Oiling cartridge cases can be dangerous and other mishaps

[Doug Bowser]

I had a guy bring a Savage Model 99 in .243 Win to my shop. He had a case head separation and it blew the buttstock off the rifle. He had some problems with extracting empty brass and he was oiling his ctg cases. It increased headspace due to increased bolt thrust. The field gauge would rattle in the chamber. He wanted me to re-barrel it and I refused. You could see the indentation in the locking surfaces in the rear of the receiver.

Model 94 in .32 Win Special. This rifle had been given a diet of maximum loads for about 16 years. I believe the headspace was excessive. He overloaded a round and the rifle blew up. The extractor hit him in the forehead and his face looked like a load of buckshot hit him. The bolt was jammed 1/4" out of battery and he rear of the ctg case was gone. It bulged both sidewalls of the receiver and blew the loading gate off the rifle. He also wanted me to re-barrel the rifle and I refused.

Model 1893 Spanish 7x57 rifle. brought in because the owner wanted to know what caliber it was. I told him it was a 7x57 Mauser. He said the guy where he bought it said it was a .308 Winchester. I tried to check the headspace and the gauge would not work. There was a ctg case in the chamber. I used a headless case remover and discovered a headless .308 case in the rifle. He said he fired the .308 in it. He had to beat the bolt closed to chamber the round. He also said it kicked like hell. I checked the headspace and it was in tolerance. I told him to use 7x57 ammo next time. I also checked the locking lug recesses for an signs of setback and there was no sign of it. So much for Spanish rifles being soft.

I wanted to relate these stories because I think we should all be forewarned about the dangers of reloading and doing things with rifles that are not recommended.

Doug Bowser

 

[mete]

It's hard to deal with stupid people ! And they're the ones who raise costs in the liability lawsuits.

 

[mrawesome22]

No danger whatsoever in reloading.

Dumb people do dumb things.

sudo apt-get update

 

[FiveInADime]

No danger whatsoever in reloading.

Dumb people do dumb things.

sudo apt-get update

Seriously, only one of those stories related to reloading. The guy made a mistake in a weak rifle. Not really indicative of the danger most people will face in reloading.

Sent From My Galaxy S 4g Using Tapatalk

 

[tobnpr]

"oiling" his cases?
First...why? Second...what an idiot...

I'm so paranoid about getting every bit of case lube off the cases I've about worn out my wrist from cleaning them off after a reloading session.

 

[RC20]

The second one is re-loading related (enabled and driven by gross stupidity)

I am not sure you can equate one to the other, nor would I expect the idiot to listen (ergo replace the barrel and we are good to go)

I do like the oiling the cartridges one. Hmmm.. Guess the end of comment one applies there as well.

All good things to write about.

 

[FrankenMauser]

"oiling" his cases?
First...why? Second...what an idiot...

It's an old-school method for easing extraction in rifles that might have sticky chambers, or in rifles that see high chamber temperatures.
Oiling cartridges does, arguably, have its place. But... a Savage 99, is not that place, especially with a high pressure cartridge like .243 Win.

 

[tobnpr]

Never heard of that.

"Sticky chamber" or not, I can't see any application where that could be safe. The case must be able to expand and grip the chamber walls when fired.

 

[Slamfire]

I had a guy bring a Savage Model 99 in .243 Win to my shop. He had a case head separation and it blew the buttstock off the rifle. He had some problems with extracting empty brass and he was oiling his ctg cases. It increased headspace due to increased bolt thrust. The field gauge would rattle in the chamber. He wanted me to re-barrel it and I refused. You could see the indentation in the locking surfaces in the rear of the receiver.

I would be curious to know what loads the 243 shooter used. I have no confidence that his loads were anything but over pressure reloads. Whatever bolt thrust reduction dry cases provide, it is inconsequential. Cases are always operating in yield: they are stretching, cartridge cases are not structural members, they must be supported or they will rupture.

This idea that lubricated cases are dangerous start with Hatcher and the 1921 tin can ammunition coverup. It was further extended by P.O Ackley and his claims that case taper reduces bolt thrust, therefore his overpressure Ackley Improved cases were “safe”

These claims are and were 100% bogus. High pressures are a result of too much powder in the case. A sloppy reloader adding a couple of grains over max can raise pressures well over 80 Kpsia, well over 100 Kpsia, to the point that the brass flows as a liquid.


There were many fielded machine gun designs that used lubricated cases, given normal cartridge pressures they did not, and will not, increase headspace.


