Neck-size vs full-length-sized brass

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Neck-size vs full-length-sized brass

Post by bladeracer » 30 Jun 2018, 12:10 pm

I've been shooting a case-life test.
Ten .223 cases, 26.5gn of AR2206H, Rem 7-1/2 primer, and Hornady 55gn SP bullet.
All ten were once-fired factory PPU when I got them. Pockets uniformed to depth, and chamfered, flash holes deburred inside and out.
I collet neck-size five and FLS five.
Trimmed to 1.756" each time, mouth chamfered.

The first load was a 52gn bullet swaged from .22LR brass on 27.0gn of AR2206H, but the bullets weren't reaching the target due to the velocity. I also didn't see much value in testing with loads hotter than I normally run so I changed to the 55gn and dropped it to a 26.5gn charge.
I shot them for the third time yesterday, which was the first time I did so over the chrono.
I put fourteen reduced loads through first at 1870fps to warm the barrel.
The neck-sized ran 3244 3244 3228 3244 3205 for a mean of 3233fps, and 20mm 100m group.
The full-length-sized ran 3341 3300 3308 3367 3316 for a mean of 3326fps, and a 22mm group.
Roughly 100fps faster, or 3% increase in velocity just from FLS instead of neck-sizing.
Has anybody else measured such a difference?
I'm wondering if the idea that FLS wears the brass out faster might not actually stem from them running higher pressures due to the reduced case capacity of full-length-sized brass.

Over three loads I'm seeing about .001" growth in the neck-sized and 0.005" in the FLS'ed brass, but it seems to be reducing each time.
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Re: Neck-size vs full-length-sized brass

Post by bladeracer » 30 Jun 2018, 12:28 pm

Just for completeness, the 52gn bullet (from Tripod) on 8.0gn of Trailboss runs at 1870fps (1841fps to 1877fps), and grouped 24mm at 100m, or .8MoA. They drop 120mm directly below the high-velocity load which is very nice.
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Re: Neck-size vs full-length-sized brass

Post by No1_49er » 30 Jun 2018, 1:50 pm

Full length sizing is work hardening the brass, both when it's fired, then when you FLS.
If you want longevity from your cases, annealing would be a worthwhile additional step in your reloading procedure.
If you're only neck sizing (collet die?) you will eventually have to bump the shoulder back a smidgeon, but the brass has a much easier life.
I'm still using my original Sako 6mmPPC cases that I've been using for close on 25years.
Your observation of slightly increased velocity with FLS cases is almost certainly a result of slightly reduced case capacity and a subsequent pressure increase. Not necessarily a linear curve, but you may find that you can increase your powder charge a little to achieve the same velocity with the FLS cases, but eliminating the work hardening.
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Re: Neck-size vs full-length-sized brass

Post by marksman » 30 Jun 2018, 1:55 pm

No1_49er wrote:Full length sizing is work hardening the brass, both when it's fired, then when you FLS.
If you want longevity from your cases, annealing would be a worthwhile additional step in your reloading procedure.
If you're only neck sizing (collet die?) you will eventually have to bump the shoulder back a smidgeon, but the brass has a much easier life.
I'm still using my original Sako 6mmPPC cases that I've been using for close on 25years.
Your observation of slightly increased velocity with FLS cases is almost certainly a result of slightly reduced case capacity and a subsequent pressure increase. Not necessarily a linear curve, but you may find that you can increase your powder charge a little to achieve the same velocity with the FLS cases, but eliminating the work hardening.


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Re: Neck-size vs full-length-sized brass

Post by bladeracer » 30 Jun 2018, 3:20 pm

No1_49er wrote:Full length sizing is work hardening the brass, both when it's fired, then when you FLS.
If you want longevity from your cases, annealing would be a worthwhile additional step in your reloading procedure.
If you're only neck sizing (collet die?) you will eventually have to bump the shoulder back a smidgeon, but the brass has a much easier life.
I'm still using my original Sako 6mmPPC cases that I've been using for close on 25years.
Your observation of slightly increased velocity with FLS cases is almost certainly a result of slightly reduced case capacity and a subsequent pressure increase. Not necessarily a linear curve, but you may find that you can increase your powder charge a little to achieve the same velocity with the FLS cases, but eliminating the work hardening.


