British pressure and a soup sandwich

[Edward Horton]

Jim K

Our American .303 brass falls apart too soon when reloaded and I read that American factory ammunition is loaded to below 43,000 CUP.

Our Enfields are stamped with a normal working pressure of 18.5 tsi or 41,400 CUP, I have also seen 19 tsi, 19.07 tsi and 20.71 tsi listed as the operating pressure of the Mk.VII or Mk.7 round.

Our American reloading manuals list the max chamber pressure as 45,000CUP or 49,000 PSI transducer method, if our American made cases are rated by the factory for 18.5 tsi or 41,400 CUP this explains why the cases fall apart at the higher pressures.

SOME people blame the Enfield for having a weak action when our American brass cases appear to be the main cause of the problem.

[Parashooter]

I'm not sure it's accurate to assert that all US-made .303 cases are likely to come apart prematurely when fired with full-power loads. Recently I made a test to see if I could reproduce Ed's results with Winchester cases and maybe shed some light on the failure mechanism.

I first selected two W-W .303 cases that weren't brand new, but showed no signs of stretching or thinning. (I normally shoot my .303's with fairly mild cast-bullet loads that don't produce enough pressure to stretch cases.) Then I reloaded and fired one of them until it separated, made one small change in firing preparation and loaded/fired the other one until I got tired of the experiment.



Upper case was collet-die neck-sized, reloaded, and fired 10 times in excellent-condition Lithgow SMLE with 180-grain bullet over 41 grains of RL-15 (1 grain under "maximum" per Alliant website data - MV 2450 fps). Case elongated from 2.210" to 2.222" in five shots, was trimmed back to 2.210" and separated on 10th shot. (Case body was stuck so firmly in chamber that chamber cast was needed to remove it - and it still didn't budge until the cast has been driven about 1/4".)

Lower case, from same batch, has been reloaded and fired 15 times with same load in same rifle. Its length has remained at 2.210" - with zero elongation and no internal or external signs of stretch.

The difference? Upper case was kept clean and dry throughout test - lower case received a very thin application of castor oil before each firing. Because the forward portion of this case was prevented from adhering to the chamber walls, the stretching and thinning I observed with the first (dry) case didn't occur at all.

One possible conclusion from this exercise is that the combined bolt compression and receiver elongation inherent in the rear-locking SMLE action (not "weak" but simply a bit more flexible than front-locking designs of similar mass) was enough to allow the case head to back out approximately .002" with each shot at this pressure (cumulative .012" elongation for 5 shots, dry). Since chambering didn't become increasingly difficult during the test, I conclude that, once pressure dropped, the elastic bolt and receiver returned to their unstressed dimensions with enough force to push the case back into the chamber, restoring the head/shoulder dimension by moving the relatively weak shoulder, while the stronger area immediately ahead of the solid web remained in the stretched/thinned condition it acquired at peak pressure. Consequently, each shot effectively lengthened the neck - at the expense of thickness near the head. With the lubed case, no stretching occured since action flex just moved the shoulder back and forth.

While it's well-established that lubricated cases allow more force to be transmitted to the bolt face than do dry cases, studies quantifying the difference are rarely cited. According to one impressive-appearing modeling exercise (at Rifle Chamber Finish & Friction Effects on Bolt Load and Case Head Thinning Calculations done with LS-DYNA ) the calculated difference in peak bolt face load between a greased case and a dry case in a smooth chamber is about 10%. If this model is accurate, the difference is barely significant and is in fact less than the normal acceptable variation in peak pressure within a fairly small sample of identical loads.

Whether or not any increased wear on the rifle action resulting from the added load caused by lubricated cases is more important than cartridge case longevity is an individual judgment call. I believe that with sufficient care (and moderate powder charges), lubed cases can provide a practical alternative to premature separations that may be useful for experienced handloaders who understand the risks and benefits. Many respected sources disagree.

[Edward Horton]

Mr. Parashooter

With all due respect to you knowledge, experience and wealth of information you have shared with us all of us on the internet some people sometimes look at a problem from a different angle and perspective.

I have used the resizing lube method in the past with many different caliber cases, but if you remember what Peter Laidler said about why the Enfield bolt heads only go up to #3 because by that time the case hardening has worn through and the Enfield Rifle should be sent for overhaul or scraped because of receiver wear.