Section 11 Cleaning for the Model 42B Ljungman is quite explicit, lube your cartridges, when the chamber gets dirty, clean it and lubricate the chamber and the cartridges.


http://pdf.textfiles.com/manuals/FIREARMS/ljungmann_ag_42b.pdf

http://forums.gunboards.com/showthread.php?70299-The-AG-42-For-Slowfire-Prone-And-Offhand

http://www.surplusrifleforum.com/viewtopic.php?f=47&t=11436


The Schwarzlose machine gun was another, look at the wonderful pictures at this Swedish site, and of course, you can see the oiler.

http://www.gotavapen.se/gota/artiklar/utv_ksp58/ksp14/schwarzlose.htm

The Japanese Nambu used an oiler:

The Italian Breda 30 used an oiler

Oilers were designed out of mechanisms after WW2. The Germans captured a Russian machine gun that had a fluted chamber, copied it in their assault rifles, and that ended the need for oilers.

I don’t know why FN did not use chamber flutes, but on their 5.7 cartridges, they are using Teflon. I have read on other forums that injuries have occurred when shooters reloaded their cartridges and rubbed off the Teflon. It is likely the cartridges ruptured on extraction, but I really don’t know what happened.

http://en.wikipedia.org/wiki/FN_5.7×28mm

FN's 5.7×28mm cartridge cases are covered with a special polymer coating for easier extraction with the PS90 carbine due to the high chamber pressures and lack of case tapering.[32] In addition, this coating ensures proper feeding and function in the magazines.[32]


As for those who claim case friction is necessary or the bolt will be overloaded, what do you do with these two piece polymer cases? Do notice the brass case head that provides the case seal. How much load can that polymer/brass joint actually carry?

It turns out not much. The problem with that ammunition was that the front of the case stayed in the chamber messing up function with the next round.

So this is polymer case 2011, Oh there is a metal case head in there someplace, but the sidewalls are plastic.

There are two factors which lubricated cases could cause problems. The first are bottlenecked cases with too much headspace. A case with excessive headspace is going to peen the bolt face, lubricating the case will increase action peening. The second is for people who load over pressure cartridges. There is a tiny amount of load reduction on the bolt face with dry cases, remove that, and the load is 100% on the bolt face.

Model 1893 Spanish 7x57 rifle. brought in because the owner wanted to know what caliber it was. I told him it was a 7x57 Mauser. He said the guy where he bought it said it was a .308 Winchester. I tried to check the headspace and the gauge would not work. There was a ctg case in the chamber. I used a headless case remover and discovered a headless .308 case in the rifle. He said he fired the .308 in it. He had to beat the bolt closed to chamber the round. He also said it kicked like hell. I checked the headspace and it was in tolerance. I told him to use 7x57 ammo next time. I also checked the locking lug recesses for an signs of setback and there was no sign of it. So much for Spanish rifles being soft.

It is remarkable that this Spanish rifle did not blow. I am certain the shooter would have been in sad shape had the case head ruptured. Whether or not M1893's are "soft" or not, and there are plenty of examples of "soft" M1893's, these early actions frag when they blow and they have virtually nothing that will protect the shooter from gas/brass particle release.

 

[Slamfire]

I found an ancient report on lubricated 20mm cannon cases, which incidentally put out a lot more bolt thrust than any 30 cal case, here.

I cut and pasted extracts from the report.

http://torpedo.nrl.navy.mil/tu/ps/pdf/pdf_loader?dsn=9151649

A LABORATORY INVESTIGATION OF CARTRIDGE LUBRICANTS FOR 20MM F.A.T.-16 STEEL CARTRIDGES

In the past decade tests at the Naval Proving Ground had always demonstrated that waxed ammunition was unsatisfactory. Also, it was known that the Army and Air Force had frequently encountered storage and service problems caused by the use of wax on 20MM brass ammunition. Therefore, naval procurement of Army manufactured M21A1 brass ammunition had excluded wax coatings for 20MM cartridge lubrication. Since early in the Korean War it has been naval practice to oil cartridges just prior to use '(reference -(a)).

Research at this Laboratory on dry film lubricants for cartridges, began in September 1950. In references (b) and (c), were listed the guides which were to be used in determining the value of a dry lubricant coating for ammunition.

The most important conclusion of that investigation was that a thin film of polytetrafluoroethylene (Teflon) was the most satisfactory dry lubricant coating for cartridges. This conclusion was confirmed in the NRL reports of references (d), (e), (f), (g), (h), (i), and (J).

