Case head seperation?

[jim_k]

Pending case head separation is evident by a bright ring around the case head, at the point where it will separate, as shown in the photos above. Watch for that, not bulging. Winchester cases and Remington, are just fine. Buy a broken case extractor, and keep it in your gear. You may get a complete separation some time and need to remove the portion in the chamber. No need to spend the extra money on Lapua or Norma. They're good; maybe they're better, but not that much better.

[Arky 223]

bigedp51 that is excessive headspace.

[gunrack]

Thanks, I keep my eyes peeled. I'd like to keep my digits and eyeballs for a little bit longer.

[bigedp51]

bigedp51 that is excessive headspace.

I collected Enfield rifles and any books and manuals I could get my hands on for a very long time.

The military Enfield chamber was reamed larger in diameter and longer to the chambers shoulder in 1914. This was for two reasons, there was a political ammunition scandal over "who" was awarded contracts to make ammunition for the military. Some of this ammunition was so poorly made it was hard to chamber and the mud of trench warfare complicated the problem further.

If you can learn to reload the .303 British case and get 32 reloads with moderate pressures you will understand the word "headspace" and old surplus rifles.

My No.4 Enfield rifle below has had the headspace set below minimum just kissing the rear of the case to .010 over max headspace. Normal headspace was min .064 and max .074 and the Australians set .084 as emergence wartime headspace. And this rifle had the headspace set from .057 to .084 and I'm still here alive and well with all my body parts. Bottom line, chamber pressure, and the strength of the case have the biggest effect on your cases life. And the reloading manuals data for the .303 British and other older rifles are for the weakest link in the chain, meaning older rifles made from softer steels and weaker actions.

http://www.milsurps.com/images/imported/2009/08/IMGP13551-1.jpg

If you look at a SAAMI cartridge and chamber drawing headspace is listed as min and max with .010 in between the two. And many older milsurp rifles have headspace over maximum and measuring the base of the case above the extractor groove will let you know when you are pushing the case limits.

The link below does not tell you chamber pressure, it simply tells you the strength of the case and how much pressure it can take before you reach its elastic limits.

Simple Trick for Monitoring Pressure of Your Rifle Reloads
http://www.hodgdonreloading.com/reloading-education/tips-and-tricks/simple-trick-monitoring-pressure-your-rifle-reloads

So ask yourself "why" a new Remington 700 in 30-06 can't be loaded to .270 Win chamber pressures, its just a necked down 30-06 case. And ask yourself "why" the table below was even made up.

http://i.imgur.com/EPcuYSG.jpg

[bigedp51]

Below are fire formed .303 British cases using the rubber o-ring method. The rubber o-ring serves two purposes, it holds the case against the bolt face so the case will not stretch and thin. And when the o-ring is compressed it centers the small diameter case in the rear of the "fat" chamber. If this wasn't done the case would just lay in the bottom of the chamber and after firing if the case was stood on its base it would look like the Leaning Tower of Pisa.

http://i.imgur.com/FCHGvIZ.jpg

These cases are fire formed with reduced loads and using .312 100 grain pistol bullets.

http://i.imgur.com/HHDfGl9.jpg

And when forming 100 to 200 cases the reduced loads help make the brass butt plate "softer" and they are fun for 50 yard plinking.

http://i.imgur.com/HyLFfuv.jpg

Case forming load at lower left.

http://i.imgur.com/tyJBZe1.jpg

Bottom line, your cases will not separate if properly fire formed and resized with minimum shoulder bump. Meaning staying within the brass elastic limits and being able to spring back without stretching.

You can fire form your cases by seating the bullet long and jamming it into the rifling to hold the case against the bolt face. You can also create a false shoulder and let it hold the case against the bolt face.

Or you can fire form using the COW method (Cream of Wheat) but the firearms industry does not stand behind this method. (nor should anyone)

http://i.imgur.com/eHM6WZi.jpg

[Zero333]

The bulge can also be that the sizing die did not size that part of the case. I see this with 243w 260r 7-08r 308w and many others.

Your chamber is generous around the head and the sizing die doesn't reach all the way down the case, hence why there is a lil bulge, but it's not dangerous.

Like others said, cut a piece of brass down the middle with a dremel and check for brass thinning above the head.

[Robinhood]

If I missed any of this my apologies. Just a few questions.

Is this an aftermarket barrel? Does it have a large chamfer leading into the chamber on the barrel breach? Do you have a picture of the fired brass with bulges? Is the chamber gauge standoff more than say .150"? Have you taken a dial caliper and compared the mouth of the chamber dimension with a SAAMI chamber drawing?


Look around page 83

http://saami.org/specifications_and_information/publications/download/Z299-4_ANSI-SAAMI_CFR.pdf#page=13

Should be in the ballpark of .471 plus or minus....

[gunrack]

I shot about 50 rounds through my .243 today with new Winchester brass. I measured the headspace before and after and saw not growth in the headspace. I was below the load max stated by Sierra but still see the little ring starting to appear just above the case head.

I shot the best group I have ever shot with this rifle today. It was a four shot group that measured 0.450" with new brass. 85 grain SBT over 37.2 grains of IMR4320. Then a second best group of 0.600" with a 100 SBT over 40.5 grains of IMR4350. Best groups to date with this little bone stock savage.

[Texas10]

Congratulations, gunrack! That's good progress and definitely "minute of deer" accuracy, and the reason we love to hand load.

In case your interested, the load I've worked up in my 243 with a 22 inch, 9.25 twist "pencil" barrel is 87 grain V-Max at .012 off the lands, 43.5 grains of IMR-4831, CCI-250, and Winchester brass. Haven't quite got it completely tuned, it's shooting well, just not as well as yours.

[gunrack]

Congratulations, gunrack! That's good progress and definitely "minute of deer" accuracy, and the reason we love to hand load.

In case your interested, the load I've worked up in my 243 with a 22 inch, 9.25 twist "pencil" barrel is 87 grain V-Max at .012 off the lands, 43.5 grains of IMR-4831, CCI-250, and Winchester brass. Haven't quite got it completely tuned, it's shooting well, just not as well as yours.

I just had a good day. A minute of deer is all I really need but you know how it is. we always want them little bitty groups. I feel more confident knowing that the rifle is more capable than I when I get ready to take a shot. Days at the range for me don't happen like that very often. I may never shoot another one like that but I have put in a lot of work on loads on this little rifle. I will make a note of that load you suggested and give a shot some time. I love to tinker with new loads but it sure gets aggravating sometimes. I haven't got enough hair left to keep pulling on it the way I have been lately. LOL