearms chamber can cause higher pressures. Not worth the risk.

Someone else may have a better answer or may be more knowledgeable on this.


+1 - When the cartridge is fired for just a fraction of a second the brass swells & "sticks" to the chamber.... when you have an oiled cartridge or chamber the brass does not "stick" so you have MUCH more pressure transferred to the bolt face, then on to the lugs & finally to the receiver....


I think there is a difference between being oily(leftover case lube and not totally cleaned off) and dripping with with oil either on the case or in the chamber. The oil is not compressable and essentially reduces the overall chamber volume and can elevate pressure by both not allowing the case to expand and/or provide the momentary sealing in the neck area when the round is fired. As far as the bore and chamber are concerned, it's general practice to oil it after cleaning to prevent rust so it is generally "oily/oiled" at the beginning of any shoot session??
Most reading I have done suggests that if one stores a firearm with an oily bore to prevent corrosion, one should swab it clean and dry before firing.

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Old January 27th, 2012, 05:05 PM   #32
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Oil in the bore will do this. Oil in the bore is an obstruction, not a lubricant.

It is unlikely that oil on a cartridge case will migrate to the bore, unless the cases are dripping wet.
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Originally Posted by LemmyCaution View Post
Most reading I have done suggests that if one stores a firearm with an oily bore to prevent corrosion, one should swab it clean and dry before firing.
don't ever recall ever doing that....but I always applied a thin coat of oil (currently mobil 1) handguns, rifles and shotguns..... factory brass comes with a slippery feel to it as opposed to squeeky clean...so whats on the brass? are your reloads squeeky to the touch?? my guess is that it is some kind of lubricant. As I said before, I think there is a difference between oilly and dripping with oil.

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Old January 27th, 2012, 05:36 PM   #33
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I know mine are squeaky clean. I tumble, lube, size, soak in soapy bath, rinse, tumble again, then re-anneal and quench,and force dry. Every time, no exceptions.

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Old January 27th, 2012, 05:57 PM   #34
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The internal corrosion is usually associated with failure to thoroughly wash or neutralize acids used in the manufacture of the powder. Not much to be done about it at this point.

(The excess calcium carbonate in some of the early powders used in the 5.56x45 M193 rounds were the flip side of the acid removal drama coin. Powder was stable, but the M16s got clogged up...)

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Old January 27th, 2012, 06:11 PM   #35
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The internal corrosion is usually associated with failure to thoroughly wash or neutralize acids used in the manufacture of the powder. Not much to be done about it at this point.

(The excess calcium carbonate in some of the early powders used in the 5.56x45 M193 rounds were the flip side of the acid removal drama coin. Powder was stable, but the M16s got clogged up...)
So you're saying the pink corrosion starts from the inside and eventually appears on the outside. That would suggest that the powder is contaminated ...all the more reason to toss em....or pull the bullets and maybe the powder to test for plinking rds using good brass.

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Old January 27th, 2012, 06:36 PM   #36
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JD-

Do you have evidence of a failure due to the phenomenon described above?

I don't doubt you, I'm just looking for a documented failure. The theory is totally plausible as is the notion that the lack of friction would contribute to wear on the affected parts.
This is a well known issue for any weapon but especially for semi-auto weapons whose bolts rely on recoil forces to operate. The technical term is Bolt Thrust. I know that it's fairly common for competition shooters to recommend waxing or oiling their cartridges so that they have reduced case stretch but it's a mistake. Older cartridges from the late 1800s and early 1900 would actually benefit from this but that was due to them using purely lead bullets and excessive fouling from the powder. Since weapons shifted to chamber pressures of 50,000 PSI or more, lubricated ammo has become a safety problem.

The first I heard of it was back in the late 1960s when my dad started teaching me how to reload. He was a WWII vet (Navy, south pacific, boatswain on landing boats). He learned about it in the military and he mentioned that some of the Camp Perry shooters that used the '03 Springfields talked about it. I later heard about it from M1 Garand shooters.

Recently I read about the issue in Earl Naramore's book "Principles and Practice of Loading Ammunition". Col. Naramore served at the Frankford Arsenal, Springfield Armory (while it was still the federal armory), and Erie Proving Grounds as an expert in small arms and ammunition. At the Erie Proving Grounds his posts were Chief Proof Officer, Chief of the Inspection Division, Operations Officer, and Executive Officer. After retirement he worked for several large commercial ammunition and reloading equipment companies.

In Col. Naramore's book he discusses the problem of oil causing increased bolt thrust. As an example, he discusses that fact that the British used a chamber pressure measurment process called the Whitworth or "oiled case" system. It was found that an oiled case will allow most of the chamber pressure to be felt at the bolt's face. They would put a crush washer between the bolt's face and the cartridge's base. The amount of compression was related to total chamber pressure. The process works because almost all of the chamber pressure forces are transferred to the bolt face.

In another book, "Rifle Accuracy Facts" by Harold R. Vaughn bolt thrust is also discussed. Mr. Vaughn points out that oiled cases increase bolt thrust by a great amount.

If you search the Internet for information about bolt thrust problems you will find a lot of examples of damage done to the rifle because people oil their cartridges. Here are two examples;

http://www.msgunowners.com/t9300-war...on-loaded-ammo
http://www.weatherbynation.com/spike...thrust/0/?wap2

This is an image of a Army Safety Bulletin from 2008


I did a post a while back explaining that the research that I've done indicates that the bolt face experiences about 8,000 PSI of pressure. That means that the lugs have to handle about 4,000 PSI each. If you oil your ammo then they experience much higher pressures. While they might not experience failure immediately this will cause stress fractures eventually. Nobody can predict how long it will take but it is definitely making the situation worse.

