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Neck tension problem 6mm CM using FL resizer.

springer01

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Minuteman
Dec 27, 2005
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Brownfield, Texas
I am FL resizing some once fired (in my rifle) Hornady 6mm Creedmoor brass and having inconstant neck tensions. Factory loaded round Hornady Match 108 ELD-M measures .271 OD fired measures .276 OD. My reloaded round with the same bullet 108 ELD-M measures the same .272 OD, cleaned, trimmed lubed and then FL sized with a Mighty Armory FL resizer. Here is the problem some of my bullets I can slide in the neck by hand and some are tight and have to be seated with Forester Comp. seater, but both measure the same OD neck, The Mighty Armory FL resizer doesn't allow (that I can figure out) for any neck tension adjustment. I've never had neck tension issues or at least this inconsistency issues and am kind of at a loss on what to do.

Thanks
Tanner
 
I am FL resizing some once fired (in my rifle) Hornady 6mm Creedmoor brass and having inconstant neck tensions. Factory loaded round Hornady Match 108 ELD-M measures .271 OD fired measures .276 OD. My reloaded round with the same bullet 108 ELD-M measures the same .272 OD, cleaned, trimmed lubed and then FL sized with a Mighty Armory FL resizer. Here is the problem some of my bullets I can slide in the neck by hand and some are tight and have to be seated with Forester Comp. seater, but both measure the same OD neck, The Mighty Armory FL resizer doesn't allow (that I can figure out) for any neck tension adjustment. I've never had neck tension issues or at least this inconsistency issues and am kind of at a loss on what to do.

Thanks
Tanner
If it we're me, I'd measure the neck thicknesses and check for consistencies.
 
If it we're me, I'd measure the neck thicknesses and check for consistencies.
That's really the only thing in mind that it could be. I tried to measure with my digital calipers but it's not a very reliable reading, guess I'll need to invest in a micrometer. Thank you.
 
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I am FL resizing some once fired (in my rifle) Hornady 6mm Creedmoor brass and having inconstant neck tensions. Factory loaded round Hornady Match 108 ELD-M measures .271 OD fired measures .276 OD. My reloaded round with the same bullet 108 ELD-M measures the same .272 OD, cleaned, trimmed lubed and then FL sized with a Mighty Armory FL resizer. Here is the problem some of my bullets I can slide in the neck by hand and some are tight and have to be seated with Forester Comp. seater, but both measure the same OD neck, The Mighty Armory FL resizer doesn't allow (that I can figure out) for any neck tension adjustment. I've never had neck tension issues or at least this inconsistency issues and am kind of at a loss on what to do.

Thanks
Tanner

If you can slide in bullets by hand than the die is not sizing the necks enough. You don’t need a tube micrometer your tell you that.
 
I Factory loaded round Hornady Match 108 ELD-M measures .271 OD fired measures .276 OD. My reloaded round with the same bullet 108 ELD-M measures the same .272 OD,
Do you have any ideas as to why? It's obvious it isn't enough, that's the reason I made the post.
You have already answered your own question.
The die isn’t sizing it down enough.

Loaded is .271
Your sized is .272

Notice that your sized is .001 larger than it needs to be at a minimum on a loaded round?

What you are seeing is that the die is sizing it just enough so that the inconsistencies in neck thickness of crappy hornady brass are able to grab onto some bullets with a thicker necked piece but the next piece with slightly thinner neck material can’t be sized down enough.

You need a die that will size it down further than less than the bare minimum.
 
Do you have any ideas as to why? It's obvious it isn't enough, that's the reason I made the post.

Your necks are too thin for this die and inconsistent in thickness. Standard FL dies will size the necks down a lot. That way no matter what brass you use and how much material you turn off the necks you will get enough neck tension to hold the bullet. As is, your die will work with thicker brass, but for Hornady cases you’ll need another die.
 
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Depending on your purposes for the loaded rounds and if you have a ton of that brass, you need to turn those necks to get consistency. And then anneal the brass.
 
Depending on your purposes for the loaded rounds and if you have a ton of that brass, you need to turn those necks to get consistency. And then anneal the brass.
If he turns them any thinner then none of the brass will hold a bullet. That’s not the solution to the problem. He needs the opposite of turning necks.
 
