.303 british cases cracking 1/2 inch from case head

.Ben

.Ben

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loading .303 British, my brass keeps cracking around about 1/2 inch up from the case head, looks like a case head separation except it doesn't crack all the way around. this never happens with factory ammo and usually occurs on the first reload of the brass

I heard .303 is bad for this, anything im doing wrong or can do to stop this, and is it unsafe to shoot if the brass keeps cracking? visual inspection before loading doesn't show any visible imperfections in the brass then it comes out cracked after firing. if its still safe to shoot I have a few hundred cases that look fine that I would like to be able to make use of even if its just 1 load left.
 
These case separations almost invariably result from the cases having been fired in a rifle with excess headspace.
Were the rounds fired in your rifle, or were they acquired as once fired?
Anyway, use a hacksaw, and section the case head. Dollars to donuts, you will find a groove inside the case, an incipient separation.
Cases can be fireformed to a rifle, and then loaded so that they headspace on the rim.
Or, get the headspace checked.
Even then, fireforming is a good idea. Use a little o-ring, ponytail ring, etc., around the case in front of the rim, to set the case back against the boltface for first firing. Do not FL size.

I acquired a couple of sandbags full of brass fired in Gov't. issue rifles. Cull rate, sorting out cases with incipient separations, ran about 20%.
 
The military chamber on the British Enfield rifle is fatter and longer than American made cartridge cases and reloading dies. When these "civilian" designed cases are fired in a military chamber they stretch badly. This is because at maximum military headspace you can have approximately .016 head clearance or air space between the bolt face and the rear of the case.



If you fireform your case and let the case headspace on the shoulder and not the rim the cases will not stretch.



Below is a Wilson case gauge designed for measuring SAAMI civilian ammunition case length fired in a "smaller" civilian chamber. The amount the case is sticking above the gauge is how much longer the military chamber is than our "civilian" .303 resizing dies we use. Bottom line, with SAAMI dies this is how much too far we push the shoulder of the case back when we should just be using a neck sizing die.



Guess where Remington puts the shoulder of the case on its new brass.



Buy a Lee Collet neck sizing die and a case forming and trim die, the case forming die can be used as a shoulder bump die when you cases start getting hard to chamber. The case forming die will only touch the shoulder of the case and in the photo below I'm holding the case in the die with my little finger to keep it from falling out.



A small rubber o-ring can be used for fireforming your cases, the o-ring holds the case against the bolt face and centers the rear of the case in the chamber to get better case alignment with the bore and accuracy.



I fireform my cases with reduced loads using .312 pistol bullets.

 
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Below is a factory loaded Winchester case fired in my Enfield and the headspace is set at just under .067, this case stretched .009 on its first firing.



Below a RCBS Case Mastering Gauge used for checking stretching and thinning in the base web area of the case.



Bottom line, the trick to long .303 case life is proper fireforming and not letting the case stretch when fired. ;)

Below is the worst type headspace you will ever encounter, it is mostly found in dimly let bars and is caused by unscrupulous bartenders.



Laugh2
 
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wow, great info guys, ive never tried fireforming so I will have to give it a go.

also I was FL sizing every time, ill have to order a neck sizing die.

that graphic seems to show exactly what is happening to me.

I must ask again however, is it unsafe to have the case crack?
 
Case head separation *is* dangerous. You've venting xxK PSI gas into the action which in turn can escape onto the operator,
depending on how well the action is designed.

ht tp://www.exteriorballistics.com/reloadbasics/caseinspect.cfm

Excerpt:

"In extreme cases, the head may actually separate from the case body, leaving the forward portion stuck tightly in the chamber. This is an extremely serious and potentially dangerous condition that may result in serious injury or the destruction of a fine firearm. This is normally caused by a condition related to “headspace,” or more accurately, excessive headspace."
 
.Ben said:
I must ask again however, is it unsafe to have the case crack?
Click to expand...

Your .303 British cartridge case is designed to hold and "contain" 46,000 cup or 49,000 psi and push the bullet down the barrel.

A cracked case or a case head separation could send hot high pressure gasses back in your face.