In the past either ceresin wax or microcrystalline wax had been used by the Army as cartridge lubricants. Ammunition storage difficulties with ceresin wax films led the Frankford Arsenal to use a higher melting point microcrystalline wax as an outer coat over the "Case-Cote" varnish.

Since the use of light oil coatings over Teflon-coated guns has a beneficial effect on rate of fire, it was necessary to repeat the firing tests previously performed on all test ammunition. This resulted in a significant increase in the rates of fire. Thus, oiled brass cartridges averaged 789 rpm, oiled bare steel cartridges averaged 789 rpm, "Case-Cote" wax-lubricated cartridges averaged 820 rpm and Teflon-coated cartridges 810 rpm. However, it should be noted that these high rates of fire are not obtainable on a bare steel gun with oil. It was reported in reference (1) that oil on a Teflon coated gun with properly lubricated ammunition usually produces rates of fire 40-75 rpm higher than normal.

The more I find, the more I find out that Hatcher lied.

 

[F. Guffey]

Doug Bowser, I refer to them as slide and glide shooters, there are times their bad habits get started when a reloader takes their advise seriously, starts like this “Benchresters do it this way, or that way, therefore, that is the way we should do it”, The grease used in Slamfires post were failures in design, meaning the only way the ammo would feed reliable was to grease, the Japanese example was a copy of another design that required slick-um on the case.

Back to the Benchrester, they defend the the method and or technique under the umbrella of fire fore forming, they do not want the case to lock onto the chamber out of fear the case will stretch??? Grease prevents stretch? One of the uglist threads I did not get involved had to do with “Greasing your bullets”, my opinion, neither side understood the question. On one side the benchresters were claiming their rifles were not like the rifles used by commoners, therefore grease in the chamber is OK.

Case stretch, my opinion, with minimum skill a reloader should be able to form first then fire. Reloaders are not required to have a working knowledge of reloading, they are not required to have a working knowledge of firearms, I have fired cases in chambers with .126 difference in length between the the case (from the head of the case to its shoulder) and length of the chamber from the bolt face to the shoulder of the chamber, the case did not stretch.

Between the chamber and case, I want air, nothing but air, clean air, not a lot of air but I want a little air, air (space) between the case body and chamber must escape when the case expands air is a fluid, air will flow, air can be compressed, grease/lube is a fluid, fluid will flow, a fluid can not be compressed, fluid is a solid. All I want between my case and the chamber is air.

Bolt thrust, it is about the .7854 thing. Greasing bullets/cases is an option? I am building a couple of benchrester type rifles, before I finish I will know the length of the chamber before I form cases, I am a form first then fire type shooter, most are fire to form type shooters, and still they make wild guestimates when adjusting the die to or off the shell holder.

F. Guffey

 

[F. Guffey]

“The more I find, the more I find out that Hatcher lied”

Again, I claim to have never read Hatcher, it affords me the luxury to disagree. Hatcher became a wildcatter/case former, he did not measure before and again after. He knew a case would not stretch .080”, 80/1,000, 8/100” ‘of an inch’, the guys that claim to have read Hatcher said he progressively move the shoulder forward in an attempt the increase the length of the chamber from the bolt face to the shoulder. He assumed the cases were stretching, he never considered the case was getting shorter, he did not realize the shoulder shoulder on his 30/06 cases were not moving, he did not know the shoulder was being erased and becoming part of the case body, he did not realize his new shoulder was formed from part of the old shoulder and part of the old neck.

Move forward a bunch of years, a rifle was built, the builder chambered a round, pulled the trigger and the case head blew off, the rifle was a 03 Springfield, the rifle was built with a shorter chamber than Hatchers new creation, the 30/06 Hatcher Modified. Both rifles were 03s, anyhow I informed the builder I could have told him before he left the shop what was going to happen, I told him I could have fixed the problem long enough for him to fire form his cases had I met him at the range. Hatcher did not have case head separation when he moved the shoulder forward .080” My friend had case head separation with far less difference in length between the chamber and case “WITH THE SAME RIFLE”!! if there is such a thing as all 03s being the same.

I have chambered 8mm57 ammo in a rifle that has been chambered to 8mm06, the difference in length between the chamber and case is .121” from the usual places as in from the head of the case to its shoulder and from the bolt face to the shoulder of the chamber. After firing I ejected a 8mm/06 case with a very short neck, again, the shoulder of the 8mm57 case became part of the case body and the part of the neck became part of the shoulder. Back to stretch and multi tasking or keeping up with more than one thought at a time.

