That would be nice. Irony is a form of humor I cannot do and barely understand. American's are poor at irony and I usually misunderstand ironic statements. American's are good at sarcasm, and I rant and rave loudly and use "poke them in the eyeball with a stick" sarcasm. Other forms of humor I may or may not comprehend the message.
How critical is it to remove lube from reloads?
- Thread starter berettaprofessor
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That would be nice. Irony is a form of humor I cannot do and barely understand. American's are poor at irony and I usually misunderstand ironic statements. American's are good at sarcasm, and I rant and rave loudly and use "poke them in the eyeball with a stick" sarcasm. Other forms of humor I may or may not comprehend the message.
Hummer70
Member
After I got set up with the stainless steel media I changed my entire reloading operation.
I fire the round, do what sizing is needed (neck/FL) and drop lubed cases in stainless media and Ivory dish soap and tumble them to remove the carbon and the lube.
After they are clean I will stress relieve the necks and or expand the necks to the dimensions I want to load to give a uniform bullet pull.
I fire the round, do what sizing is needed (neck/FL) and drop lubed cases in stainless media and Ivory dish soap and tumble them to remove the carbon and the lube.
After they are clean I will stress relieve the necks and or expand the necks to the dimensions I want to load to give a uniform bullet pull.
SLAMFIRE said:
MEHavey said:
SlamFire, my quote was a classic from the early days of nuclear weapons effect testing.SLAMFIRE said:
It means that real data does absolutely nothing to dispel erroneous belief held to the
point of religious zeal.
The True Believer simply ignores the data.(The Sun does go around the Earth, don'cha know)
postscript: Actually, I am in violent agreement with you.
Lubed/slick cases have no practical downside effect.
In fact the lube minimizes case stretch and extends life.
I appreciate the support, and the non subtle reply. I do have a bias, and that is I have been attacked so often on two Army lies (1. Greased bullets, and 2. slamfires are only caused by high primers and your worn out receiver bridge) that I expect an attack and tend to read ambiguous posts as an attack.
Absolute agree on this. For this one, the idea that grease and oil on cases dangerously create an over pressure condition is an argument based on authority, and that authority is the Army. This one goes way, way back, and it absolutely amazing given all the historical examples of weapons that used greased or oiled cartridges, that the American shooting community continues to believe an Army coverup dating back to 1920.
However what is even more amazing is that the Army continues to blame oil for problems it creates today. I am going to make the case that the current Army Ordnance Department exists in such an magnificent vacuum that they have NO clue what anyone has done, in fact, they are in such a vacuumatic state that they don’t even know what the hell they are doing...
I consider this recent study by the Army Ordnance Bureau as supporting my statement over their overall incompetence.
Analyzing Lubrication's Contribution to Cartridge Case Failure
www.dtic.mil/ndia/2011ballistics/11826.pdf
Since Hummer70 has popped in, maybe he can answer a few questions I have about the study, given that he worked at APG.
The main question, the primary question of this study, is “why are they testing ground equipment in an operational configuration at 160 °F?”. Hummer should remember that the maximum temperature for testing ground equipment in an operational configuration is 125 °F.
Another pertinent question, is what temperature range was the SAWS required to met. That is, was the SAWS supposed to be operated by a human at 160 °F? or is the 160 °F requirement simply the high storage temperature that it was supposed to survive in an non operational configuration?
Because in this presentation, the Army Ordnance Department is conducting operational testing at 160 °F and of course, the ammunition is over pressure at that temperature and causing malfunctions. I did check the specifications for the ammunition and all of the 5.56 cartridge specifications have a pressure limit at 125 °F. They don't have a pressure limit requirement at 160 °F. Which begs the question, why was the Army Ordnance Department firing SAWS at 160 °F with ammunition that was conditioned at 160 °F?
What I believe is that the Army Ordnance Department no longer knows that cooking ammunition deteriorates gunpowder and that pressures rise with hot ammunition. I also note, this presentation does not have a fundamental number: What is the design load of the bolt? This, along with the baseline procurement environments, should be all over this presentation. They are not. The Army should know the requirements it bought the weapons against, but it is clear, the Army does not know the loads that either Stoner or FN used in designing their locking mechanism. These numbers should be the basis of comparison in their presentation. It is as if, the Army expects the SAWS to have infinite load carrying capacity, which of course, it can't. All structures have a load limit, and the Army should know the limits for the items they own.
Aircraft design establishes two kinds of load conditions:
1. Limit Loads are the maximum loads expected in service. At the limit load that there should be no permanent deformation of the structure at limit load.
