A tale of two cases

mofosheee

mofosheee

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Somewhere in Colorado
Hello the High Road

Rookie alert. Still confused about shoulder bump. I want to start shooting range brass (.223/5.56) out of my AR. God only knows where it came from. Since each piece measurres different and is not from my gun, I don't see how shoulder measurements relevant? In this circumstance, it is typical for reloaders to advance with FL resizing and on the condition that the cases pass a gage check good to load? Or am I off base here ?
Never encountered it...........is the condition of a shoulder bumped back too far indicated by a case sitting too deep in a case gauge rendering it trash?

On the other hand, if I collect once fired brass from my gun a consistent shoulder set back of say, 0.004" can be obtained provided my dies were set up properly? Do people measure shoulder length before and after firing rounds?

Thanks again!
 
FL resize. Check with a case gauge or whatever method you prefer. Cases that don’t pass the gauge get sized again with the die turned in a little more. Gauge them again.

Whether from your gun or another gun, you still have to FL size and gauge after each firing, for a semi auto rifle. Trim if needed.
 
Option # 1:
Size to fit a Wilson or Sheridan case gauge for .223 and you won't have any issues.

Option # 2:
Take fired cases from your rifle, move the shoulders back .002/.003 and you won't have any problems.

Yes, I measure 6 Dasher cases after they are fired and after I size them to make sure my die is set up where I like it.

It's not overly complicated. Pick option # 1 or option # 2 and be happy.

I suggest a case gauge, it's simply easier/more foolproof.
Wilson .223 Case Gauge Pic 3.JPG Wilson .223 Case Gauge Pic 5.JPG Wilson .223 Case Gauge Pic 6.JPG
 
Walkalong said:
Option # 1:
Size to fit a Wilson or Sheridan case gauge for .223 and you won't have any issues.

Option # 2:
Take fired cases from your rifle, move the shoulders back .002/.003 and you won't have any problems.

Yes, I measure 6 Dasher cases after they are fired and after I size them to make sure my die is set up where I like it.

It's not overly complicated. Pick option # 1 or option # 2 and be happy.

I suggest a case gauge, it's simply easier/more foolproof.
View attachment 1190552View attachment 1190553View attachment 1190554
Click to expand...
Yup....have the Wilson gauge. I usually make everything more complicated than it should be. Thanks
 
As walkalong says a good case gauge takes all the mystery out. If my first reloads fail to chamber the case gauge will let you know if it's my rifle's chamber or my reloads. Sometimes reloads for semi-autos (like my M1A) require a small base die. I have even had unfired factory ammo fail to chamber and fail the case gauge. It hasn't happened very many times but it has happened.
 
In ther old days we called it ( the cutesy term "shoulder bump") Partial Resizing ... because you didn't full length resize the case , you just pushed the shoulder back enough so it would chamber in your rifle ...
But ... this only works with a case that has been fired in your rifle !For range picked up brass and mixed once fired brass ... you Must Full Length Resize them and check to see if they will chamber and extract easily in your rifle's chamber ... and don't check them in some "Gauge" just because they fit some gauge it don't mean they will fit in your rifle's chamber ... Trust Me On This One !!!
Some still wont chamber even after you full length re-size them .
So save the shoulder bumping for later ... after you have the brass chambering in your rifle and after you have fired the brass in your rifle's chamber .
Gary
 
Either way partial sizing or neck sizing is not appropriate for a semi auto with a floating firing pin IMO. For a bolt gun or even a lever gun, sure. For semi autos you accept a little shorter brass life (possibly) for safe/reliable chambering.
 
Walkalong said:
You do indeed size the body doing that. It's "partial" full length sizing, assuming the die isn't hard against the shell plate or holder.
Click to expand...
Exactly. But to the OP, note that with standard dies, if you’re lowering the die enough to bump the shoulder back correctly, you’re FL sizing anyway. If the die isn’t touching the shell holder or plate, the shoulder of the die isn’t contacting the brass… unless you’ve milled some material off the bottom of the die. You have to go out of your way NOT to FL size using standard dies.
 
1KPerDay said:
But to the OP, note that with standard dies, if you’re lowering the die enough to bump the shoulder back correctly, you’re FL sizing anyway.
Click to expand...
Of course.
1KPerDay said:
If the die isn’t touching the shell holder or plate, the shoulder of the die isn’t contacting the brass
Click to expand...
Not necessarily correct, most times it is unless you are a good bit off the shell holder or plate.