F. Guffey

 

[Gunplummer]

I can give you another example of oiling ammo. I was working with some Germans at the tank range and checking out a modified MG-42. In the turret is thousands of rounds of ammo linked together. They (Tank crew) pour oil over the belts to keep it feeding right. If you ever heard a .308 MG-42 you know why they oil the ammo. This gun uses a different type lockup.

When it comes to added thrust against the bolt of a locked rifle, I do do believe it increases as the chamber gets more of a polish or has additives to make it smoother.

 

[m16tackdriver]

The stupidity of some people is simply mind boggling. He is lucky he was not blinded or worse.

When I reload I start with virgin Remington cases. Since I have both an A2 and M4, I designate which cases go with each rifle. I take a Dremel and make a small notch in the rim of the cases for the M4 so they are easily distinguished from the A2 cases when I pull them out of the brass tumbler. And when reloading all I resize is the neck. After about 4-5 reloads I check the OAL and trim it if necessary.

 

[Gunplummer]

Guffy

Did something like that with a 6.5 Arisaka once. I had two identical rifles with me at the range and one I had re-cut to 6.5x55. I felt less recoil and thought it was a light load. I jacked it out and when it rolled on the table, it looked it lost part of the neck. I was lucky because the case diameter right in front of the head had swelled to 6.5x55 dimensions. The whole case was paper thin. I never put two different boxes of ammo on the table after that.

 

[Mike Irwin]

Slamfire,

I'm wondering if your examples of using automatic weapons to show that oiling cartridge cases is not a problem isn't flawed. In an automatic weapon heavy bolt thrust is expected and is designed into the gun as the case will start unchambering while chamber pressure is still quite high.

The reason those weapons that you listed HAD (yes, HAD) to use oiled cartridges? Because the Austrians, Italians, and Japanese never really quite figured out that a slow primary extraction was necessary to avoid ripping the head off the case as it left the chamber.

US, Britain, Germany, and most other nations designed their weapons to include that initial slow but powerful extraction to break the case free of the chamber and extract it in one piece.


I also take some exception to your claim that reduction of friction through case oiling leads only to a negligible increase in bolt thrust.

I'm still looking for the report, but somewhere on the web is a relatively recent (last 30 or so years) military report on bolt thrust which shows that lubricating the case can increase static bolt thrust by up to 50%.

It may have been a NATO report, as their standard armaments testing includes as part of the protocol test firing with oiled cases and measuring the bolt thrust.

Also, I don't believe that there was any "tincan ammo coverup."

Cold welding of the bullets into the cases was known to be an issue soon after adoption of Many millions of these rounds were fired in military training and exercises with virtually no issues, even with low-number Sprinfields.



"The more I find, the more I find out that Hatcher lied."

Hum... I'd have to say that, given what you're finding, and how those findings have virtually no bearing on the discussions that Hatcher included (semi or full auto) regarding BOLT action rifles, the more you find, the more you find that really isn't germane to what Hatcher found, so that's a pretty off-base comment.

 

[Slamfire]

Also, I don't believe that there was any "tincan ammo coverup."

Cold welding of the bullets into the cases was known to be an issue soon after adoption of Many millions of these rounds were fired in military training and exercises with virtually no issues, even with low-number Sprinfields.

This is too big for one message, so let me address Hatcher and Hatcher's Notebook.

I think you are in error about the general issue of tin coated bullets. Per Hatcher’s Notebook and Naramore's Handloader’s Manual, the tin can ammunition was withdrawn after the National Matches.

If you read Hatcher’s Notebook, you see that way back in 1920 the Army was having problems with their un safe at any speed single heat treated receivers and their poorly made wartime ammunition. In stead of admitting that they paid good taxpayer money buying awful ammunition and then issued it on the firing line, they decided to blameshift this issue on the civilians. Shooters at the time were greasing their bullets to eliminate bullet fouling. They had been doing it for decades. The Army ran some bogus tests and “proved” the grease was causing the rifles to break.

In 1921, the Army used tin as a bullet coating, to eliminate bullet fouling, and the tin cold welded to the case neck and created a bore obstruction. Shooters were still using greased bullets and the Army totally ignored the cold welding and blamed blown up rifles on bullet grease. Hatcher wrote a very long section in his book, “Hatcher’s Notebook” passing all the blame to bullet grease and civilians. Hatcher never really said that lubricated cartridges were bad, but he sure repeated the Army line that greased bullets were dangerous. The theory was grease is incompressible (true) and pinches the case neck, (not true) and causes pressures to climb. The false assumption is that the grease stays put, but in fact, it moves.