Mr. Parashooter my first Enfield came from Turkey and never had a trained British or Commonwealth armourer even look at it, I have never been worried about what you and I can do with resizing lube, I’m worried about what the brain dead Joe Shmuck does who has no experience or common sense.

If the “inherent weak design” theory held water my Remington 788 in .243 with rear locking lugs and my 30-30 Winchester with its rear locking would have had case separations also, I still think the problem lies with the design and pressure rating of our American made .303 cases especially when people have reloaded their Greek HXP case over 30 times.

If the person who fabricated the special bolt head below to make up for the pounding the Enfield receiver had taken over the years, what do you think the added bolt thrust from oiled case would do to an already worn receiver.

If this persons fired cases had the primer backing out this far with a #3 bolt head what shape do you think the receiver lug recesses were in and what would even more bolt thrust do to this rifle.

The Canadian at the old Jouster site had a fantastic idea with the rubber o-rings and fire forming cases without any oil or lube.
(And bolt thrust is another word for pounding, slamming, bashing, etc, etc)

Fire Forming Cases W/Zero Headspace - Gunboard's Forums

And a little about bolt thrust.

http://www.realguns.com/Commentary/comar52.htm

Ackley Bolt Thrust Tests. « GunsmithTalk

[Parashooter]

"If the “inherent weak design” theory held water my Remington 788 in .243 with rear locking lugs and my 30-30 Winchester with its rear locking would have had case separations also . . . "

The 788 has a significantly fatter bolt and heavier receiver walls than the SMLE, meaning there is more mass of steel to resist flex. The .30-30 cartridge operates at significantly lower pressure (38,000 c.u.p.) than the .303 - with less pressure, there's less flex. I've never believed or said the SMLE is an "inherently weak design" - since it's plenty strong enough for its original purpose. But I am reasonably certain by now that a normal 45,000 c.u.p. shot shoves the bolt face some .002"+ to the rear at peak pressure. Combined with any cartridge end-play present before firing, this small amount of flex eventually causes separation in reloaded cases unless something (like lube) prevents them from adhering to the chamber walls.

Regardless of the results with lube, my dry W-W case survived 9 shots at about service pressure and velocity before it separated on the 10th shot. (If this weren't a destruction test, I would have scrapped it after the 7th shot when the first external signs of incipient separation appeared.) For my money, that's acceptable performance indicating no inherent weakness in either the Winchester brass or the Lee-Enfield in which it was fired.

I don't doubt that some .303 cases are significantly heavier than these and would survive longer use with heavy loads - but I don't think this batch of W-W .303's performance substantiates a broad assertion that "Our American .303 brass falls apart too soon when reloaded. . . "

As for worrying about "brain dead Joe Shmuck" - if he's that bad, we should probably persuade him to take up golf before Dianne Feinstein has a chance to use him as a poster-boy for gun control. I sure don't want to limit our discussions to a level he can understand.

[Edward Horton]

I don't doubt that some .303 cases are significantly heavier than these and would survive longer use with heavy loads - but I don't think this batch of W-W .303's performance substantiates a broad assertion that "Our American .303 brass falls apart too soon when reloaded. . . "

Mr.Parashooter

I can tell you this, the box of 500 Winchester cases I bought at midway are the worst batch of brass I have ever reloaded, (They could be just a bad batch of brass from a company that went bankrupt)

BUT judging these and other American .303 cases I believe the cases are designed for pressures less than 43,000 CUP because this is what our ammunition companies are loading them to because of the older Enfield’s still being used.

And remember the 18.5 stamped on the Enfield Rifle is the normal operating pressure and that is 41,400 CUP and I’m thinking the ammunition companies are making our .303 cases from the same batch of brass they make the 30-30 cases from.

I will not argue with you about lube or oil in the chamber other that to say an oiled proof round was used to seat the bolt lugs and bolthead and bolt thrust is governed by chamber pressure and the size of the cartridge head and shape of the cartridge.

Also it was "brain dead Joe Shmuck" that said the pressure difference between the .308 and 7.62 was over 10,000 PSI and you can’t shoot them in the same rifle.

[Parashooter]

Just a couple of minor points, Ed.