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If he turns them any thinner then none of the brass will hold a bullet. That’s not the solution to the problem. He needs the opposite of turning necks.
I just used Excel instead of my brain to do the math. Thanks for the catch.
 
Your necks are too thin for this die and inconsistent in thickness. Standard FL dies will size the necks down a lot. That way no matter what brass you use and how much material you turn off the necks you will get enough neck tension to hold the bullet. As is, your die will work with thicker brass, but for Hornady cases you’ll need another die.
Thank you..makes sense!
 
I have started to remove the expander from the sizing die, sand it undersized and polish it up slick.

Replace it and resizing is smoother. Then run a seperate mandrell die step to set neck tension.

Improved groups quite a bit, any caliber. I don't even measure necks anymore, don't matter.
 
👆
If you spin the decapping assembly in a drill you can get consistent results. Go slow and measure often, you can tune the expander ball pretty easily.
 
Yes I use a drill to do that but the point is that it gets way undersized from desired end neck tension.

Basically used to straiten dings and start the neck sizing slightly. I barely feel it on the upstroke.

I don't want it pulling on the shoulder. That way brass that's thick or thin doesn't matter it doesn't get stretched.

The separate Sinclair mandrell die gives the same exact result on the Inside no matter what.
 
That’s what I do if using a mandrel die also. Not sure if the op is using a mandrel, in that case he will want to tune his neck tension with the expander ball.
 
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I get you.

I ended up with bad results tuning the expander ball.

Made a good load then changed brass, oops. Then there are the neck bushings, measuring all the time, making mistakes (me) hassles.

I change brass often in 223 and 308, also occasionally on other calibers.

So I like the ease of the mandrell, everything gets .002 under no more worrying or variables. Even the 223 ar plinkers which is what convinced me of the process.

If any load is not coming togeather or starts acting up that is one thing I don't have to check.
 
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May as well say this for the op.

1: Hornady components,
problems ? Yes, I belive that.

2: Your bullet doesn't care about the neck od.
 
I am FL resizing some once fired (in my rifle) Hornady 6mm Creedmoor brass and having inconstant neck tensions. Factory loaded round Hornady Match 108 ELD-M measures .271 OD fired measures .276 OD. My reloaded round with the same bullet 108 ELD-M measures the same .272 OD, cleaned, trimmed lubed and then FL sized with a Mighty Armory FL resizer. Here is the problem some of my bullets I can slide in the neck by hand and some are tight and have to be seated with Forester Comp. seater, but both measure the same OD neck, The Mighty Armory FL resizer doesn't allow (that I can figure out) for any neck tension adjustment. I've never had neck tension issues or at least this inconsistency issues and am kind of at a loss on what to do.

Thanks
Tanner
or you dont know how to use this Mighty Armory FL resizer,
or it just size necks too large for your brass.

but I think you know know that you have body die, not FL die. you are not smart enough to know which die you must use.

use standard FL die from any producer, or use FL bushing die, where you can set your own tension.

and forget stories about how bad is expander ball in FL die...
 
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get a Lee Collet Neck Sizing Die... squeezes the neck onto a tuned neck mandrel.... neck ID always is the same and eliminates problems associated with variances in neck wall thickness and or FL die neck dimension... collet dies are quite reasonable in cost... good luck..
 
get a Lee Collet Neck Sizing Die... squeezes the neck onto a tuned neck mandrel.... neck ID always is the same and eliminates problems associated with variances in neck wall thickness and or FL die neck dimension... collet dies are quite reasonable in cost... good luck..
Yes, I've used Lee Collets for years and is what I am currently using. I have a Wilson FL bushing die now and separate die with expander mandrel coming.
 
get a Lee Collet Neck Sizing Die... squeezes the neck onto a tuned neck mandrel.... neck ID always is the same and eliminates problems associated with variances in neck wall thickness and or FL die neck dimension... collet dies are quite reasonable in cost... good luck..
this is solution for this problem.

but he must bump his sholder anyway, so he will do additional step.