lose primer pockets, why?

Rich Coyle

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Without your velocities, that info isn't very helpful; however...
Load data by grains, is not a gospel; merely a reference. The velocity associated with the grains is what tells you where your powder lines-up burning rate wise, compared to tested data.
I would hazzard that you are over-pressure.

I agree with this poster as far as over-pressure WITH THIS BRASS.
 

dwm

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The rim on the .303 holds the case up against the bolt, dah ...

Same for belted mags.
 

dwm

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I was commenting on bigedp51 post about the rimmed .303 cartridge and the huge headspace he was mentioning.

The belt on belted magnums is there for the same reason, to keep cartridges with excessive headspace up close to the boltface.

I agree that most reloaders headspace belted magnums off the shoulder, not the belt.

I have had headspace issues with WSM cases cause excessive pressure.

The headspace difference between full length sized cases with hard brass vs freshly annealed cases was causing me problems.
 

bigedp51

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The rim on the .303 holds the case up against the bolt, dah ...

Same for belted mags.

At the maximum military headspace of .074 and a rim thickness of .058 you have .016 between the rear of the case and the bolt face. Texas may have wide open spaces "but" head clearance is what causes the brass to stretch.

It doesn't matter if the case has a rim, a belt or headspaces on its shoulder, it is the "air space" between the rear of the case and the bolt face and the case stretching to meet the bolt face that causes case head separations. dah ...

headspacestretch-c_zps8f362fcb.gif


HeadClearance_zpsf30a3af1.gif


HEADCLEARANCE-a_zps1a9a1011.jpg


And even Lone Star and Pearl beer can have too much headspace. dah ...

excessheadspace_zpsf2634b56.jpg


Signed
bigedp51
1968 graduate of Flour Bluff High School, Corpus Christi Texas. dah ...

How do you bury a six foot Texan?

You beat the crap out of him and put him in a match box. dah ...
 

dwm

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LOL, great post! I love it.

I think we are saying the same thing.

Sorry for the "dah", didn't mean to start something.

In addition to causing the case to stretch, too much headspace can cause excessive pressure and hence expansion of the case head and primer pocket.
 

bigedp51

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How does too much headspace cause a increase in chamber pressure? This is why I posted the Enfield section above and headspace settings

Excessive headspace would leave more of the base of the case unsupported. But I do not see how or why it would cause higher chamber pressure.

Brass stretches when you exceed its elastic limits/strength, and not all cartridge cases are made the same.

Below is a Lake City 5.56 case, it has harder brass and a thicker flash hole web which adds radial strength to the base of the case. This is because military firearms have longer headspace settings and larger diameter chambers.

webthickness_zps81482a55.jpg


So again, how does a increase in headspace cause a increase chamber pressure?
 

MagnumManiac

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LOL, great post! I love it.

I think we are saying the same thing.

Sorry for the "dah", didn't mean to start something.

In addition to causing the case to stretch, too much headspace can cause excessive pressure and hence expansion of the case head and primer pocket.

This statement is completely false!
Headspace has NO bearing on pressure, if it is excessive, it is more likely to REDUCE pressure due to the extra space of expansion.
There is ONE, and only ONE cause of head separation, and that is excessive headspace, either caused by the chamber, or the handloader pushing the shoulder back too far.
No head separation I have ever seen showed signs of excessive pressure, primer pockets were still tight. Some cases had body dents, but that is to be expected when the gas is OUTSIDE the case.

Cheers.
lightbulb
 

10X

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I can not afford $1 per case so what's the best alternative? What would be the best mil brass to use?
Thanks
 

bigedp51

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Winchester .243 or 7mm-08 brass is the hardest of the American made brass and half the cost of Lapua.

At the link below .243 brass was used for forming the 260 Ackley, but because of problems he went to .260 Remington brass to save work.

260 Ackley Case Forming


The link below is for Lake City long range brass used in sniper rifles and better quality than standard LC 7.62 brass.

.308/7.62 - LC Long Range - Cleaned - 100 Pieces


If you use 7.62 Lake City brass you will have thicker necks and the same problems with donuts as the first link above.

I bought 100 standard 7.62 cases to form into .243 cases but I had problems with neck thickness uniformity and stopped after making 10 cases.
 

slickshot223

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Winchester .243 or 7mm-08 brass is the hardest of the American made brass and half the cost of Lapua.

At the link below .243 brass was used for forming the 260 Ackley, but because of problems he went to .260 Remington brass to save work.

260 Ackley Case Forming


The link below is for Lake City long range brass used in sniper rifles and better quality than standard LC 7.62 brass.

.308/7.62 - LC Long Range - Cleaned - 100 Pieces


If you use 7.62 Lake City brass you will have thicker necks and the same problems with donuts as the first link above.

I bought 100 standard 7.62 cases to form into .243 cases but I had problems with neck thickness uniformity and stopped after making 10 cases.

If this was mentioned in earlier posts, I missed it:: Your necks may be to thick which will have a direct effect on pressure, neck turning may be required!!
 

bigedp51

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If this was mentioned in earlier posts, I missed it:: Your necks may be to thick which will have a direct effect on pressure, neck turning may be required!!

Reducing the neck diameter from .308 to .243 "increased" the neck thickness variations. And some of the converted 7.62 LC cases ended up with .008 or more neck thickness variations. And as shown below turning the neck does not center the bullet with the case.

neckcenter_zps94286f86.jpg


Using standard LC brass means a lot of sorting through cases looking for more uniform cases that are worth turning. But the link I posted also shows that when neck turning donuts become a problem. There is a reason why competitive shooters spend $1.00 per case for Lapua brass and do nothing to it.

Below is a Remington .223 case showing .004 neck thickness variation and this was the average with some at .001 and others at .008 variation.

IMG_2136_zps079ece9b.jpg


IMG_2137_zps66bcfc13.jpg


I have a five gallon bucket of this Remington brass and it is not worth neck turning and I just use it as blasting practice ammo in my AR15 carbine.

Bottom line, you can't make a silk purse from a sows ear.
 

10X

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here are my necks. 3 pictures are: a fired case, loaded case and neck thickness of brass after sizing it down (7-08 to 260)
 

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bigedp51

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You can not accurately measure neck thickness variations with vernier calipers.

Below with one 360 degree spin of my case any thickness variations are immediately seen on my gauge. The first thing I do when sorting and prepping cases is check the case with this gauge below. And any case with excessive neck thickness variations are rejected outright. And these case are used as blasting ammo or fouling shots.

IMG_2137_zps66bcfc13.jpg
 
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