New brass then after first shot

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misskimo

New member
Hey. Been reloading for about 6 months. Been having a blast. I bought the lees 50th Anv kit for for my collection of rifles. 223, SKS, 22-250, 243, 270, 30-30 , 308, 30-06 , 338 win mag and 300 ultra mag , winter is here so I can't shoot to test out my test loads. But my question is. New brass for each of my cal will run low and then I will have to reload used brass. You see. I did all these load groups to find what works best with my gun, with new brass, After the new is gone , I will have too find the magic load again huh?
Tonight I loaded the last of my new 308 brass , test loads with a different bullet . So for kicks and giggles, I dug in my box of shot shot once brass and grabbed a 308 shell. Filled it slapped full of powder. Then filled up a new brass to the top packing it good. Measured the shell and powder and man. 1 gr difference, I bet my pet load with new brass will fly out the end of the barrel with used brass huh?
What do y'all do



Tony
 
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roklok

New member
That is a very unscientific method of measuring capacity, and I can not imagine ten grains of powder capacity difference between new brass and once fired brass (unless it was fireformed brass in an improved chamber, and even then 10 grains is a stretch). A better aproach is to weigh the amount of water each case can hold.

That being said, I normally do not use brand new brass for serious purposes, reserving it for range use and practice. I work up pet loads and hunt with brass that has been fired at least once.
 
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hogcowboy

New member
I don't see what the big deal is. I've never seen that much difference between new brass and once fired unless you are look for serious long range shooting. Put your pet load in both. Just use the new stuff for target shooting.
 
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Myke_Hart

New member
Are you sure you did not compare a 30-06 case to your new 308 cases?
Doing that should give you somewhere around a 10 grain difference.

Then again if you did not subtract the weight of the brass it might be possible to be that far off.

Your measurements will also be skewed if one peice of brass was fired out of your gun and the other out of someone elses. The same thing happens if one peice is unfired and the other is fired. If this is the case...Full length size the new and old brass being careful to keep the spent primer. Then put an old spent primer back in the cases. (this will hold the water in)

Weigh the clean and empty cases...new brass and old brass... Write that down.

Fill them both with water and tap out the bubbles and make sure they are full.

Weigh them full of water...write that down.

Subtract the empty weight from the full weight. (the result is your case capacity)

There should not be a huge difference between the capacity of the old and new peices of brass if they are both commercial 308.:)

Nato 308/7.62x51 will give you a different capacity than commercial as well.
 
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Unclenick

Staff
misskimo said:
After the new is gone , I will have too find the magic load again huh?
Click to expand...

Not at all. Here's the thing:

Pressure depends on how much volume the powder is burning in. In loads that fire at approximately 30,000 psi and up, the case expands until it sticks to the chamber wall and the head stretches back and touches the breech face all before the powder has got very far in its burning curve and before the bullet bullet has moved very far down the bore. The result is that the peak pressure depends on the volume the case expands to in the chamber, not on the volume the case has when it is inserted into the chamber. So, the chamber size is what is determining peak pressure and barrel time, not the volume of the new or resized cases.
 
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4runnerman

New member
"After the new is gone , I will have too find the magic load again huh?"

No. Deprime,resize,load and go TaDa,all done.. Check case length if your serious:D
 
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mehavey

New member
I dug in my box of shot shot-once brass and grabbed a 308 shell. Filled it slapped full of powder. Then filled up a new brass [case] to the top packing it good... 10 gr difference.
Click to expand...
I too, have a [real] problem envisioning a 10 grain diffference between two cases of the same 308 Win cartridge.

Please repeat this comparison using water (full case -minus- empty case) and tell us the difference in net water weights. Also tell us the brass manufacturer(s).
 
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medalguy

New member
10 GRAINS???? No way. I only put about 42 grains in 308 when loading and the powder is near the top of the case. No way could I ever get another 10 grains in there, not that I would want to.:eek::eek::eek:

I bet my pet load with new brass will fly out the end of the barrel with used brass huh?

You're not serious, are you? If so let me know which range you are planning on using. I'll stay away.
 
4

4runnerman

New member
yes a error was made for sure here somewhere.The only way this could happen is if case length grew that much,which in that case would not matter because it would not fit in you gun any more:D 10 gns is a lot ogf powder
 
7

700cdl

New member
Variables with brass

Are you weighing one with a spent primer and the other with a new primer?
Is the once fired brass tumbled?
Is the once fired brass trimmed, reamed, and chamfered?
Are they both the same headstamp and from the same lot?
Once fired brass will often have a different volmetric size as it has been spread out in areas where it was once thicker and expanded to your guns chamber. Also, residue will adhear to the inside changing its volmetric size as well. There are a lot of possible variables between new and fired brass.
 
7

700cdl

New member
Variables with brass

Even if you FL size and trim it, it will still have different demensions than new brass. Once it has been fired it will stretch and thin out changing shoulder position as well.
 
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temmi

New member
You Must check case length as a safety measure.

""After the new is gone , I will have too find the magic load again huh?"

No. Deprime,resize,load and go TaDa,all done.. Check case length if your serious"



You Must check case length as a safety measure.

If the case is too long the neck can crimp the bullet and raise the pressure.

Do not exceed the maximum case length
 
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wncchester

New member
"After the new is gone , I will have too find the magic load again huh?"

But the question is about the need for further load development. :confused:
 
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misskimo

New member
Well yeh. And I recon I will load the used brass with my new brass loads and see. I just prep and resized about 60.
Also. My bad on the 10 g. Take away the 0. 1 g bigger after a shot. I would have thought they do get a tad bigger after its first shot is all which would mess with you pet load when new. My bad. Yall
 
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Cowboy_mo

New member
Look @ the OP..... he said a 1 (one) gr diff.....

Misskmo..... you stated a 1 gr difference in your OP. I been going nuts wondering where this 10 (ten) gr difference came from.

Unless you are loading max or max plus (very dangerous) once fired cases and new cases should hold the same loads w/o problems. At least that has been my experience in the short time I have been reloading.
 
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