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Old January 27th, 2012, 06:41 PM   #37
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So you're saying the pink corrosion starts from the inside and eventually appears on the outside. That would suggest that the powder is contaminated ...all the more reason to toss em....or pull the bullets and maybe the powder to test for plinking rds using good brass.
Unfortunately, yes. But the powder is the culprit. So unless you intend on shooting the ammo you build using this powder immediately, the corrosion will start inside your "good" brass!

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Old January 27th, 2012, 06:48 PM   #38
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Oh, and the most important reason that I don't recommend oiling the ammo...

This is from the M1A owner's manual

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Old January 27th, 2012, 07:06 PM   #39
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The pictures show corrosion, caused by contact between the cartridge and the cardboard box it was packaged in. The pitting started on the outside and ate through the case causing the powder to become contaminated. Then the contaminated powder started to corrode the inside of the case.

I don't plan on using the powder to reload. I don't think there would be a problem if used right away, but, I have plenty of new powder for that.

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Old January 27th, 2012, 07:09 PM   #40
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This is a well known issue for any weapon but especially for semi-auto weapons whose bolts rely on recoil forces to operate. The technical term is Bolt Thrust. I know that it's fairly common for competition shooters to recommend waxing or oiling their cartridges so that they have reduced case stretch but it's a mistake. Older cartridges from the late 1800s and early 1900 would actually benefit from this but that was due to them using purely lead bullets and excessive fouling from the powder. Since weapons shifted to chamber pressures of 50,000 PSI or more, lubricated ammo has become a safety problem.

The first I heard of it was back in the late 1960s when my dad started teaching me how to reload. He was a WWII vet (Navy, south pacific, boatswain on landing boats). He learned about it in the military and he mentioned that some of the Camp Perry shooters that used the '03 Springfields talked about it. I later heard about it from M1 Garand shooters.

Recently I read about the issue in Earl Naramore's book "Principles and Practice of Loading Ammunition". Col. Naramore served at the Frankford Arsenal, Springfield Armory (while it was still the federal armory), and Erie Proving Grounds as an expert in small arms and ammunition. At the Erie Proving Grounds his posts were Chief Proof Officer, Chief of the Inspection Division, Operations Officer, and Executive Officer. After retirement he worked for several large commercial ammunition and reloading equipment companies.

In Col. Naramore's book he discusses the problem of oil causing increased bolt thrust. As an example, he discusses that fact that the British used a chamber pressure measurment process called the Whitworth or "oiled case" system. It was found that an oiled case will allow most of the chamber pressure to be felt at the bolt's face. They would put a crush washer between the bolt's face and the cartridge's base. The amount of compression was related to total chamber pressure. The process works because almost all of the chamber pressure forces are transferred to the bolt face.

In another book, "Rifle Accuracy Facts" by Harold R. Vaughn bolt thrust is also discussed. Mr. Vaughn points out that oiled cases increase bolt thrust by a great amount.

If you search the Internet for information about bolt thrust problems you will find a lot of examples of damage done to the rifle because people oil their cartridges. Here are two examples;

http://www.msgunowners.com/t9300-war...on-loaded-ammo
http://www.weatherbynation.com/spike...thrust/0/?wap2

This is an image of a Army Safety Bulletin from 2008


I did a post a while back explaining that the research that I've done indicates that the bolt face experiences about 8,000 PSI of pressure. That means that the lugs have to handle about 4,000 PSI each. If you oil your ammo then they experience much higher pressures. While they might not experience failure immediately this will cause stress fractures eventually. Nobody can predict how long it will take but it is definitely making the situation worse.

Thank you for posting this.

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Old January 27th, 2012, 07:14 PM   #41
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Unfortunately, yes. But the powder is the culprit. So unless you intend on shooting the ammo you build using this powder immediately, the corrosion will start inside your "good" brass!
ok....makes sense....good for starting fires then...or use as fertilizer? bullets need to be cleaned if reused...deprime the brass and sell it for scrap....

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Old January 27th, 2012, 07:23 PM   #42
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The pictures show corrosion, caused by contact between the cartridge and the cardboard box it was packaged in. The pitting started on the outside and ate through the case causing the powder to become contaminated. Then the contaminated powder started to corrode the inside of the case.

I don't plan on using the powder to reload. I don't think there would be a problem if used right away, but, I have plenty of new powder for that.
actually, sounds like two things going on....the green corrosion caused by the acidic paper and the pink corrosion from the "unclean" interior surface of the case reacting with the powder. From previous posts, green corrosion didn't cause perforation of the case walls but the pink exterior corrosion was "soft" and some time split when fired.

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Old January 27th, 2012, 08:32 PM   #43
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To show that the corrosion started on the outside of the cases, here's another photo showing the cases with a mirror behind them.
The center one shows the corrosion starting through to the inside, while the outer two, with a little heavier corrosion, has not.

[IMG][/IMG]

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Old January 28th, 2012, 03:32 AM   #44
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To show that the corrosion started on the outside of the cases, here's another photo showing the cases with a mirror behind them.
The center one shows the corrosion starting through to the inside, while the outer two, with a little heavier corrosion, has not.

[IMG][/IMG]
ok..assuming that both pink and green corrosion starts from the outside, have you any cases where the green corrosion has gone through the case wall.

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Old January 28th, 2012, 08:07 AM   #45
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ok..assuming that both pink and green corrosion starts from the outside, have you any cases where the green corrosion has gone through the case wall.
I think we have determined there is a problem with some of the DAG...how do we minimize the collateral damage?

so far from the comments the damage seems to be acid related...will applying a base solution of some type neutralize the acidic progress? ie salt water, baking soda solution...either by spraying or immersing? Are there any chemist types out there that can chip in here??

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