I only neck-size anyway.
I'm just doing this for my own education :-)
I don't need the brass to last longer than it does already, so annealing isn't necessary.
I get very good case life as I don't see any need to load anything near maximum loads.
Was just curious if others have seen the same velocity increase.
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Re: Neck-size vs full-length-sized brass

Post by Sergeant Hartman » 30 Jun 2018, 4:49 pm

Can you bump size with lee full length die, or do I need a different die.
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Re: Neck-size vs full-length-sized brass

Post by gunnnie » 30 Jun 2018, 5:04 pm

Get a Redding body die. Use it when the case becomes harder to chamber after collet neck sizing. It'll reduce the body back to specs without workjng the neck.
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Re: Neck-size vs full-length-sized brass

Post by SCJ429 » 30 Jun 2018, 6:21 pm

If you are comparing a collet die to a FL bushing die then I don't think you will find that the neck is worked any harder if you were to size them both two thou. If your full length die is conventional and sizes the neck 15 thou or more and then the expander button brings it back up to whatever, then this type of die will work harden the neck and lead to splitting.

Could you compare sizing one third of the neck vs most of the neck and see if there is a difference in brass life? I did this partial neck sizing using a convential die with the button removed, the brass was good for 20 reloads before I needed a body die to push the shoulder back. The brass was retired eventually because of loose primer pockets.
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Re: Neck-size vs full-length-sized brass

Post by Cooper » 30 Jun 2018, 6:24 pm

I'm still a neck sizing fan. I have being FLS my 6.5 Grendel brass recently and the FLS brass needs more trimming and appears not to be quite as accurate as the brass I have neck sized.

All the talk about full length sizing and just bumping the the shoulder doesn't make sense me. I mean it is possible. But I think to actually achieve this you basically need a custom Full Length sizing die. The dies I have Lee and Forster still size the body even if I set them to not touch the shoulder and the neck sizing fixed. I quess you could change the expander ball and Forster offer a die honing service. But that is just for the neck part and they are in the States.

Dunno. I am still learning. But that's what I think at the moment. Happy to be educated otherwise!
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Re: Neck-size vs full-length-sized brass

Post by deanp100 » 30 Jun 2018, 7:06 pm

Do you know what velocity tripods projectiles were vaporising at? I have been running some out of a 222 magnum( only fired half a dozen so far) and haven’t noticed any problems.
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Re: Neck-size vs full-length-sized brass

Post by sungazer » 30 Jun 2018, 7:25 pm

To do the comparison is hard as you have found when you FLS you are moving the shoulder 5 thou in one of my rifle using a certain die and normal shell holder it will move the shoulder 10 thou from my chamber a lot more than needed. I first started using shims from the industrial shop but have since bought a set of Redding competition shell holders which start at 10 thou greater than standard and reduce b 2 thou each down to standard. 2 thou is heaps from when they are getting tight. In that gun 8 thou will cause a potential missfire.
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Re: Neck-size vs full-length-sized brass

Post by bladeracer » 01 Jul 2018, 7:46 am

Ziad wrote:Can you bump size with lee full length die, or do I need a different die.


You can indeed, just back the die out a little.
Try to chamber the fired case.
Run it through the sizing die and try again.
If it's still tight adjust the die down a touch, try again.
When the case chambers fine, adjust the die down the tiniest bit.

A 7/8"-14tpi die will go down 71-thou with a full turn, 9-thou to an eighth of a turn - as you can see, 2-thou does not require much at all.
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Re: Neck-size vs full-length-sized brass

Post by bladeracer » 01 Jul 2018, 7:49 am

gunnnie wrote:Get a Redding body die. Use it when the case becomes harder to chamber after collet neck sizing. It'll reduce the body back to specs without workjng the neck.


The idea is not to size it back to spec. You want to keep it fire-formed, you just want to bump the shoulder one or two thou so it'll chamber.
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Re: Neck-size vs full-length-sized brass

Post by bladeracer » 01 Jul 2018, 7:53 am

SCJ429 wrote:If you are comparing a collet die to a FL bushing die then I don't think you will find that the neck is worked any harder if you were to size them both two thou. If your full length die is conventional and sizes the neck 15 thou or more and then the expander button brings it back up to whatever, then this type of die will work harden the neck and lead to splitting.

Could you compare sizing one third of the neck vs most of the neck and see if there is a difference in brass life? I did this partial neck sizing using a convential die with the button removed, the brass was good for 20 reloads before I needed a body die to push the shoulder back. The brass was retired eventually because of loose primer pockets.