2. Ultimate loads are defined as the limit loads times a safety factor. Often the structure is required to withstand the ultimate load for at a couple of seconds without failure.
In the Army presentation, I don't see anything to indicate that the Army understands or knows either the limit loads or the ultimate loads, and therefore, is clueless as to why the SAWS structure is acting the way it is, under loads that exceed proof pressure loads. That is true for the SAWS and the cartridge case. But, they do blame oil for their problems....
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I hate to tell you guys but you are misinterpreting the data, you can't read just one slide of an oral brief and understand what was said.
Page 11 of the DTIC presentation says
I don't know why you choose to ignore the information on pages 12 and 13 that show that the static friction between the case and the chamber walls is reduced when you use lubrication and this results in a doubling of bolt face force (from 3000 pounds to over 6000 pounds). Page 18 shows a graph that specifically states that the case will fail when bolt face forces exceed 6000 pounds and the slide states that the failure was due to combined loads (forces). Finally, page 19, the summary, states that a combination of increased operating temperatures, lubricated chambers, and improper bolt design combined to cause the failures.
Also, this link http://proceedings.ndia.org/1210/11826.pdf will take you to a document that was written by the person who presented that DTIC slide (Mr. Mark Minisi) and he states very clearly that
Another document that summarizes the study says
Page 11 of the DTIC presentation says
Unfortunately you are taking this out of context. This slide indicates that lubrication didn't increase 'PRESSURE' - they aren't talking about force. It simply proves that chamber pressure is the same even with lubrication.
I don't know why you choose to ignore the information on pages 12 and 13 that show that the static friction between the case and the chamber walls is reduced when you use lubrication and this results in a doubling of bolt face force (from 3000 pounds to over 6000 pounds). Page 18 shows a graph that specifically states that the case will fail when bolt face forces exceed 6000 pounds and the slide states that the failure was due to combined loads (forces). Finally, page 19, the summary, states that a combination of increased operating temperatures, lubricated chambers, and improper bolt design combined to cause the failures.
Also, this link http://proceedings.ndia.org/1210/11826.pdf will take you to a document that was written by the person who presented that DTIC slide (Mr. Mark Minisi) and he states very clearly that
.
Another document that summarizes the study says
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MacGrumpy, the only effect a lubed case has is to reduce the work (force x distance)
done to stretch the thin brass section ahead to the case web back to the bolt face.
Stretching such thin brass under pressure eats up next-to-nil end-result bolt-face pressure.
Sorry guys, the physics/strength-of-materials just ain't there -- particularly as everybody
seems to love cleaning their brass to a mirror-finish anyway.
done to stretch the thin brass section ahead to the case web back to the bolt face.
Stretching such thin brass under pressure eats up next-to-nil end-result bolt-face pressure.
Sorry guys, the physics/strength-of-materials just ain't there -- particularly as everybody
seems to love cleaning their brass to a mirror-finish anyway.
Macgrumpy: Your post is an argument from authority, and your authority is clearly too incompetent to be taken seriously.
NDIA: Lube in your chamber is BAD
By Nick Leghorn on May 25, 2011
Normal M855 has a chamber pressure of 70,000 psia?! No, normal M855 does not have a chamber pressure of 70,000 psia. Normal M855 is not heated to 160 degrees, because at those temperatures it is above proof pressure .
This is the spec requirement for M855:
MILITARY SPECIFICATION 63989
Cartridge 5.56MM,
BALL, M855
3.7 Chamber pressure. The average chamber pressure of the sample cartridges, conditioned at 70 + 2°F shall not exceed 55,000 psi. Neither the chamber pressure of an individual sample test cartridge or the average chamber pressure plus three standard deviations of chamber pressure shall exceed 61,000.
Temperature extreme specified below shall be in accordance with
the following requirements.
a velocity of sample cartridges conditioned and fired at the at -65° + 2°F for not less than one hour and fired at that temperature
3.10.2 Chamber pressure. The average chamber pressure shall not vary from the average chamber pressure of the sample test cartridges conditioned to 70 + 2°F by more than 5,000 psi. Any decrease in chamber pressure is acceptable.
Conditioned at 125° + 2°F for not less than one hour and fired at that temperature.
The maximum allowable pressure of the M855 cartridge at 125 °F is 66,000 psia. If the lot exceeds that pressure than the lot is scrapped.
This means at 160 °F, the cartridge can have a pressure of 70,000 psia, 90,000 psia, 120,000 psia, 200,000 psia because the cartridge is not meant to be shot at 160 °F! Temperatures above 125 °F are outside the range of the cartridge, and therefore pressures are not controlled. If the Army tested M855 at temperatures above 125°F and found pressures in excess of 66,000 psia, they would find that the contractor had met contract requirements by building cartridges to the Army specification. Any pressure testing above 125 °F is outside of specifications and therefore the Army was testing out of specification.
