One thing that it says is that a well-oiled chamber or a brass case with lube still on it may cause difficulties in extraction
That is a bunch of horse-hockey. Those that adhere to this are just perpetuating an Army coverup from 93 years ago.
The Army Ordnance Officer’s who wrote for the American Rifleman created a bunch of errors that have never worked their way out of the American shooting community.
Greased bullets, greased cases, and oiled cases is one of them.
Way back in 1920 the Army was having problems with its single heat treated receivers and poorly made ammunition. So they decided to blame the civilians. Shooters at the time were greasing their bullets to eliminate bullet fouling. The Army ran some bogus tests and “proved” the grease was causing the rifles to break. The Army made the claim that the cartridge had to cling to the chamber and reduce the load on the bolt or the action would break. Maybe true in single heat treat Springfields, which are dangerous with any load, but this claim is bogus because firearms are designed to carry the full load of the cartridge, case friction is totally ignored.
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.
Townsend Whelen, the officer who made the tin can ammunition, did the same in his books, but he added that oil on cases is dangerous.
Over the years the idea that cases have to “cling” to the chamber have been amplified, modified, etc, all of it ignorance and superstition.
Incidentally, oil may be incompressible, but it flows. Same for grease. If oil did not flow the cylinder heads on my vehicles would have blown long ago and my wheel bearings seized.
A number of sucessfully fielded pre WWII guns used oilers to reduce breech friction. The Swedish Ljungman was one:
http://www.surplusrifleforum.com/viewtopic.php?f=47&t=11436
OK, here we go. Lots of so called "experts" are going to jump on this. These rifles, the Jlungmans AG-42B types, were made to have the brass cases lubricated. I know this flies in the faces of many of our members who think they know better, but it is true. The Swedes used a very well made,semi-thick oil that was rubbed onto the loaded ammo to aid in extraction. As you know, the brass cases if left dry may or may not extract, tear in-half or get crushed in the action by that "killer" bolt.
I use a product that I have had very good luck with. Bordens " Slide-All" It is a dry film lube that seems to work very well. Now, my full house loads do not tear in-half. Extraction/ejection is normal ( if you call 25 yards normal) and accuracy has gone way up. Life of the fired brass so far is over 5 re-loads. I'm not too keen on sharing my loads as these rifles are very temperamental with hand loads. I do use a 140 grain bullet and a "medium ' port pressure type powder such as IMR-4895 and RELOADER-15. IMR-4350 and IMR 7828 shot well after I designed and installed a gas port valve. I like the sights on the rifle and how well the rifle handles. You can't bad mouth the rifles accuracy, that's for sure.
Here's a 200 meter target from last summer.
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:
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.
XTRAXN is fluting the chambers of their AR15’s to improve function. You can look it up at
http://www.laruetactical.com/xtraxn™-technology-larue-tactical
This is a case fired in an XTRAXN chamber. You can see the flute marks
Chamber flutes and dry lubricants are why you don’t see oilers anymore and the memory of oilers has passed beyond living memory. Hatcher's Notebook is still in print and that is why this coverup still persists.
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]
The Army/Hatcher/Whelen claims that greased bullets are dangerous turns out to be totally bogus. The Swiss used greased bullets up into the 80's.
I highly recommend visiting this site and seeing a dynamic analysis of chamber finish/case fricition.
http://www.varmintal.com/a243z.htm What I want to point out is that as case friction is reduced, case stretch is reduced. If this is true, it may mean that that cases are less likely to rupture, either through a brass flaw, or through repeated firing, if the cases are lubricated.
Post WW2 the US Army and Navy were developing coatings to break the friction between cases and chambers to improve the function of machine guns. In the Sept 1973 American Rifleman Dope bag, pg 84 is a picture of a teflon coated FA54 30-06 ball ammunition.
From Army Material Command Pamphlet AMCP 706-260 Engineering Design Handbook, Guns Series Automatic Weapons. Feb 1970
Chapter 8 Lubrication of Machine Guns
8-3 Case Lubricant
Although the gun designer is not directly involved with ammunition design, he is directly concerned with handling, loading, and extracting during firing. A smooth chamber is essential for extraction and a properly lubricated case is a decided asset. The lubricant should be a dry lubricant and should be applied at the factory. Considerable effort has been made to find suitable lubricants for this purpose. Some success has been achieved but continued search is still being advised, especially since two independent facilities are not in total agreement.
The Naval Research Laboratories conducted test of brass and steel cartridge cases coated with films of polytetrafluoroethylene (Teflon). Results were outstanding in meeting required protection and lubrication properties. Laboratory results, later confirmed by firing tests, showed low friction and consequently less wear in gun barrels. Other desirable features include freedom from cartridge malfunction, no chamber deposits, decreased ice adhesion, and less chance of thermal “cook-off”. Teflon can be applied to steel and brass ammunition by mass production methods. Its protective ability permits pre belting and packaging of ammunition since no further handling prior to use necessary. Its supply is abundant and its cost reasonable. Thus the use of Teflon in this capacity seems ideal.