That said, if the die is too high, correct, it isn't touching the shoulder yet.

The case shoulder is actually pushed forward before it is pushed back, because
the case body is squeezed in before the die shoulder contacts the case shoulder.
 
frogfurr said:
Walkalong said:
Of course.

Not necessarily correct, most times it is unless you are a good bit off the shell holder or plate.

That said, if the die is too high, correct, it isn't touching the shoulder yet.

The case shoulder is actually pushed forward before it is pushed back, because
the case body is squeezed in before the die shoulder contacts the case shoulder.
Click to expand...
Click to expand...
The explanations of what occurs to brass during resizing were helpful. Thanks
 
Last edited:
mofosheee said:
In this circumstance, it is typical for reloaders to advance with FL resizing and on the condition that the cases pass a gage check good to load? Or am I off base here ?
Never encountered it...........is the condition of a shoulder bumped back too far indicated by a case sitting too deep in a case gauge rendering it trash?

On the other hand, if I collect once fired brass from my gun a consistent shoulder set back of say, 0.004" can be obtained provided my dies were set up properly? Do people measure shoulder length before and after firing rounds?
Click to expand...

All firearms are different, no matter how slight. So if you load ammunition perfectly for one, it might not even fit in another. Tolerances in allowed dimentions (+/- .00xx) allow this to occur.

So I can set a die up for a given rifle and the case might not pass a case gauge (or fit in other rifles, tighter in the tolerance range) but it might even shoot better, more than likely have longer case life and require less trimming.

www.youtube.com

Setting size die for AR type rifle.

www.youtube.com www.youtube.com

I suggest measuring before and after firing as well as before and after sizing, to fully grasp whats going on.
 
jmorris said:
suggest measuring before and after firing as well as before and after sizing, to fully grasp whats going on.
Click to expand...
Yesterday, I did exactly as you recommended in my JP Wylde barrel. New/never fired rounds measured 1.448" mean case head to shoulder before firing. 1.460" (ish) after firing.
I know every chamber is different. Is that typical "growth" for before and after firing? Learn a lot from a piece of brass.
 
If fired in a simi-auto no. The round is extracted under pressure stretching the case. Yours is excessive, which means you may be over gassed, bolt unlocking too soon.

If you have a way to turn off the gas so it does not unlock, do so and try again.
 
Blue68f100 said:
If fired in a simi-auto no. The round is extracted under pressure stretching the case. Yours is excessive, which means you may be over gassed, bolt unlocking too soon.

If you have a way to turn off the gas so it does not unlock, do so and try again.
Click to expand...
Yes, fired in semi auto and yes, I have an adjustable gas block. Easy enough, I'll step it down.
0.012" raised my eyebrows. Thanks for the advice!
 
Brass is ejecting approx @ 3:00 with no damage to cases. I'll step down the gas per mfg instruction and re examine cases. And I would suppose this brass is trash. Thanks again
 
Last edited:
mofosheee said:
Brass is ejecting approx @ 3:00 with no damage to cases. I'll step down the gas per mfg instruction and re examine cases. And I would suppose this brass is trash. Thanks again
Click to expand...
You may get 1-2 reloads before the case head separations. I would do a good case inspection prior to reloading them. Carry a cleaning brush with you encase this happens. All you need to remove it head is just push the brush into the neck then pull back. The bristles will grab the neck and extract the piece.
 
Walkalong said:
As it should
Click to expand...
Confirmed head space with "go no go" gauges. Went to the range to "recalibrate" the JP gas block per mfg's instructions. Measured 20 (ea) case shoulders of Federal 62gr M855's.
1.455" mean before firing, 1.459" mean after. I see no problem here. So the question is,

In post #15, I recorded shoulder lengths of 1.448" before firing. Is this much varience in length typcial between manufactures?
 
Am guilty of collecting 223 brass from the range in quantity, and using it. From experience, ended up buying a small base die and full length sizing to minimum for the first cycle. Then attempting to segregate by maker. Doing this, the shoulder datum will not be as consistent as just resizing brass from your own rifle. After the first resizing/firing cycle, the shoulder datum gets much more consistent and shouldn't need a sb die.
 
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