There are no normal M855 pressures at 160 °F!. It is beyond specification requirements.
NDIA: Lube in your chamber is BAD
By Nick Leghorn on May 25, 2011
Normal M855 has a chamber pressure of 70,000 psia?! No, normal M855 does not have a chamber pressure of 70,000 psia. Normal M855 is not heated to 160 degrees, because at those temperatures it is above proof pressure .
This is the spec requirement for M855:
MILITARY SPECIFICATION 63989
Cartridge 5.56MM,
BALL, M855
3.7 Chamber pressure. The average chamber pressure of the sample cartridges, conditioned at 70 + 2°F shall not exceed 55,000 psi. Neither the chamber pressure of an individual sample test cartridge or the average chamber pressure plus three standard deviations of chamber pressure shall exceed 61,000.
Temperature extreme specified below shall be in accordance with
the following requirements.
a velocity of sample cartridges conditioned and fired at the at -65° + 2°F for not less than one hour and fired at that temperature
3.10.2 Chamber pressure. The average chamber pressure shall not vary from the average chamber pressure of the sample test cartridges conditioned to 70 + 2°F by more than 5,000 psi. Any decrease in chamber pressure is acceptable.
Conditioned at 125° + 2°F for not less than one hour and fired at that temperature.
The maximum allowable pressure of the M855 cartridge at 125 °F is 66,000 psia. If the lot exceeds that pressure than the lot is scrapped.
This means at 160 °F, the cartridge can have a pressure of 70,000 psia, 90,000 psia, 120,000 psia, 200,000 psia because the cartridge is not meant to be shot at 160 °F! Temperatures above 125 °F are outside the range of the cartridge, and therefore pressures are not controlled. If the Army tested M855 at temperatures above 125°F and found pressures in excess of 66,000 psia, they would find that the contractor had met contract requirements by building cartridges to the Army specification. Any pressure testing above 125 °F is outside of specifications and therefore the Army was testing out of specification.
There are no normal M855 pressures at 160 °F!. It is beyond specification requirements.
One other thing about case heads slamming against bolt faces and problems that occur.
Cases are like tube balloons; put pressure in them and they end up bent a little bit because their wall thickness is not uniform all the way around. So, the back end of a new case after its first firing is also curved a bit off its original position. It's out of square. If the bolt face is also out of square and pressure's at maximum, the case head ends up more out of square quite often.
Resizing then reloading that case that was fired in a standard 2-lug bolt action ends up with the case head still out of square; usually moreso. When it's fired again in a 2-lug action, its high point slams against the bolt face off center. That makes the barrel whip in an axis at right angles to that of the bolt lugs; typically sideways when the lugs are at 12 and 6 o'clock in the receiver. If the bolt face ain't square, it ends up more out of square. Full length sizing cases doesn't square up their heads. Creighton Audette ran a bunch of tests decades ago proving this and got about 1/3 MOA increase in horizontal spread with fired cases compared to new ones with rifles whose bolts were squared up. Over 1/2 MOA increase with rifles whose bolt faces were not squared up. If the high point of the case head was at 12 or 6 o'clock where the bolt lugs were, horizontal stringing was minimal and elevation stringing increased a little bit.
When military rifle teams shooting the 7.62 NATO round learned it was more accurate than the .30-06, they though reloading fired cases would be a cost savings thing to do. They tried it but because their M1 and M14NM bolt faces were not squared up with the chamber axis, shot stringing from 1 to 7 o'clock (their bolt lugs are in battery at 4 and 10 o'clock) happened with both commercial and arsenal match cases. So they quit reloading fired cases and shot only new ones which produced better accuracy.
Everyone won't notice this but those producing the best results in competition will. That's what the Brits did in the early 1970's after shooting arsenal 7.62 NATO ammo whose case heads were not all that square in 2-lug Mauser actions; they were not allowed to shoot commercial nor handloaded ammo because their rules stated everyone shoot the same lot of ammo. A gunsmith designed a 4-lug action (Swing) that minimized the horizontal shot stringing their 2-lug actions produced. To this day, 3- or 4-lug actions are preferred for Palma rifles used in international competition where everyone uses the same lot of ammo.
If you remove the case lube and have square bolt faces and case heads then limit head clearance for reloaded ammo to .001", bolts will close into battery very repeatable and minimal case "banana shaping" will happen and accuracy will be at its best.