It was U.S. Repeating Arms that went belly-up. The Winchester ammo operation is a different animal and still going strong as a division of Olin Corp. From the website at Olin -

"In December, 1980, the company's board of directors authorized the restructuring of the Winchester Group to allow Olin to better focus more of the company's resources on Winchester's sporting and defense ammunition business. With this restructuring, Winchester's U.S. sporting arms business, which had been part of the company for nearly half a century, was set up as a freestanding operation. In July, 1981, it was sold to the U.S. Repeating Arms Company in New Haven, Connecticut . . ."

18.5 tons is a British base-crusher number, not to be confused with US-style radial-crusher "CUP" figures. There's about 10% difference according to good sources we've both seen. Add 10% to 41,400 and we have 45,540.

Joe says a lot of dumb stuff - that's the danger of "democracy", every Schmuck gets a vote around here. Personally, I tend to favor the Darwinian approach and just hope Joe doesn't hurt innocent bystanders while he's removing himself from the voter rolls.

[Edward Horton]

Parashooter

Someone might have forgotten how to make brass cartridge cases or the bean counters took over quality control, read below.

The Winchester/Olin we knew of old died along with DuPont IMR reloading powders, Winchester ball powders are made by a company in Florida and Remington/Dupont IMR powders are now made in Canada. Only the names have survived and Winchester and DuPont/IMR powder is now part of General Dynamics.

Winchester-Western (Winchester Powder is now supplied by Hodgdon. )
IMR Powder Company (now a division of Hodgdon Powders 2003)

http://www.reloadammo.com/rel-powd.htm

MSDS

Alliant powder is now running the Lake City Arsenal and manufacturing ammunition for the U.S. Military, Alliant powder is part of ATK ATK - A Premier Aerospace and Defense Company

ATK Armament Systems

ATK provides ammunition systems solutions through ATK Armament Systems, the nation's largest producer of commercial and military ammunition and a leading provider of gun systems, propellants, and advanced energetics.

Major Products and Programs — Military
• Small-caliber ammunition
• Medium-caliber ammunition
• Medium-caliber gun systems
• Propellants for tank training and tank tactical rounds
• Environmentally friendly ammunition
• Propellants for ammunition and tactical rockets
• Propellant for Modular Artillery Charge System
• Management of Lake City Army Ammunition Plant and Radford Army Ammunition Plant
• Electronic and fire-control integration
• Military tactical accesories

Major Products and Programs — Commercial

• Alliant Powder for reloaders and ammunition manufacturers
• CCI, Speer, Lawman, and Blazer ammunition; Speer bullets for reloaders
• Champion traps and paper, metal and clay targets
• Federal Premium, Fusion, and Estate Cartridge ammunition
• Gunslick and Outers gun care products
• Shooters Ridge rests, gear bags and speed loaders
• Ram-Line replacement stocks
• RCBS reloading equipment
• Weaver mounting systems
• Eagle Industries law enforcement tactical accesories


We now have ATK as top dog and General Dynamics as the second place looser and it is my understanding ATK group is the biggest and largest manufacture of ammunition in the U.S. Only the hollow shell of the names remain of Winchester and Remington/Dupont/IMR and some of the IMR powder line has been replaced by ADI Australian powders.


Now tell me to trust the Military Industrial Complex and American made .303 cases.

There is NO printed data stating we have a 10% fudge factor in converting long tons to PSI.

[Parashooter]

"There is NO printed data stating we have a 10% fudge factor in converting long tons to PSI."

Really? This is from a web page you referenced earlier in this thread -

"In Britain, a third set of crusher standards were developed, using a "base" crusher. . . The units were generally stated in British long tons per square inch, or tsi. Pressures indicated by this method run 10 to 20% below those indicated by radial crushers."

I'm afraid you've gotten confused between Winchester ammunition (including cases) and Winchester powder. Same name - but different products, manufacturers, corporate affiliations, and marketing/distribution channels.

[Bindi2]

New winchester cases in plastic bag 50 in number. Rifle a No5 with an 0 bolt head in spec first head separation 2nd fireing neck sized only. The brass is such poor quality it dose not thin it just parts. Case capacity of this stuff new is way higher than any other well used cases i have. I also neck 303 cases to 243/303 not with this rubbish.

[jeff]

If you have a separated case you need one of these, top one is a 303 then 7.62 and finally a 223 with a split case..