Neck Sizing Vs. Full Length Sizing and Neck Tension

[TXTrained]

Ok, I don't want to start a food fight or anything, but I am curious what everyone on this forum has to say about this subject. I've seen the Erik Cortina video where he says neck sizing is just passe and so much old lore, and to just full length size for consistency. I've seen some other videos on youtube which sort of cite him and say they agree. However, in my own experience, I haven't so much run the tests to match up one method against another, its just that I learned the hard way you CANNOT full length size belted magnum cartridges past 2-3 times without head case failures. At least I could not. I had 6-7 head case failures on my .300 win mag. which of course is a belted magnum. I even had one lower half stay in the chamber so tight, I had to fill it with earplugs, then fill with an epoxy, and then ram it out from the barrell end.......not fun. So, now I neck size all my new Peterson Brass and have had no more issues or failures and I'm up to 5 times on that brass. Full length sizing at least with my RCBS dies just overworked the brass shoving it back down on the belt, and then the firing would stretch it back out until it failed above the belt in case head separation due to metal fatigue. No one ever told me not to Full length size belted cartridges, no book, no article, nobody told me. I had to learn the hard way.

But, I do full length size my .338 Lapua Magnum brass every 2-4 firings now, and neck size it the rest of the time, just to try to get a little more life out of it. I think just anecdotally I see better group sizes on it when I neck size it. I haven't run any real tests yet. Is there any real scientifically consistent and valid data run by anyone you can point me to who has done exhaustive testing on this subject as to group size vs. method?

Next, I've seen some videos by sdkweber and bolt action reloading on youtube where they ran some tests that seemed to indicate that either 2 thousands or 3 thousands neck tension is optimum for shooting small groups. Is there an accepted standard in the community and if so what is it, and can you again point me to any definitive studies that are scientific, exhaustive, and consistently run that says what the answer is?
One guy says 2 thousands works best, and another seemed to end up with a relationship what shows 1 thousands is worst, 2 thousands is better and 3 thousands is best in a curvelinear line that shows diminished gains at the 3 thousands mark, ie not much to be gained if any past that.
Does anyone have a magic wand or a crystal ball?

I'm just digging in and trying to get it right!

I shoot both..In ELR matches.
Now for ERIK or any of theBenchrest or F-Class Shootersthey full thength size .One of the reasons is they want their bolt to open and close without any pressure .So they do now disturb the gun in anyway.
My experience with Neck VS Full Length is as long as I do one or the other things are consistent.If the cartridge fits into the chjamber with much effort to open and close the bolt I dont care.The neck tyension is allI care about.I do not mix Neck & Full Length in a string of firfe or in a batch of reloading.At some point I will have to Full Legth Size.Erik said Why swap around. Well thats apopint.Iam in theprocess of getting a AmpAnnealer & Amp Press.I will probably FullLength SDize ,The neck sizing is much faster and cleaner for me though.

 

[misterc01]

I neck size my fire-formed brass and even after viewing the Cortina videos, and see no reason to change. It works for me.

 

[Mikecr]

I neck size my fire-formed brass and even after viewing the Cortina videos, and see no reason to change. It works for me.

Independent thought seems amazing today.

 

[Mike Matteson]

I was losing belted Mag case in about 3 or 4 firing. I change to only neck sizing the cases. That stop the case base separation. I used a 300WM neck sizing die for my 308NM. The neck on the 308NM is longer and to the shoulder is shorter. So it only sized 2/3 of the neck. If I had problem with the case not being allow to be chamber, then I would FL size them. I have been setting up to FL again but only bumping the should back a thousand or two.

 

[TXTrained]

I have felt like saying this many times and maybe someone else has already said it.Im sure some have THOUGHT IT TOO.
When these Pro guys,I will just use Erik Cortina as an Example.... So Erik say they are telling us everything they do.I think have of it is they are telling the truth & haveis they are Blowing Smoke and giving us just enough to keep us interested and watching his channel.They dont want to lose all that Pateron moneyor YouTube money.Im quite sure its a considerable amout.It has to be..He is not pouring concrete and building Barndominiums full time anymore..He cant be.He is always gone shooting or making videos.And if he can make a good living of thise things Power To Him,.He isnt packing a lunch box to work anymore.And he has done well with his machine shope business.
So back to trhe Smoke Screen...To prove it ,You can hear him on his videos..say to another Pro shooter &/or bigtime YouTuber that its a secret..Or Can I say that..You can catch them catching themselves like they have divulged too much info..I tip my hat to him.He has figured lout hpow to get paid doing what he loves..Thatys a great life.