Cases are like tube balloons; put pressure in them and they end up bent a little bit because their wall thickness is not uniform all the way around. So, the back end of a new case after its first firing is also curved a bit off its original position. It's out of square. If the bolt face is also out of square and pressure's at maximum, the case head ends up more out of square quite often.
Resizing then reloading that case that was fired in a standard 2-lug bolt action ends up with the case head still out of square; usually moreso. When it's fired again in a 2-lug action, its high point slams against the bolt face off center. That makes the barrel whip in an axis at right angles to that of the bolt lugs; typically sideways when the lugs are at 12 and 6 o'clock in the receiver. If the bolt face ain't square, it ends up more out of square. Full length sizing cases doesn't square up their heads. Creighton Audette ran a bunch of tests decades ago proving this and got about 1/3 MOA increase in horizontal spread with fired cases compared to new ones with rifles whose bolts were squared up. Over 1/2 MOA increase with rifles whose bolt faces were not squared up. If the high point of the case head was at 12 or 6 o'clock where the bolt lugs were, horizontal stringing was minimal and elevation stringing increased a little bit.
When military rifle teams shooting the 7.62 NATO round learned it was more accurate than the .30-06, they though reloading fired cases would be a cost savings thing to do. They tried it but because their M1 and M14NM bolt faces were not squared up with the chamber axis, shot stringing from 1 to 7 o'clock (their bolt lugs are in battery at 4 and 10 o'clock) happened with both commercial and arsenal match cases. So they quit reloading fired cases and shot only new ones which produced better accuracy.
Everyone won't notice this but those producing the best results in competition will. That's what the Brits did in the early 1970's after shooting arsenal 7.62 NATO ammo whose case heads were not all that square in 2-lug Mauser actions; they were not allowed to shoot commercial nor handloaded ammo because their rules stated everyone shoot the same lot of ammo. A gunsmith designed a 4-lug action (Swing) that minimized the horizontal shot stringing their 2-lug actions produced. To this day, 3- or 4-lug actions are preferred for Palma rifles used in international competition where everyone uses the same lot of ammo.
If you remove the case lube and have square bolt faces and case heads then limit head clearance for reloaded ammo to .001", bolts will close into battery very repeatable and minimal case "banana shaping" will happen and accuracy will be at its best.
Yes, I did it once, only off the cases and not the bullets, to see the difference. Improved 50 yard accuracy for a lot made in the early 1980's by about 1/50th MOA letting me shoot a 400-40X:
Otherwise, I'd probably shot a 400-39X as bull #4's X at 4 o'clock would have been a 10.. Considered it more luck than any accuracy issue so never did it again.
Rimfire match ammo has a peak pressure of almost 25,000 psi and its contact area on the bolt face is about .21" diameter putting only 865 pounds of force on the bolt face. Much less than centerfire ammo.
Otherwise, I'd probably shot a 400-39X as bull #4's X at 4 o'clock would have been a 10.. Considered it more luck than any accuracy issue so never did it again.
Rimfire match ammo has a peak pressure of almost 25,000 psi and its contact area on the bolt face is about .21" diameter putting only 865 pounds of force on the bolt face. Much less than centerfire ammo.
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OP
OP
berettaprofessor
Member
Necessity to remove case lube?....so I'd conclude from the thread (which went slightly off the rails) that one doesn't HAVE to; but one may or may not be risking bolt damage; and may have a very small increase in accuracy for 22LR that I probably won't notice, not being as good a shooter as Bart B.
Ask what you think is a simple question....get some great answers, some of them contradictory. Thanks Everyone.
Ask what you think is a simple question....get some great answers, some of them contradictory. Thanks Everyone.
Over time I've learned to not argue about things that I'm not qualified in, unfortunately MEHavey and Slamfire haven't seemed to learn that. It's blatantly obvious that none of us are qualified to argue about the actual science and engineering that went in to the DTIC report (unless you can prove that you are a ballistics expert that works in a test facility) but I'm very qualified to point out how these two posters have misinterpreted the DTIC report and how they lack knowledge about basic science and engineering principles. In that area of my abilities I can honestly say that neither of them know what they are talking about.