I believe Major Naramore to be an honest reporter, there is none of the finger pointing misdirection at the civilians that you find in Hatcher’s Notebook. Major Naramore is clear and distinct, tin caused the bore obstruction. If you read “Handloader’s Manual”, published 1937, author Earl Naramore, page 158, you come across this section:

The ammunition made a Frankford Arsenal for the 1921 National Matches had bullets heavily plated with tin. This ammunition was satisfactory when first loaded. Tin has an affinity for brass and in this ammunition the tin combine with the insides of the case necks, forming a union between the bullet and the case just as though the bullets were soldered in place. This union is so strong that it is impossible to extract the bullets and if the ammunition is fired, dangerous pressures will develop. Most of this lot of ammunition, the only one so loaded, has been shot or destroyed, but anyone running across any of it should destroy it or preserve it only as a curiosity in the development of ammunition . It should be under no circumstances be fired. The markings on the case heads is, F.A. 21-R.

You would think Hatcher would have been aware of this, as on the frontpiece of the book, Lt Col. Julian S. Hatcher is given credit for the book sketches.!

At least five M1903’s were blown after the 1921 matches up with FA 21R. Three were double heat treat rifles and two were single heat treat. You would think Hatcher would have been aware of this as these incidents are recorded in his book!

If you have ever read the bio’s put out on Hatcher, not only was he the head of the Ordnance Corp, he visited Switzerland, shot in Switzerland, and undoubtedly got to shoot and examine their service weapons.

The Swiss had been greasing their bullets for decades. I don’t know how far back it goes, might have been since 1888. You can find claims that the grease ring increased accuracy, but they stopped greasing bullets around 1984 because the grease caused difficult extraction in cold weather.

You would think Hatcher would have seen this ammunition, but regardless, is Hatcher right, do greased bullets dangerously raise pressures and the Swiss, who fired millions of these things, just never noticed their rifles blowing up?

Incidentally, the American Rifleman had a dope bag article on greased bullets in the 60’s or 70’s. They mentioned the Austrians greased their steel service rifle bullets back in the 1890’s and noted that Parker of England was still selling “never nickel” grease in a 1969 catalog.

So, the main point is, are greased bullets dangerous, as Hatcher said?

 

[Mike Irwin]

I'm familiar with Hatcher's Notebook and the issues with the cold welding of the bullets. I've not read it in some years, but as I recall it Hatcher notes that, due to the cold welding issues, it was know that chamber pressures were increased and that is why bulletins were issued to ALL National Match shooters telling them NOT to dip their bullets in grease.

As Hatcher also notes, and as is apparently still backed up my Army records, the only issues at those matches were with shooters who ignored the issued bulletin and greased their bullets.

So...

Known issue with higher chamber pressures with tinned bullets, but no known rifle problems in military service.

Issue revealed to National Match shooters in a bulletin.

Bulletin tells shoots that, because of the known issue, bullets should NOT be greased.

Some shooters ignore bulletin and have rifle issues. Apparently no one who abided by the bulletin had issues.

I don't see anything of a coverup there.

As for withdrawing the ammunition -- I don't call that a coverup, I call that a prudent move given the demonstrated failure of some shooters to abide by the warning bulletin.

The only "finger pointing" I see in Hatcher's notebook is that which is RIGHTLY placed on those shooters who read the bulletin and, in effect, said "Consarn it, I dab dub dun do knows bettah than this har Armee fella! He ain't but not know nuttin about shawtin! I been dipping mah bullets since ah wuz a lad, mah pappy dipt his bullets, and his pappy done dipt his bullets!"

So, sorry, I dont' buy your contention that "It's all Hatcher's/The Army's fault."



"So, the main point is, are greased bullets dangerous, as Hatcher said?"

You know, I distinctly remember Hatcher not saying that greased bullets are dangerous. He even said that it was a common practice to prevent fouling.

I do, however, remember Hatcher saying that it was a dangerous practice when combined with bullets that had cold welded into the cases.

That's what the entire bulletin issued to the National Match shooters was about.

Unfortunately, I'm away from home this week, but I'm going to have to dig out my copy of Hatcher's notebook and re-read this section.

 

[Mike Irwin]

Oh, final question.

Regarding the Swiss and their greased bullets...

Were those bullets coated with tin? (No, they weren't).

