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Old October 8, 2012, 07:37 PM   #1
danny42984
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? on resizing .223

I am getting ready to adjust my sizing die to do some decapping /resizing. I am gonna use a Rock Chucker single stage press for this and I have an RCBS FL die set (11101). I have measured cartrige head space(fired cartriges from the AR I am loading for) with a Hornady Cartridge headspace gauge. The fired cartridges measure 1.4575 . I assume I want to set up the die to push the neck back .002 to .003 (this is what I read in the manuals). So this would be 1.4545? The reason I ask is that a new round measures 1.4505 in my cartridge headspace gauge. Would it be better to push the shoulder back to what a new cartrige is or just push it back a few thousands from what a fired cartridge measures? I will only use the ammo I reload in the one AR. I hope this is not too confusing. Im just getting started reloading and I'm taking baby steps
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Old October 8, 2012, 07:54 PM   #2
Creeper
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Quote:
The fired cartridges measure 1.4575 . I assume I want to set up the die to push the neck back .002 to .003 (this is what I read in the manuals). So this would be 1.4545?
I assume you mean you want to bump the shoulder back, not the "neck"... and yes, your math is correct. But...

There are lots of variables here. The fact that it's a AR... the chamber, the dies, lube, you and your abilities, condition and quality of the brass etc etc.
The problem is that if you bump the shoulder back, from a fired case dimension, only .002"~.003" it still might be overly snug in the case body diameter.
To be on the safe side, I'll say that if you want to avoid working the brass any more than necessary, you start by going up a few thousands from your unfired (1.4505") ammo... if that cycles reliably, then add a few more thousands from there. Once you see signs of cycling issues, back down .002" and call it good.

In other words, go up from minimum rather than down from max.

Cheers,
C
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Old October 8, 2012, 08:03 PM   #3
Nathan
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First, the ammo you measured is sized for a 223 rem chamber. Your rifle is a 5.56 chamber, it seems. In general, 0.002 - 0.003 is good. In bolt guns, I shoot for 0 to -0.002. In my AR, I like to see 0.002 - 0.005 in an FL die.

So, you are in the ballpark, IME, but don't forget that there is quite a bit of variation in FL sizing. Most of your variation is controlled by consistency of lubrication. Get inside the neck too. I often measure the first 10 and then like 1 in 25 to be sure I'm being consistent enough.
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Old October 8, 2012, 08:49 PM   #4
danny42984
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Thanks for the replys. Good info..just what I was looking for. As for lubing inside the neck what is the best proccess for this? rubbing a small amount in there with a pipe cleaner or just spraying it good?..other?. I know i dont want so much that the powder will stick to it. I have RCBS case lube-2 (kinda thick n sticky) and I have Hornady one shot case lube. Thanks again for the advice!
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Old October 8, 2012, 08:56 PM   #5
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It is very easy to determine if you have moved the shoulder back for your AR. After you size a few and get your die adjusted for the shoulder setback you want:

- wipe off the case lube from a sized case
- move the takedown pin to allow the upper to rotate open on your AR
- slide the BCG back
- slide the sized cartridge into the chamber
- the bolt should slide forward and lock with light to medium finger pressure on the back of the BCG

If it passes this test, it will chamber just fine during normal firing.
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Old October 8, 2012, 10:41 PM   #6
Nathan
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I use a que tip in the necks. I tumble after case work to get the lube off.
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Old October 8, 2012, 11:35 PM   #7
the led farmer
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Get some decent calipers if you don't already have them and use those to take measurements, I wouldn't rely on a headspace gauge alone for accuracy down to thousandths of inches.
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Old October 9, 2012, 05:10 AM   #8
danny42984
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in reply to Led farmer- yes the gauge that I have mounts in a caliper so that the headspace can be measured with it.
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Old October 9, 2012, 06:49 AM   #9
steve4102
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All good advice above.

Don't forget this very important step before you size them all and load em up.

Quote:
It is very easy to determine if you have moved the shoulder back for your AR. After you size a few and get your die adjusted for the shoulder setback you want:

- wipe off the case lube from a sized case
- move the takedown pin to allow the upper to rotate open on your AR
- slide the BCG back
- slide the sized cartridge into the chamber
- the bolt should slide forward and lock with light to medium finger pressure on the back of the BCG

If it passes this test, it will chamber just fine during normal firing.
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Old October 9, 2012, 07:29 AM   #10
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Danny,
You really don't need to worry about those measurements. Just follow the RCBS instruction sheet for setting up the sizing die and you're good. After sizing, check length, and if over 1.760" trim back to 1.750", chamfer and deburr. Otherwise leave alone.