From MEHavey
I don't know how you feel qualified to make such a comment but it seems obvious that you've never analyzed the interaction between mechanical parts within a system, your comment sounds like somebody that had a little high school science and thinks that they are an engineer. You start your post by referring to how much work was done to the case when it stretches, using work as a way to define how a system functions is not the normal analitcal process. A work study is usually done when you want to analyze the conservation of energy. Mechanical systems are usually studied by analyzing the forces involved - as they did in the DTIC study. I think it's amusing that you either didn't read or simply don't understand the DTIC report. You claim that "Stretching such thin brass under pressure eats up next-to-nil end-result bolt-face pressure.". But Page 13 of the DTIC report shows quite clearly how wrong you are. That page shows a graph that shows the force on the bolt face was evaluated to be a max of approximately 3000 lbs with a dry case and a little more than 6000 lbs with a lubricated case, that's a little more than a 100% increase in bolt face force when you lubricate a case, that's hardly what I'd call a "next-to-nil end-result bolt-face pressure" change.
As for Slamfire's post
Seriously? Yes, my argument is an appeal to authority (the authority being the DTIC report/U.S. Army Research, Development and Engineering Command) and I feel far safer deferring to their studies, testing, and research than to believe some Internet expert that simply posts opinions with no personal expertise or test results to backup his comments, and who very often misinterprets or takes out of context information from valid resources. Additionally, I have a problem trusting the knowledge of an expert that has had several "slamfires" that could easily be explained by parts failures due to excessive forces from lubricated cartridges.
I really don't understand if you have a reading comprehension problem or if you just like to interpret things in a way that supports your world view, regardless of the reality of the situation.
You're correct, the ammunition is proofed according to the standards you quoted, but the point of the test was to recreate the field conditions rather than using optimum lab conditions. That's part of what the study revealed, that the real world conditions were far more severe than anyone expected. One of the articles that I linked to clearly states that the reason the cartridges were tested at 160 degrees is that the barrel of the M249 machine gun actually reaches those temperatures in the field (as those of us that have actually fired that weapon understand). The ambient temperatures in Afghanistan can reach 120 degrees, add to that the increase in temperatures when you've fired several hundred rounds during a firefight and it's pretty easy to see that the entire gun and the ammo will reach temperatures well above the proof temperature.
I think that your paranoid theories about government conspiracies makes you incapable of seeing the truth.
From MEHavey
I don't know how you feel qualified to make such a comment but it seems obvious that you've never analyzed the interaction between mechanical parts within a system, your comment sounds like somebody that had a little high school science and thinks that they are an engineer. You start your post by referring to how much work was done to the case when it stretches, using work as a way to define how a system functions is not the normal analitcal process. A work study is usually done when you want to analyze the conservation of energy. Mechanical systems are usually studied by analyzing the forces involved - as they did in the DTIC study. I think it's amusing that you either didn't read or simply don't understand the DTIC report. You claim that "Stretching such thin brass under pressure eats up next-to-nil end-result bolt-face pressure.". But Page 13 of the DTIC report shows quite clearly how wrong you are. That page shows a graph that shows the force on the bolt face was evaluated to be a max of approximately 3000 lbs with a dry case and a little more than 6000 lbs with a lubricated case, that's a little more than a 100% increase in bolt face force when you lubricate a case, that's hardly what I'd call a "next-to-nil end-result bolt-face pressure" change.
As for Slamfire's post
Seriously? Yes, my argument is an appeal to authority (the authority being the DTIC report/U.S. Army Research, Development and Engineering Command) and I feel far safer deferring to their studies, testing, and research than to believe some Internet expert that simply posts opinions with no personal expertise or test results to backup his comments, and who very often misinterprets or takes out of context information from valid resources. Additionally, I have a problem trusting the knowledge of an expert that has had several "slamfires" that could easily be explained by parts failures due to excessive forces from lubricated cartridges.
I really don't understand if you have a reading comprehension problem or if you just like to interpret things in a way that supports your world view, regardless of the reality of the situation.
You're correct, the ammunition is proofed according to the standards you quoted, but the point of the test was to recreate the field conditions rather than using optimum lab conditions. That's part of what the study revealed, that the real world conditions were far more severe than anyone expected. One of the articles that I linked to clearly states that the reason the cartridges were tested at 160 degrees is that the barrel of the M249 machine gun actually reaches those temperatures in the field (as those of us that have actually fired that weapon understand). The ambient temperatures in Afghanistan can reach 120 degrees, add to that the increase in temperatures when you've fired several hundred rounds during a firefight and it's pretty easy to see that the entire gun and the ammo will reach temperatures well above the proof temperature.
I think that your paranoid theories about government conspiracies makes you incapable of seeing the truth.
Greg Mercurio
Member
It's probably a good thing I wasn't drinking when I read the above. Perhaps with all your qualifications and experience you can explain how in a closed system, with no increase in powder charge, the application or presence of grease in the chamber or on the cartridge case can effect a near doubling of the INTERNAL force on the case head, which is then translated into EXTERNAL force applied to the face of the bolt?