 

[Joe-boy]

I'm still looking for the best way as a relatively fresh reloader. I've seen the Cortina videos and I think he most likely has a good point. On the other hand, it's just way faster and easier to neck size. I'm using the Lee collet die and a Lee full length resizing die. My rifles have relatively loose standard CIP mass produced chambers. I've just been learning to adjust according to shoulder bump instead of the default instructions, but it still appears that the case elongation is much more of an issue when full length resizing.

Case prep with neck sizing:
-Resize
-Measure

Case prep with full length resizing:
-Lubricate
-Resize
-Measure
-Trim
-Deburr

...so it saves time and hassle to just neck size and I've never had an issue with just neck sized ammo. Time will tell if I manage to adjust my full length resizing die so that there is no need to constantly trim the cases. I've been told eventually you anyways need to full length resize, so I see the benefit of doing it constantly instead of every once in a while.

 

[436]

I'm still looking for the best way as a relatively fresh reloader. I've seen the Cortina videos and I think he most likely has a good point. On the other hand, it's just way faster and easier to neck size. I'm using the Lee collet die and a Lee full length resizing die. My rifles have relatively loose standard CIP mass produced chambers. I've just been learning to adjust according to shoulder bump instead of the default instructions, but it still appears that the case elongation is much more of an issue when full length resizing.

Case prep with neck sizing:
-Resize
-Measure

Case prep with full length resizing:
-Lubricate
-Resize
-Measure
-Trim
-Deburr

...so it saves time and hassle to just neck size and I've never had an issue with just neck sized ammo. Time will tell if I manage to adjust my full length resizing die so that there is no need to constantly trim the cases. I've been told eventually you anyways need to full length resize, so I see the benefit of doing it constantly instead of every once in a while.

Just out of curiosity, whose dies are you using? The second question is; have you ever thought about the RCBS X-die? Cheers

 

[Joe-boy]

Just out of curiosity, whose dies are you using? The second question is; have you ever thought about the RCBS X-die? Cheers

Lee's dies and no, I haven't.

Earlier I adjusted my FL resizing dies according to the instructions, which produces a brass that fits in any chamber. Now I've switched to resizing only slightly to bump the should slightly back, but I haven't fired the same cases often enough to actually see how much trimming is needed.

For hunting ammo I've always resized fully because I want the extra reliability it provides. For practice ammo I am tempted to only neck resize as it stresses the cases less and the brass prep procedure is faster and easier.

 

[ncwg2boatguy]

Well, I must say bumping the shoulder back a little to make the belt seat better so there is not excess head space left over after the cartridge elongates after firing makes some sense to me. I am sure willing to try that. It's just a step further than I have gotten in my reloading. Are there specific dies anyone recommends that are easy to set up for FL sizing with a shoulder bump that works well?
I'm not sure that my standard RCBS dies will set up to do a shoulder bump unless its just a matter of experimenting with the distance the cartridge gets pushed up into them? Let me know what you recommend to do this. I plan to try it. I can also see that annealing with this working the shoulder is gonna be more important. Thanks for your help.

Buy the Redding bump shell holders. Easy day. They sell them from .002-.010 bump

 

[C-130 Dude]

Ok, I don't want to start a food fight or anything, but I am curious what everyone on this forum has to say about this subject. I've seen the Erik Cortina video where he says neck sizing is just passe and so much old lore, and to just full length size for consistency. I've seen some other videos on youtube which sort of cite him and say they agree. However, in my own experience, I haven't so much run the tests to match up one method against another, its just that I learned the hard way you CANNOT full length size belted magnum cartridges past 2-3 times without head case failures. At least I could not. I had 6-7 head case failures on my .300 win mag. which of course is a belted magnum. I even had one lower half stay in the chamber so tight, I had to fill it with earplugs, then fill with an epoxy, and then ram it out from the barrell end.......not fun. So, now I neck size all my new Peterson Brass and have had no more issues or failures and I'm up to 5 times on that brass. Full length sizing at least with my RCBS dies just overworked the brass shoving it back down on the belt, and then the firing would stretch it back out until it failed above the belt in case head separation due to metal fatigue. No one ever told me not to Full length size belted cartridges, no book, no article, nobody told me. I had to learn the hard way.

But, I do full length size my .338 Lapua Magnum brass every 2-4 firings now, and neck size it the rest of the time, just to try to get a little more life out of it. I think just anecdotally I see better group sizes on it when I neck size it. I haven't run any real tests yet. Is there any real scientifically consistent and valid data run by anyone you can point me to who has done exhaustive testing on this subject as to group size vs. method?