Aberdeen Proving Ground is more reserved in its appraisal of Teflon coating. Whether or not the techniques of applying the coatings were similar, those used at APG were not free of coating defects; a high cull rate existed. When tested with cartridges coated with microcrystalline wax, ceresin wax, and uncoated ammunition; the Teflon-coated wax showed many advantages but was also found wanting in some respects. Teflon and micro-wax had better extraction properties and Teflon left a much cleaner chamber than the others; micro-wax was second best. About 50 percent of the Teflon-coated cases had slight bulges after extraction; other types also were similarly damaged but with no apparent significance attached to a definite choice. For dusted ammunition, the Teflon and micro-wax were far superior to the other two types with Teflon having a slight advantage, although when fired in a comparatively rough chamber, Teflon was outperformed by all. Reiterating, the gun designer, aside from providing smooth sliding surfaces, is almost totally dependent on the physical properties of the lubricant to make his gun perform satisfactorily under all assigned conditions.
The last sentence is a summary of the chapter; not a comment on case lubrication alone. A copy of AMCP 706-260 can be found on DTIC.
This is on the web:
A LABORATORY INVESTIGATION OF CARTRIDGE LUBRICANTS FOR 20MM F.A.T.-16 STEEL CARTRIDGEShttp://torpedo.nrl.navy.mil/tu/ps/pdf/pdf_loader?dsn=9151649
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.
After the Frankford Arsenal learned of the NRL work with Teflon coatings for cartridges, an Army Ordnance project was established at the Proctor Electric Company to put Teflon coatings on the steel F.A.T.-16 cartridges manufactured there. However, certain difficulties arose in obtaining good corrosion resistance with Teflon, apparently due to the manufacturing methods used.
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.
LTC Chin documented the essentials of machine gun design in this Vol IV. Most people are just interested in pretty pictures of machine guns, which are in Vol I-III, but for those interested in design, Vol IV is the treasure.
The appendixes have schematic illustrations of representative mechanisms. All sorts of locking mechanism, feed mechanisms, and these oiling systems. These two pages present to designers already developed mechanisms on lubricating cartridges for machine guns.
In the text of the book, designers are made aware of the limitations of lubricants, and that lubricants were essentially designed out of the systems of modern machine guns. However, if the designer is not able to reduce the breech friction for other means, these images might help the designer to escape from the corner he painted himself into.
The use of lubricated cases have a sound technical basis. That is, to reduce breech friction.
I highly recommend everyone seek to acquire Vol IV for a better understanding of firearms design. It took me years (pre internet) and I only had to pay $150.00 for mine. And that was 15 years ago.
You can buy one from Amazon for $394.00!
http://www.amazon.com/gp/offer-listi...0897817&sr=1-5
These images are taken from "The Machine Gun", Vol IV
It is true that dry cases decrease the load on the action lugs but this is due to parasitic friction. Dry cases do not decrease radial load.
Neither the action nor the barrel are weakened assuming that the case carries any of the load. Both the action and the barrel are designed assuming zero case friction and that the action carries all of the load.
I develop all of my loads with lubricated cases, either coated in paste wax or I leave RCBS case lube on the outside. Sometimes I have dribbled motor oil or some other lubricant. This is for a number of reasons. The first is that I want to see the transition from rounded primers to flat primers developing loads. I found dry cases in gas guns always gave me flat primers. This was due to the delay it took for the case to reach the bolt face. The primer was backing out first, the dry case neck was stuck in place, then as pressure built the sidewallos of the case stretch and the case moves to the bolt face stuffing the primer back in the pocket. The end result was that the primer always looked flat regardless of load. When I started lubricating cases in gas guns I could see the transition in pressure when primers change from rounded to flat.
Also, lubricating cases in gas guns gave me outstanding case life. The cases were no longer being stretched during extraction. I took one set of 100 308 LC cases 23 firings in a M1a. I never experienced a case head separation. I sectioned cases that developed neck cracks or body splits and there is absolutely no evidence of case head separation. Cases firing in a friend’s FAL broke in less than five firings.
Another reason I lubricate cases during load development is that I don’t want friction giving me false indications of safe pressures. When a case presses hard enough against the bolt lugs you will have hard extraction. This is proof positive that pressures are too high. Sticky extraction is an absolute indication of too high of pressures, along with blown or pierced primers. Case friction will
disguise excessive pressure because the lugs are not fully loaded. When I lubricate the case I get the full load on lugs and I know when I get sticky extraction that my loads are at a maximum.
For those who are worried about high pressures there is a sure cure: cut your loads. This is so obvious but it does not register with some people.
There are some risks with lubricated cases. The first is that oil/greases pick up dirt. That is why dry lubricants like Teflon coatings were developed and are being used today. Dry coatings are less likely to attract dirt. Another problem is action peening. Action peening is a risk regardless of whether the case is wet or dry if you are shooting severely oversized cases. Bolt loading is basically an impact load and when case headspace is way below minimum you run the risk of action peening. I don’t know how much of a gap it takes, but lubricating the case will just cause more problems.
Blackpowder cases require friction between the case and chamber. BPCR competitors breathe into their barrel to keep the BP fouling moist. Competitors have told me of their cases being pulled up into the throat when they forgot to swab the chamber. One guy told me his cases had 1/10 or an inch of rifling engraving.!
I shot this group with paste wax coated cases recently. The shoulder to base dimension is not controlled in belted magnums. 300 H&H cases are very expensive and I don't want case head separations when I fire new cases for the first time. I also believe that accuracy is improved with lubricated cases because there is no case binding due to friction. The action is loaded as it was designed.
Anyway, lubricated cases shoot fine.
It shoots as good as it looks:
