Case head separation...223 caliber...

[Metal God]

I had case separations and split necks with the 6x45 until I listened to people smarter than me and molded my chamber, sent in my spent brass to Redding and had them make me a sizing die.

All the bold sections got me thinking . I don't shoot the 6x45 or even know what that is . Is it just a necked up 223 ?

Either way please explain why you were getting case/head separation that a simple die adjustment could not fix ?

How did a custom die fix the problem a die adjustment and maybe competition shell holders would not resolve ? Is this a wild cat or is your chamber that out of spec ?

What measurements were you trying for when you molded you chamber ?

[dwalker]

All the bold sections got me thinking . I don't shoot the 6x45 or even know what that is . Is it just a necked up 223 ?

Either way please explain why you were getting case/head separation that a simple die adjustment could not fix ?

How did a custom die fix the problem a die adjustment and maybe competition shell holders would not resolve ? Is this a wild cat or is your chamber that out of spec ?

What measurements were you trying for when you molded you chamber ?

6x45 or 6mmAR is a necked up .223. I got a set of dies with the gun (Lee IIRC but could have been the first set of Redding) and I was only getting 5 or so loadings out of brass before I had issues. I did not care about the case mouth splits, but the case separations were a PITA. So I read up, consulted some pretty smart people, changed brass to all Remington brass, (just for consistency, not because its awesome brass) annealed more, and reduced my neck bump. I was full length sizing since this is an AR. Almost everyone I consulted told me that I was just going to have to watch my brass close and live with the potential for case separation.
Then I was talking to a pretty smart feller one day and he pointed out that the dies I had were specifically built for a bolt gun, and my AR chamber might be a touch looser which was causing the brass to be worked pretty hard everytime I sized it. SO I cast the chamber, sent the casting, my existing sizing die, and some spent casings to Redding and they made me a shiny new die specific to my gun. Well, as specific as it needed to be. I believe you could use my dies to load for any BHW 6x45 chamber and be fine.
Pretty much instantly I started getting 8 to 12 loadings per case, and thats with the Remington brass. Have not had a case separation in the two years since.

[LynnJr]

Is that because they expand more do to less material to stretch ? My thought was when using commercial chambers .They often have a generous diameter in the neck area . The thinner walled case necks have further to expand and may be less likely to seal as well .



I don't disagree for the most part . My point was if the firearm is hand held . Your variation in hold will likely have a larger effect on velocity then if you FL sized or not .

Also if you FL size aren't you reducing case volume therefore increasing start pressure ?? Shouldn't a neck only sized case have more case volume . So the same 43gr charge would have less start pressure then a case with less volume ?

What if you have a jump to the lands . Doesn't all that start pressure go out the window do to gas escaping around the bullet likely allowing soot to get further down the neck before peak pressure ?

MetalGod
If you have two pieces of steel that will handle the same amount of pressure then make one of them half the thickness the thinner one will conform to the chamber easier than the thicker one.

On the full length sized brass picture a balloon in a glass jar.
Neck sized brass would represent a fully inflated balloon and full length sized brass would resemble and empty balloon.
If you put powder in the empty balloon it would eat up your pressure filling the balloon.

OP
Since the gun in question is a break open action try something very pointy underneath the brass the collapse it.
I would not try a screwdriver as that has the potential to scratch the chamber.
Something like an Awl would work. Tap it in then move it over very slightly and repeat. Brass isn't that tough so once you get it away from the chamber wall it should pop out.

[Metal God]

I want to start this post by saying I've only been questioning if you can notice a velocity change from a neck sized case to a FL sized case when fired from a rifle . Said rifle is not in any kind of rest and does not weigh 25lbs . I'm talking standard 8 to 12lb rifle on front and rear bag or prone with a Harris type bipod .

If you put powder in the empty balloon it would eat up your pressure filling the balloon.

Although I understand what you are saying . It's just not going to change your velocity much . Diffidently no more then inconsistent hold .

Are you saying if you have a FL sized cartridge and that cartridge produces MAX pressure . If I only neck size I can put another .5gr to 1gr of powder in the charge because the case volume is more?
Or are saying the opposite . If a neck sized load is at max pressure you can up the charge if you FL size the case because the case expanding eats up some of that pressure ?

I'd need to look at my note but I recall using IMR 4064 and 178gr A-max in a 308 . every .5gr of powder upped the velocity about 35 to 45 fps . I've done tests that show rifle hold can effect your velocity that much .

So what are we talking about here then ? Your theory would seem to indicate if FL sizing effects/reduces velocity 40fps . you should be able to adjust charge to get that velocity back yes ? If you're reducing velocity , you must be reducing pressure . If FL sizing does not effect velocity by 40fps . Then your rifle hold would be more important then if you FL size or not Y/N

I'm not arguing or trying to be snarky . These are real questions I'd like your opinion on . I completely understand your point of the balloon in a glass . I'd like you to show the test results you have and the data you got when testing the difference from neck only and FL sized cases . How much velocity variance did you get , what type of rifle and how/what was used to fire the rifle .

I'll dig my notes out on my rifle hold test and post if you post your test data Neck sizing vs FL sizing .

[LynnJr]

MetalGod
Picture a standard cartridge put into an Ackley Improved chamber. You won't get top velocity because you are taking away the peak pressure expanding the case.

The change is very small and would get lost in the extreme spread for most reloaders.

[McGuiver]

Case head separation...223 caliber...

I just culled thru 200 more pieces of brass to get ready to reload. I found 18 that needed to be pulled.

Breakdown of rounds below. All have 12 firings.

14 cases with WMA 15 head stamp. NATO rounds.

1 case with WCC 82 head stamp. NATO round.

2 cases FC 223 Rem head stamp.

1 case Lake City 10 head stamp. NATO round.

It seems to be about 10 percent of my brass so far. Time will tell.

I'm just shooting middle of the load round for 55gr FMJ rounds. The only time I have pushed to the max is with 40gr Ballistic Tip Nosler Bullets. They like to go fast, and are very accurate with my single shot rifle. (3800 FPS fast). They sound like a heavier bullet when they hit steel at 200 yards. They also cause more damage to the steel (AR500 plate) then 55gr FMJ (3000 FPS) rounds at the same distance.

Here are the worst ones for a pic.




Sent from my iPad using Tapatalk

[Metal God]

Thanks Lynn i was thinking the same thing . This has peaked my interest though and i think i'll run some test of my own to see what redults i get .

[fguffey]

Here are the worst ones for a pic.

The picture you posted has nothing to do with case head separation. When my cases are fired I can tell how much of the case was supported by the change in color between the case body and case head.

And then there is case head expansion.

F. Guffey

[McGuiver]

The picture you posted has nothing to do with case head separation. When my cases are fired I can tell how much of the case was supported by the change in color between the case body and case head.



And then there is case head expansion.



F. Guffey

On these you can feel the line on the inside. That is where the other case separated. At 12 firings, I think I maybe good. Better to be safe then hurt. The picture is not the best, but there is a noticeable ring on the outside as well.


Sent from my iPad using Tapatalk

[fguffey]

but there is a noticeable ring on the outside as well.

I will bet there is but if there is I will promise the line on the outside will be shiny. that is the way it is when brass stretched between the case head and case body.

F. Guffey