Next, I've seen some videos by sdkweber and bolt action reloading on youtube where they ran some tests that seemed to indicate that either 2 thousands or 3 thousands neck tension is optimum for shooting small groups. Is there an accepted standard in the community and if so what is it, and can you again point me to any definitive studies that are scientific, exhaustive, and consistently run that says what the answer is?
One guy says 2 thousands works best, and another seemed to end up with a relationship what shows 1 thousands is worst, 2 thousands is better and 3 thousands is best in a curvelinear line that shows diminished gains at the 3 thousands mark, ie not much to be gained if any past that.
Does anyone have a magic wand or a crystal ball?

I'm just digging in and trying to get it right!

Sometimes I think that this sizing thing is about what works for you. Belted cases are, IMHO, an exception to the full sizing rule(?). I have similar sizing problems with my 300wm. I neck size all new and used cases now. Only full length them when it is a last resort. And get ready for the headache! Now with the non belted cases, I full length w/neck size all of them. All the time. It works for me and my cases typically last between 5-10 resizes.

 

[Veteran]

Sometimes I think that this sizing thing is about what works for you. Belted cases are, IMHO, an exception to the full sizing rule(?). I have similar sizing problems with my 300wm. I neck size all new and used cases now. Only full length them when it is a last resort. And get ready for the headache! Now with the non belted cases, I full length w/neck size all of them. All the time. It works for me and my cases typically last between 5-10 resizes.

Yep, I dont think I want to do both full length and neck sizing.
Seems to me the whole reason that one gets case head failures
on belted cartridges is overworking the brass and it fatiques right above the belt.

I am trying to bump my shoulders as many here have recommended and see how much life extension I get that way.

Any process that is shoving the brass back down on the belt over and over though will cause failures.....

 

[C-130 Dude]

Yep, I dont think I want to do both full length and neck sizing.
Seems to me the whole reason that one gets case head failures
on belted cartridges is overworking the brass and it fatiques right above the belt.

I am trying to bump my shoulders as many here have recommended and see how much life extension I get that way.

Any process that is shoving the brass back down on the belt over and over though will cause failures.....

Yeah I know your pain. If you do need to size your case bodies, you don't have to do both sizing processes seperatly. I use the RCBS match master dies. The one I use does a full length size and does a neck size at the same time. After you measure your neck thickness, you put a neck bushing in the die. When you run the press, it does a full length size and shapes neck to the size you select with the neck bushing. Easy and works well for me. (I use this but I get no money and no skin in the game from RCBS.) Also, you can use things to making bumbing size easier by using a die that allows micrometer depth settings. Or like me, I use a click micrometer die lock such as from Whidden. These are real time savers. You can adjust seating die depth, sholder depth, trimming depth (works great on my Garaud), and a couple I haven't tried yet. This one has saved me tons! Again no money received, no skin in the game. Just works well.

 

[Veteran]

Yeah I know your pain. If you do need to size your case bodies, you don't have to do both sizing processes seperatly. I use the RCBS match master dies. The one I use does a full length size and does a neck size at the same time. After you measure your neck thickness, you put a neck bushing in the die. When you run the press, it does a full length size and shapes neck to the size you select with the neck bushing. Easy and works well for me. (I use this but I get no money and no skin in the game from RCBS.) Also, you can use things to making bumbing size easier by using a die that allows micrometer depth settings. Or like me, I use a click micrometer die lock such as from Whidden. These are real time savers. You can adjust seating die depth, sholder depth, trimming depth (works great on my Garaud), and a couple I haven't tried yet. This one has saved me tons! Again no money received, no skin in the game. Just works well.

ok, well this makes more sense.
You are just doing a full length size with a bushing die that sizes the neck for neck tension.

Its just like the Forester dies that are bushing dies.

 

[Buck Fever]

A benchrest shooter is going to be running a tight chamber and headspace near 0.000". His brass shouldn't move much when firing and shouldn't move much when full length sizing.

I also think the sizing 1/2 the neck just helps when the necks are too thin so the bulge centers the case when chambering.

Another thing benchrest shooters always do is anneal between loadings. Softening the brass lets it flow evenly when sizing and firing. Brass that has been work hardened too much gets brittle.

Now if you have a loose chamber and full length size back to SAAMI spec, the brass could be moving a lot. Since it headspaces off the belt, you might never know that's happening.

That's the reason why I don't have any belted magnums and probably won't go there.

I don't mind a multi-step case sizing so I have a body die for my 338 RUM and a Lee collet neck sizer. That lets me adjust shoulder bump independently and since it headspaces on the shoulder, I can see how much the brass is moving with my case comparator.

You could do the same with a belted Magnum, it just takes a bit more measuring if you are trying to headspace off the belt.

If you do size for a loose chamber, make sure those rounds don't wind up in a gun with a tight chamber...