I'm just a dumb, old, rocket engineer. Probably not nearly as smart as the rest of you, but I really want a reasoned answer.
Unfortunately MacGrumpy, I am a graduate engineer -- particularly in strength of materials
-- and even a basic course on cylindrical stretching of a very thin wall of soft material,
like brass, shows what little force is req'd.
And OBTW, Work is Force x Distance -- by it's very definition. It has nothing to do with
a "system," or conservation of energy, or anything else.
W=F*S
(You might want to look it up sometime)
It seems to me that all of us can agree that bolt pressure varies based on dry case vs. lubed case. I am not an engineer but, would not a gun manufacturer use the higher pressure of a lubed case as a working guide knowing that some of us do not clean off the lube?
I am wondering as a layman what pressures are used in designing the working strength of a firearm.
For me, I try to give all my finished rounds a quick wipe down before putting them into the storage case.
I am wondering as a layman what pressures are used in designing the working strength of a firearm.
For me, I try to give all my finished rounds a quick wipe down before putting them into the storage case.
OilyPablo
Member
Purely anecdotal. I ran 100 10mm lubed cases (homebrew lanolin/coconut, no wipe, lube noticeable by touch) loaded with 10gr of Longshot (0.5gr+ book) with 180gr FN FMJ vs. 100 unlubed cases exact same load. I saw or detected no difference.
As and aside I was mainly worried about the lube somehow interacting with powder. As noted above, undue worry. But still I have changed my lube recipe and will use a lot less.
As and aside I was mainly worried about the lube somehow interacting with powder. As noted above, undue worry. But still I have changed my lube recipe and will use a lot less.
Greg Mercurio
Member
solman: What do you base this on? This thread has gone 3 pages and not one person has substantiated what is to me, an urban legend. The engineers here have pretty thoroughly debunked the myth, but changing long held beliefs appears to be work for priests and exorcists, not engineers.
I AM an engineer, and the giggles this bolt thrust phenomenon provides me are priceless.
OilyPablo
Member
I thought we agreed lanolin and coconut oil in small doses don't chemically interfere with powder.
ADKWOODSMAN
Member
I compete in several shooting competitions each month.
For pistol calibers:45 Colt, 38 Sp.,38 Super, 45 Auto, .357 Mag. 45 Colt used in '73 clone.
tumble fired cases.
Resize in carbide die. First case is heavily covered in imperial sizing wax and wiped off.
Finish steps on a single stage press in batches of 50.
Never a problem with ammo in competition.
For pistol calibers:45 Colt, 38 Sp.,38 Super, 45 Auto, .357 Mag. 45 Colt used in '73 clone.
tumble fired cases.
Resize in carbide die. First case is heavily covered in imperial sizing wax and wiped off.
Finish steps on a single stage press in batches of 50.
Never a problem with ammo in competition.
My first slamfire was in a Garand, heavy NM Douglas barrel, using federal match primers. At the time, conventional wisdom, spread by shooters such as Bart B, were all telling the community that the only thing that caused slamfires were "high primers" and your worn out receiver bridge. My Garand slamfired out of battery during sitting rapid fire. I was not lubricating cases then.
The concept of sensitive primers did not exist at the time, and I was pretty sure all my primers were below the case, but I was not 100%.
My second slamfire was also in another NM Garand, shooting ammunition loaded with federal match primers. I had just received the rifle from the gunsmith, the receiver was cherry, new douglas match barrel, and the rifle slamfired out of battery when firing from the clip. This ammunition had been sized in a Bonanza match sizing die, and I had reamed all primer pockets to depth and seated all primer by hand, inspecting each and every round to ensure that primers were below the case head. At this junction I concluded that convention wisdom that only high primers and your worn out receiver bridge was bunk.
Since then I have been using the least sensitive primers in my rifles, because, baring mechanical issues, the primary cause of slamfires is primer sensivity. The Garand mechanism has a design defect in that it allows incidental contact between the firing pin and primer, before lockup. This defect was never talked about and deliberately suppressed.
What I am interested to you to explore this idea that
How does high pressure cause slamfires? What parts have to break to cause an out of battery slamfire? Before you start stating that hammers or firing break due to high pressures, I am still using the trigger group from the second slamfire incident, no problems, the bolt was OK and the firing pin not broken. I am still using that bolt when the rifle was rebuilt. The first one, I don't think I lost any bolt parts, though extractors often get blown out. I still have the bolt. The trigger was fine and used again as is. I might still have that trigger group because the trigger had an excellent pull, but I did sell that action in a new stock. I remember replacing the old stock, the elevation knob, the action on the first rifle was usable after the gunsmith worked on it. The second one the receiver heel was knocked off.