Nope, not a bushing die. I have no use for bushing dies so I can't be bothered getting some just for this testing.
FLS brass does have a little more neck tension, which probably contributes something to the extra velocity.
The Lee Collet Neck Die does have an expander.
The neck-sizing with the full-length die is a good idea, I might add that to the test as well with another set of cases.
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Re: Neck-size vs full-length-sized brass

Post by bladeracer » 01 Jul 2018, 7:59 am

deanp100 wrote:Do you know what velocity tripods projectiles were vaporising at? I have been running some out of a 222 magnum( only fired half a dozen so far) and haven’t noticed any problems.


They started vanishing around 3000fps, but by 3300fps it was chronic. I'm shooting them in an 8"-twist bore though. .222Mag is probably a 12"-twist? I think we determined that keeping them below 270,000rpm was fine. Don't go above 4500fps in a 12"-twist.
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Re: Neck-size vs full-length-sized brass

Post by bladeracer » 01 Jul 2018, 8:03 am

sungazer wrote:To do the comparison is hard as you have found when you FLS you are moving the shoulder 5 thou in one of my rifle using a certain die and normal shell holder it will move the shoulder 10 thou from my chamber a lot more than needed. I first started using shims from the industrial shop but have since bought a set of Redding competition shell holders which start at 10 thou greater than standard and reduce b 2 thou each down to standard. 2 thou is heaps from when they are getting tight. In that gun 8 thou will cause a potential missfire.


Good point. I hadn't thought to check how far it is bumping the shoulder. I just do as I described above to get once-fired foreign brass to chamber in my rifle, without actually measuring it. I'll endeavour to do that next time I size them. Yep, 2-thou is all it needs to be able to chamber.
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Re: Neck-size vs full-length-sized brass

Post by Sergeant Hartman » 01 Jul 2018, 8:43 am

Thanks blade, I'll put my fls die back in the turret and see. At the moment its got a lot of lube, resized 400 once fired rounds from it. Plus got no fire formed brass
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Re: Neck-size vs full-length-sized brass

Post by SCJ429 » 01 Jul 2018, 9:29 am

Could the increase in velocity be cause by something other the case dimensions? Could you try shooting the FLS cases first and the neck sized second? This way increased fouling or temperature of the barrel would be eliminated. My feeling is that increased neck tension may cause an increase in velocity although 100 fps seems a lot
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Re: Neck-size vs full-length-sized brass

Post by bladeracer » 01 Jul 2018, 10:07 am

SCJ429 wrote:Could the increase in velocity be cause by something other the case dimensions? Could you try shooting the FLS cases first and the neck sized second? This way increased fouling or temperature of the barrel would be eliminated. My feeling is that increased neck tension may cause an increase in velocity although 100 fps seems a lot


I alternate the order with each firing to limit that effect, and shoot other ammo first so neither batch is shot in a cold bore. I hadn't been using the chrono, and only used it on Friday because I had it set up for the .30-06 anyway. I also haven't been recording group sizes as they both shoot just as well as each other. But I'll shoot the remaining loads over the chrono and record group sizes.

I decided to do this purely as an experiment to either confirm of deny the "FLS wears out your brass" view.

I should measure the neck tension as well, both for the difference, and to see if it remains constant until case failure.

I should also do this in the rear-locking No.4 Rifle as they are known for early case separation.
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Re: Neck-size vs full-length-sized brass

Post by sungazer » 02 Jul 2018, 10:00 am

bladeracer wrote:
sungazer wrote:To do the comparison is hard as you have found when you FLS you are moving the shoulder 5 thou in one of my rifle using a certain die and normal shell holder it will move the shoulder 10 thou from my chamber a lot more than needed. I first started using shims from the industrial shop but have since bought a set of Redding competition shell holders which start at 10 thou greater than standard and reduce b 2 thou each down to standard. 2 thou is heaps from when they are getting tight. In that gun 8 thou will cause a potential missfire.


Good point. I hadn't thought to check how far it is bumping the shoulder. I just do as I described above to get once-fired foreign brass to chamber in my rifle, without actually measuring it. I'll endeavour to do that next time I size them. Yep, 2-thou is all it needs to be able to chamber.