One shot works great. Take 50 or so cases in a bowl or tupperware style container. Spray well. Shake, spray again. Enough gets in the necks to avoid sticking in the die. I squirt a shot up into the die to when I think of it. There's nothing magic about case lubing. If the case goes in and out of the sizing die without hanging up, relatively smoothly, it's good. Wipe the cases after sizing with an old undershirt.
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Old October 9, 2012, 08:45 AM   #11
Bart B.
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Regarding lubing any inside part of the case, that lube needs to be removed before putting powder in the case. Otherwise, that lube will contaminate the powder it touches and change its burning characteristics. And different amounts of lube in the case mouth changes the bullet's release force needed increasing muzzle velocity and peak pressure spread. This increases vertical shot stringing on the target.

As for setting up one's die in the press, fired case shoulders need be set back enough so the bolt closes on them with zero force; no binding whatsoever. Otherwise, when the bolt binds (even the slightest amount) on the case head, it won't seat in battery exactly the same for each shot. And that degrades accuracy. If accuracy's not important, then go ahead and let the bolt bind any amount you want on your loaded rounds. Note the ejector pushes the loaded round forward perfectly centering its shoulder in the chamber shoulder where it stops even with several thousandths case head clearance to the bolt face.

Yes, set fired case shoulder back 2 to 3 thousandths; you'll get better accuracy and case life.

Last edited by Bart B.; October 9, 2012 at 11:38 AM.
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Old October 9, 2012, 03:17 PM   #12
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Quote:
Danny,
You really don't need to worry about those measurements. Just follow the RCBS instruction sheet for setting up the sizing die and you're good. After sizing, check length, and if over 1.760" trim back to 1.750", chamfer and deburr. Otherwise leave alone.
I was under ther impression that all once fired cases had to be trimmed to 1.750, is this correct or not ? If you don't trim and have cases of various length, what does that do to the accuracy ?
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Old October 9, 2012, 03:26 PM   #13
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I don't bother trimming until it measures past 1.755 just to make sure it has room to expand but since its semi it shouldn't be an issue. Dont make more work for yourself than is necessary. Trust me it gets old after a while, be safe... yes, but over diligence can burn you out too.

As far as accuracy, having different cases lengths isnt going to be a bother to accuracy as long as your are measuring per O-give anyway. Yes you'll have to adjust a bit on the seater die but that's necessary anyway if your working for accuracy.
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Old October 9, 2012, 03:37 PM   #14
moxie
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Oneshot does not contaminate powder or primers. Don't worry about that. Yet another reason to use Oneshot. I've used it for quite a while and the rounds always go bang.

The 1.760" measurement for max case length is the standard found in all handbooks. When cases exceed that, you trim to 1.750". If the max length is not specified, it's usually listed as .01" longer than the "trim to" length.
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Old October 9, 2012, 03:38 PM   #15
Bart B.
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Loaded bottleneck cases headspacing on their shoulder with the same head-to-ogive dimension will still have different amounts of bullet jump to the lands. That's 'cause the head-to-shoulder distance varies a few thousandths. Whatever that variance is will be the varience of bullet jump to the lands.

But as long as it's only a few thousandths, accuracy should not suffer.
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Old October 9, 2012, 06:01 PM   #16
danny42984
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Quote:
It is very easy to determine if you have moved the shoulder back for your AR. After you size a few and get your die adjusted for the shoulder setback you want:

- wipe off the case lube from a sized case
- move the takedown pin to allow the upper to rotate open on your AR
- slide the BCG back
- slide the sized cartridge into the chamber
- the bolt should slide forward and lock with light to medium finger pressure on the back of the BCG

If it passes this test, it will chamber just fine during normal firing.
When using this method I found that I have to use a lot of finger pressure to chamber any of my resized rounds and even new rounds. What does this tell you? I can feel the way it should feel when I close the bolt with no round in the chamber. What should I do to find out why it is "stiffer" than it should be? Btw, I have not had any malfunctions occur at all with new ammo and have not fired any reloads yet.
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Old October 9, 2012, 06:44 PM   #17
steve4102
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Quote:
I was under ther impression that all once fired cases had to be trimmed to 1.750, is this correct or not ?
No this is not correct.

223/5.56 brass has a trim to length of 1.750 and a max length of 1.760. Anything in between is fine as far as proper fit goes. For ultimate accuracy all cases should be trimmed to the same length whatever that may be, as long as it's between 1.750-1.760.
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Old October 12, 2012, 01:05 AM   #18
tom234
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I just read the SAAMI .223 Remington length was changed to 1.760-.030 in 2001. One can thus trim to 1.730.
http://www.saami.org/pubresources/cc...0Remington.pdf
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