So, how does high pressure cause a slamfire? What part failures caused by high pressure cause a slamfire?
Or is your major malfunction a case of "evil things happen to evil people"? Someone you know has a flat tire and therefore they are a liar, untrustworthy, because you, the righteous one, never had an accident? Are you one of those Puritans that believe that the hand of God is lifted from the unrighteous and therefore you can identify the damned by the misfortune that comes their way?
The point about the competence of the Army Ordnance Corp. A sack of potatoes has more intelligence than the average Army Engineer. The difference between potatoes and an Army Engineer is that no matter how long you cook them, the Engineer will always end up half baked.
Did anyone notice this recent Army Scandal?
Missing batteries among issues that caused Army's runaway blimp
http://www.latimes.com/nation/la-na-runaway-missile-defense-blimp-20160214-story.html
The Army report is classified, but pieces leaked out. Someone forgot to put batteries in the auto deflation device. This blimp terrorized the Pennsylvania country, causing F-16 ' to be scrambled as the thing took out the power gird and scared live stock. Eventually Sheriff Deputies shot it down with shotguns.
Seems the $2.00 Billion Jlens blimp had a system failure of the pitot tubes. The altitude control system lost its elevation and than the blimp tilted instead flying horizontal. Winds broke it loose from its moorings. The auto deflation device should have engaged and deflated the balloon but one of those brilliant Army Engineers forgot to put the batteries in. Oops! If you notice, the Army is not really talking about this. I guess you did not learn in whatever service you served that firearms have thermal limits. Good thing you did not encounter a human wave attack, such as some of my buddies did in Korea. They told me about the importance of keeping both your ammunition and your machine gun cool. Cooking ammunition to 160 F and then firing it in a 160 F machine gun is going to cause malfunctions. My bud's told me about fire control and burst control. You hold down the trigger and keep firing, and your gun will jam. If not burst in fire.
Took this guy 300 rounds to cause the handguards on his AK47 to burst in flames
https://www.youtube.com/watch?v=eNAohtjG14c
And that is what the Army re discovered. Heat is bad. Weapons and ammunition can over heat. Heat does not magically transport itself into the ether along with that bolt thrust caused by overpressure cartridges. It is apparent, they forgot these things. Just as it is apparent you don't recognize that structures have thermal and structural limits. Didn't they teach about the limits of squad weapons, and the differences between heavy weapons and light weapons, and issues of sustained fire?
Since you are so knowledgeable about these things, just what are temperature ranges in the SAWS Prime Item Development Spec. Maybe you know the number, I have not found either the spec, or a number reference. That should be in the report. I believe the Army lost the spec. They don't have it anymore. What I was told they bought the SAWS as a fully developed weapon, that is, COTS. Whatever procurement documents date back to the 1970's and I will bet that every body from then retired, and every paper file was dumped when the Army went to the paperless office. (Ha!) I am of the opinion the Army no longer knows what technical requirements the weapon was purchased against and only the contractor knows. I remember the 1970's and we were not going to be attacking our Best Foreign Friend (BFF) Saddam Hussein. He was kicking Iranian butt and we were cheering from the side lines. At the time, we were worried about the Russian juggernaut, nuclear winter, and the Russian winter. Contract requirements are very important things, if the Contractor is building SAWS to the Contract requirements, that is, the technical performance requirements in the Prime Item Development Spec (B1) from the 1970's, then any changes coming out of this 160 F test, are added scope. The Contractor will press the Government for hundred's of millions of dollars to redesign the SAWS to the new requirements. Do you have signature authority to commit the American Nation for an expenditure of hundred's of millions of dollars because you want a SAWS to operate at 160 F with 160 F ammunition? Do you know anyone who has that authority? Or are you just some person who wants something, but really does not understand what they are asking for? That is, so incompetent, that you don't realize that you are incompetent? You questioned Mehavey's qualifications?!! Just what are your technical qualifications?
Incidentally, yes, temperatures in Iraq reached 121 once, I have not studied Afghanistan, but certainly 120 is achievable. I have been in the Mohave Desert and that was very darn hot. So, do you expect to fight in 160 F weather? What are the human limits of survival at 160 F? Maybe I should say, you know what to call a human in 160 F heat? : a dead person!! . How long could you survive in MOP IV, in 160 F weather? Ever thought about it?
