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Chills1994

My last thread on concentricity issues re: LC brass

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I kind of consider SMK's to be the Cadillac of .223 bullets.  So I was disappointed when they were printing groups like this with once fired processed Lake City brass:

 

 

20180601_185854.jpg

Edited by Chills1994

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But then I bought a 400 something dollar concentrity (or runout) gauge.

 

I figured out that there was "runout" at the case necks.

 

I bought a Redding S die (a sizing die that can be set up like 3 or 4 different ways) and a Lyman M die.

 

I also bought some factory Federal XM855 and XM193.  In my fancy schmancy gauge, I learned that even the Lake City ammo had significant runout.

 

I set up a dedicated 650 toolhead with just the Redding S die and Lyman M die.  I lubed the cases and dumped them into the casefeeder's hopper.  I cranked out about 50 of those.  Then I loaded them like normal with a different dedicated toolhead that had the powder measure, the bullet seating die, and a Lee FCD.

 

 

 

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Now the groups look like this:

 

 

Screenshot_20180601-214847.jpg

 

So if you are having trouble getting your rounds to group better, it could be the (Lake City) brass you are using.

 

Buy or borrow a concentricity gauge to find out.

 

Or just buy a Redding S die and Lyman M and plan on running your processed through both dies to straighten out the necks.

Edited by Chills1994

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The biggest cause of neck runout is when the expander is locked down off center.

At the Whidden custom die website they tell you they get the most concentric cases with non-bushing full length dies.

I buy bulk once fired Lake City 5.56 and 7.62 brass and size them with a Forster benchrest die and have very little neck runout.

 

Below the Forster die has a high mounted floating expander and enters the case neck when the neck of the case is held and centered in the neck of the die. Meaning the expander can not pull the case neck off center and induce neck runout.

 

Y7Iyv8o.jpg

 

The problem with bushing dies is if the neck is reduced .004 or more in diameter when sizing it will induce neck runout. And the majority of factory chambers will allow the neck to expand far more than .004.

 

 

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On ‎6‎/‎7‎/‎2018 at 4:43 PM, Chills1994 said:

But then I bought a 400 something dollar concentrity (or runout) gauge.

 

I figured out that there was "runout" at the case necks.

 

I bought a Redding S die (a sizing die that can be set up like 3 or 4 different ways) and a Lyman M die.

 

I also bought some factory Federal XM855 and XM193.  In my fancy schmancy gauge, I learned that even the Lake City ammo had significant runout.

 

I set up a dedicated 650 toolhead with just the Redding S die and Lyman M die.  I lubed the cases and dumped them into the casefeeder's hopper.  I cranked out about 50 of those.  Then I loaded them like normal with a different dedicated toolhead that had the powder measure, the bullet seating die, and a Lee FCD.

 

 

 

 

On ‎6‎/‎9‎/‎2018 at 10:02 AM, bigedp51 said:

The biggest cause of neck runout is when the expander is locked down off center.

At the Whidden custom die website they tell you they get the most concentric cases with non-bushing full length dies.

I buy bulk once fired Lake City 5.56 and 7.62 brass and size them with a Forster benchrest die and have very little neck runout.

 

Below the Forster die has a high mounted floating expander and enters the case neck when the neck of the case is held and centered in the neck of the die. Meaning the expander can not pull the case neck off center and induce neck runout.

 

Y7Iyv8o.jpg

 

The problem with bushing dies is if the neck is reduced .004 or more in diameter when sizing it will induce neck runout. And the majority of factory chambers will allow the neck to expand far more than .004.

 

 

 

I have one of the 21st Century Shooting Concentricity gauges (IIRC $189) that works very well.

 

https://youtu.be/Dc-9gbw8Iso

 

I tried the bushing dies and never got satisfactory results even with the Lyman M die.  I'm also using the Forester and have much better results.

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Now that I think about it...

 

The 50 cases or so that I resized, I did with an RCBS X die with the center mandrel/decapping rod taken completely out.

 

I am thinking now that I haven't even used the Redding S die yet.

 

whoops!

 

 

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Even with the Forster die, I take out the expander ball and use a 21ST Century mandrel for neck expansion and a get better results

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On 6/19/2018 at 1:23 PM, fedupflyer said:

Even with the Forster die, I take out the expander ball and use a 21ST Century mandrel for neck expansion and a get better results

It's been a while, so I am trying to refresh the memory banks here.

 

I think I was using the RCBS X die to resize some of my pre-processes brass.

 

I thought I had enough lube in the cases, but about the third case in STUCK!  

 

Argghh....So in the process of getting the case out of the die, I had to predrill the primer cup/flash hole for the tap.

 

I had the die clamped in a bench vise, but once that drill bit made it through the case head, it grabbed and slammed into the X die's decapping rod/pin/mandrel assembly.  That totally boogered it up.

 

(Next time, I'll just take it to my shop with a drill press and cross slide vise.)

 

So then I was just using the X die without a mandrel/decapping rod.

 

That would have been okay, but it squished the case mouths or necks down too far.  I thought I could go tge lazy route and just seat bullets especially boat tailed bullets, but I was actually shaving off little bits of copper off the jackets.

 

So then I screwed the Lyman M die into station 2 or 3 of the same toolhead.  That made all the difference.  

 

Did I post the video already?

 

 

I will have to do some experimenting with the Redding S die.

 

I think for now...the worst case scenario...is I have about 640 rounds that need to pull the bullets off of (using a collet die in my RCBS single stage press).  And then straighten them out with the mandrel-less X die and Lyman M die.

 

I am not real keen on buying a Forstner die.  I like my system better where the mouth isn't pulled over some expander rod or ball...even if that means using a universal decapping die to knock the old primer out.

 

EDIT:  The Forster die (no "n" and just one "e") isn't all that expensive... 41 bucks and some change at MidwayUSA:

 

https://www.midwayusa.com/product/1010946147/forster-bench-rest-full-length-sizer-die

 

You talked me into it.  I'll have to get one.  

 

I figured adding "benchrest" to the name would add a 1 to the front of the price.

 

 

 

 

 

Edited by Chills1994

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Yup,the expander balls suck. I run Dillon size die with ball removed, the die is backed out so it does not fully size the case. Then a trim die, it trims and finish sizes to my liking.
On the loading toolhead it has M die, powder, MBF, seat, Lee FCD. Runout is max .003” on a MK7 650.


Sent from my iPhone using Tapatalk

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