Re thinking this. I thought that 95% of shooters wouldn't adjust the dies like you explain and they would set them up as per the instructions that come with them which in nearly all cases would return the shoulder to the minimum spec. so perhaps to prove any difference and in a shorter period of time that would be the way to go.
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Re: Neck-size vs full-length-sized brass

Post by Stix » 02 Jul 2018, 3:57 pm

bladeracer wrote:I've been shooting a case-life test.
Ten .223 cases, 26.5gn of AR2206H, Rem 7-1/2 primer, and Hornady 55gn SP bullet.
All ten were once-fired factory PPU when I got them. Pockets uniformed to depth, and chamfered, flash holes deburred inside and out.
I collet neck-size five and FLS five.
Trimmed to 1.756" each time, mouth chamfered.

The first load was a 52gn bullet swaged from .22LR brass on 27.0gn of AR2206H, but the bullets weren't reaching the target due to the velocity. I also didn't see much value in testing with loads hotter than I normally run so I changed to the 55gn and dropped it to a 26.5gn charge.
I shot them for the third time yesterday, which was the first time I did so over the chrono.
I put fourteen reduced loads through first at 1870fps to warm the barrel.
The neck-sized ran 3244 3244 3228 3244 3205 for a mean of 3233fps, and 20mm 100m group.
The full-length-sized ran 3341 3300 3308 3367 3316 for a mean of 3326fps, and a 22mm group.
Roughly 100fps faster, or 3% increase in velocity just from FLS instead of neck-sizing.
Has anybody else measured such a difference?
I'm wondering if the idea that FLS wears the brass out faster might not actually stem from them running higher pressures due to the reduced case capacity of full-length-sized brass.

Over three loads I'm seeing about .001" growth in the neck-sized and 0.0045" in the FLS'ed brass, but it seems to be reducing each time.


I assumed the lower case life is from wearing out the brass from a case hardening & thinning point of view, with the difference in pressure not being a big/or the biggest contributing factor (apart from to a point governing how much stretch the case undergoes), given that each time you are FL sizing, shooting & trimming you are causing it to flow & become thinner & more brittle...?

But to answer your question re the experiment,..A load i have chrono'd with a newish rifle has given me results along the lines of what you have found with velocities, although im still puzzled by them.

Its a 22-250 & the chrono results were...
Once fired & FL sized brass (being formed) gave me an average of 3560fps,...seated for a .020" jump.
The fireformed & neck sized only brass gave me an average of (3490fps)-3500fps....seated for a .010" jump.

points of difference that may be of interest...
*the obvious of the .010" jump between the two.
*There is only .003" MAX difference in the shoulder measurement of the cases (from FLSized to formed-with the FL Sized being from the die wound ALL the way down to the shell holder), but most of the cases are only .0015"-.002" difference in the shoulder measurement from FL sized to fully formed.-other rifles i have in same chambering are atleast .0045" difference in the shoulder to head length.
*it is a very short chamber compared to the other few 22-250 chambers ive measured.
*I didnt do an actual water volume test on the cases to see the volume difference of before & after being sized/formed to get a true constant to measure from.
*Although this particular rifle has a shorter chamber & therefor load density is higher than others i have, it seems to take hotter loads--ive gone 1 full grain above ADI max & still have not hit any pressure signs that i can tell.

Im surprised to see that much difference in velocity, with such minimal differences in the loaded cartridge, but then i've never experimented in the past to know what to expect.
60-70fps less looks like a big number on paper, but i guess its not much difference in real world terms--well at least i for one would not see the difference in results on a rabbit or a fox.
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Re: Neck-size vs full-length-sized brass

Post by bladeracer » 02 Jul 2018, 4:09 pm

Stix wrote:points of difference that may be of interest...
*the obvious of the .010" jump between the two.
*There is only .003" MAX difference in the shoulder measurement of the cases (from FLSized to formed-with the FL Sized being from the die wound ALL the way down to the shell holder), but most of the cases are only .0015"-.002" difference in the shoulder measurement from FL sized to fully formed.-other rifles i have in same chambering are atleast .0045" difference in the shoulder to head length.
*it is a very short chamber compared to the other few 22-250 chambers ive measured.
*I didnt do an actual water volume test on the cases to see the volume difference of before & after being sized/formed to get a true constant to measure from.


When loading these rounds, the neck-sized brass fills to 90-thou below the case mouth. The FLS'ed brass overfills the case, so I have to flick the case with my finger to get the powder to settle before I remove the funnel.
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