Below from left to right, new unfired Remington case,(note location of shoulder) center-once fired Winchester case, far right- Winchester case fired three times and full length resized each time. (over resized)



Some food for thought below, so don't be stupid and toss any brass that not 100%. Escaping high pressure gas is nothing to fool with. And remember what happened below could be your face and safety comes before all else when reloading.

Guy Blows His Thumb Off by Holding His Revolver Improperly

http://www.borasps.se/loads/460xvr_accident.htm
 
Excellent information, well explained with clear illustrations. It has taken me years to put this together on my own from bits and pieces of info picked up here and there. Good on you and many thanks.
 
I never fire .303 British without a broken case extractor handy. I bought one off eBay for $10 a while ago and have had to use it a few times. Since using the o-ring method I haven't had to use it yet though.
 
Duplicate of a post I just made on another thread in this forum on this problem.

I think ED has the situation thoroughly under control, but this is just another point of view on the same problem.

Hope this helps. (Hi, Ed!)

The whole idea behind the O-ring trick (I use pony-tail ties: cheaper) is so that you can fire anything in the rifle and then reload it TO FIT THAT RIFLE PERFECTLY BY NECK-SIZING ONLY. The cases now headspace on the SHOULDER, as with rimless ammo.

Service ammo for the .303 was VERY carefully regulated: rim thickness was .059" Min and .063" Max. Rims were BEVELLED to aid feeding. There is NO .303 commercial brass made anywhere in the WORLD which is to Military Spec. Likely Partizan is closest. I use DEFENCE INDUSTRIES brass: Canadian War 2 brass, best brass ever made for a .303. Headstamp DI Z and the Year (1942 through 1945).

Headspace on the RIFLES was controlled through CAREFUL fitting of the Bolt-heads. Min was .064", Max was .074". Worked wonderfully with good MilSpec ammo.

THERE IS NO GOOD MILSPEC AMMO ANY LONGER. I have seen commercial ammo with rims as thin as .040": automatic .023" EXCESS headspace, even in an absolute-minimum Rifle. It goes bang, separates after 1 reload. Most of it is not THAT bad but, with th O-ring trick on FIRST firing, it can ll be reused.

The KEY is SEGREGATION of your brass, by the Rifle it was fired in. In combination with th O-ring trick, this will give you brass which fits any SPECIFIC Rifle perfectly, can be reloaded up to and beyond 30 times..... and turns in Match-grade performance.... but you MUST keep it segregated. Load it with a Lee Collet Die for best performance.

Switching ammo about, all you can do is size for the smallest chamber, hope and pray.... and be ready for less-than-excellent accuracy and short case life.

Remember this point: over the years, the Army bought 10 million .303 rifles and they paid for them in GOLD, an average of just over an ounce per rifle. If you TREAT it and LOAD for it like the $2200 rifle it actually IS (by modern standards), you will get the best out of it..... and a Barrel thrown in which will outlast almost ANY modern barrel.

WORTH taking a bit of care, one would think.

Hope this helps.
 
WhelanLad said:
worth doing this o ring trick for a ruger no1 brit?
Click to expand...

That depends on the rifles headspace settings and your rim thickness.

Below is the cheap bastards headspace gauge.

1. Measure the length of a new or full length resized case and write the length down. A resized case must have the shoulder bumped back far enough so that the case does not headspace on the shoulder of the case and allows the rim to contact the chamber.



2. Next using a spent fired primer push the primer into the primer pocket with your fingers just starting the primer.





3. Now slowly chamber this test round allowing the bolt to seat the primer and the remove the case. Now re-measure the test case and write it down. You have just measured head clearance and the amount of primer protrusion from the rear of the case.

4. Now subtract the first case measurment from the second and write it down. This will be your head clearance or the "air space" between the rear of the case and the bolt face.

5. Now measure your rim thickness and write it down.

6. Now add the head clearance measurement and the rim thickness measurment and this will be your actual headspace.

Example: .009 + .058 = .067



Military headspace is .064 to .074
Commercial headspace is .064 to .067

To answer your question if the headspace is large enough to fit a small thin rubber o-ring "WITHOUT" making the bolt hard to close you can fireform your cases using this method.

BUT please note you should grease your locking lugs when doing this to prevent wear on the lugs.
 
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