It is my opinion that the Army showed its incompetence by testing weapons out side of the range of human survivability. They also were clueless about their own temperature requirements, just as you are. Ever heard of Mil Std 810? No, I did not think so. Just what are the operational environments for ground equipment and the storage conditions?. I don't think the Army knows either. They were in violation of their own standards. They exceeded the temperatures they contracted for the weapon and its ammunition.
So, what remedial efforts did the Army take for the SAWS? What hardware changes did they make for the weapon and ammunition to fire full sustained automatic fire at 160 F with 160 F ammunition? If the weapon is defective, what did they do to fix it?
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Greg Mercurio- I thought that the bolt pressure variation was a given and wether or not it was a problem was in question.
I must have been mistaken.
It seems to me that it wouldn't be all that difficult to test pressure on the bolt with a clean dry round vs. a lubed round that has not been cleaned off.
Anyone know if this has been done?
I must have been mistaken.
It seems to me that it wouldn't be all that difficult to test pressure on the bolt with a clean dry round vs. a lubed round that has not been cleaned off.
Anyone know if this has been done?
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Varmit Al did a finite element analysis: This is a computer model and very interesting. Notice, if you want the case to carry load, the case head is stressed, which is exact the worst place for the case to carry load.
http://www.varmintal.com/a243z.htm
British proof test is conducted with lubricated cartridges . This test is technically correct, unless the cartridge is lubricated the locking mechanism is not fully loaded, due to parasitic friction between the case body and the chamber. Therefore any proof tests with dry cartridges and dry chambers is technically unjustifiable as the locking mechanism is not as uniformly loaded as the chamber. This is recognized in NATO EPVAT testing. https://en.wikipedia.org/wiki/NATO_EPVAT_testing NATO EPVAT testing specifically calls out the testing of firearms with an oiled proof load as the final test.
When the proof house stamps its proof stamp on a weapon, its reputation is at stake. A proof house has to show relevance and provide assurance of quality or its existence will be questioned. America does not have a formal proof system, American manufacturer's have their own methods, geared towards lowest cost. I am unaware of American manufacturer's proofing with lubricated cases, but, they could. Since the liability is their own, they do what they want to do.
Test results from the British proof house did show that the bolt thrust with dry cases in dry chambers was about 25% less than with lubricated cases. However, that thrust was being carried by the case sidewalls and that is why cases stretch. Anyone who thinks that this thin brass tube is there to take load off a bolt with a shear path through 1/2" of steel, needs to have their head examined.
Something that the Army study did verify, and this was critically important, was that oil on the outside of the case did not raise combustion pressures. This chart shows that.
In fact, what is very hard to see, is that grease and oil on the cartridge actually decrease chamber pressures. Oil and grease get squeezed ahead of the bullet, lubricating the bullet through the chamber throat. This reduces friction and thus, pressures inside the barrel and chamber are less. This is 100% contradictory to the Army claim in 1920, that grease and oil "pinched" the case neck and raised pressures. Grease and oil move, they don't pinch anything. Something else about lubricated cases that I am studying, is the effect on fouling. It is well known that greased bullets eliminate jacket fouling, at least it was prior to WW2. I have been shooting NRA Bullseye Pistol and lubricating my cases. Recently I shot a 2700 and I used almost two ounces of motor oil lubing my cases. What I am noticing is the absolute absence of bullet leading. It is most remarkable when I push a patch through the barrel of my M1911 and look through the tube, just how bright and clean the thing is, even though I have fired 180 rounds of 200 gr LSWC through it. There is zero leading in the throat, in the tube. I am going to continue to monitor this and see if it is due to the oil or not.
The Army did conduct bolt loading tests, but I forget just how they did it. With modern transducers' they could have fired a case in a test barrel and measured the case thrust on the transducer with or without oil or grease. It is unfortunate but the Army does not have any weapon designers on staff anymore. The Army technical staff is basically Technical Contract Specialists, they don't design anything. They don't have the software packages used in the presentation, their support contractors did that work. The Army has lost its in-house organic technical capability and it shows in the report. They don't know what loads are used in sizing the bolt lugs, or the barrel diameters. They only know differences in loads. If the load went up, that is bad. If it goes down, that is good.
They should have explained, why this worked, and theirs does not:
And why this works, and theirs does not
This is a Colt concept cartridge with plastic sidewalls. If the case is to carry load, and carry it through the sidewalls, than this concept is unsound.
Colt proposed this case design too, and if cases are supposed to carry load, this would not work either.
I believe in the technical competency of the Colt Engineers over the Army Engineers any day. Anyone seen a blimp recently?
Greg Mercurio
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Slamfire: Outstanding.
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