So, in other words, the Swiss were greasing their bullets but were in no way recreating the issues that caused rifle failures at the National Matches.

 

[Slamfire]

Millions of moly lubed bullets have been fired in rifle matches and never a pressure problem reported. I have dipped hundreds of 303 Bullets in axle grease to reduce bullet fouling, and reduce fouling it did and my Enfield is doing just fine. as stated earlier, British shooters were greasing their bullets for decades, as they were buying the same sort of "never nickle" grease that Americans had used before the Military banned the practice.

Hopefully the greased bullet discussion will be nearing an end, but Hatcher’ Notebook and Townsend Whelen are the ground zero of the concept that lubricated cases are dangerous.

Townsend Whelen was in charge of the manufacture of the tin can ammunition, and as a man who would not publically admit to making a huge mistake, he spent the rest of his life scapegoating grease and oil on cartridges. Gunwriters, who are at best are Journalism majors, take this at face value, amplify, extend it, created a fantasy world around the concept. I like Dick Culver, but here, he has created a morality play about the evil, stupid people who greased their bullets. http://www.odcmp.org/1101/can.pdf This scape goating has been going on in the American press since Townsend Whelen retired and Hatcher put out his Notebook.

As for the 50% increased thrust number, love to see a technical report on that. I do know the American Rifleman had an article on the British Lubed cartridge proof system, perhaps an amplification of that?

Hatcher never blamed lubricated cartridges in service rifles, it was all about greased bullets.

Read the front of Hatcher’s Notebook about his experiences testing early semi automatic service rifles. He personally shot or oversaw service rifles that had oiling pads or used microcrystalline wax as a cartridge lubricant. The most well known was the Pedersen rifle.

There were several factors that doomed the Pedersen rifle, the major one was the cartridge, it was not a 30-06, and the microwax.

I am unaware of any other service rifles that used lubricated service rifle cartridges before the advent of steel cased ammunition. And as I have said earlier, fluted chambers removed the need for case lubrication in blowback actions.

However, the US experiemented in the 50’s with Teflon coatings in 30-06 and 45 ACP ammunition. In the Sept 1973 American Rifleman Dope bag pg 84, there is a picture of a Teflon coated FA54 30-06 ball round. The Army had used steel case ammunition in WW2, that had a zinc chromate coating which caused extraction difficulties. So in the 50’s they are coating steel cases with wax, Teflon, other materials to reduce the friction between case and chamber. From what I heard, the cost of the coatings was more than the savings, and the US military decided to keep using brass cases.

Small arms development was a minor issue, dollar wise, in the 50’s. From what I have seen in terms of reports, the major money was being spent on 20mm cannon development. The good old 50 caliber browning could not put enough lead on target to ensure destruction of jets. You will see report titles, such as the one I posted, experiments to lower the cost of 20mm brass cases and get the cyclic rate up.

This is a report from the period, the title is on DTIC but not the test. Would make interesting reading if I could find it.:

TEST OF TEFLON AND MICROCRYSTALLINE WAX CASE-CHAMBER LUBRICANT APPLIED TO BRASS-CASED 20MM AMMUNITION , DIEWERT,JACK R , ABERDEEN PROVING GROUND MD ,Report Date: 01-Dec-1954

As for analytic evaluations of case lubrication, go to Varmit Al. Look at his analysis. http://www.varmintal.com/a243z.htm Notice at the end of it, what is worse, increased bolt thrust due to lubrication, or stretching of the case head because the chamber is dry?

Let me also recommend a visit to Mr. James Boatright’s site “The Well guided bullet”
http://www.thewellguidedbullet.com/mechanical_studies.htm

A bunch of interesting articles under mechanical studies, one of which is:

Yielding of Brass Case Walls in the Chamber A Technical Note 30 June 2009 James A. Boatright

As a footnote:

There are two ways which lubricated cases could cause problems. The first are bottlenecked cases with too much headspace. A case with excessive headspace is going to peen the bolt face, lubricating the case will increase action peening. The second is for people who load over pressure cartridges. There is a tiny amount of load reduction on the bolt face with dry cases, remove that, and the load will be 100% on the bolt face. But the real answer to that is not to load over pressure ammunition.

And one more. You need case friction with blackpowder cartridges. BPCR competitors stick a tube in the barrel and blow, to keep the fouling moist. Blackpowder shooters have reported that with slick cases (due to breath moisture) the cartridge case is pulled up the barrel! Maybe their crimps are so strong that the crimp stretches the case up to the throat.