Neck Sizing Vs. Full Length Sizing and Neck Tension

[FullCurl8]

So did the originator get the scientific data to support neck sizing only where brass life is the number one concern on belted magnums? In my 7 STW when using softer brass, ie Nossler, 3 firings and cases were garbage. Neck sizing more than doubled the life of the cases to about 7.
Accuracy has always been 1/2 minute of sheep, or 3/4 moa.

 

[SSG Graybush]

The same as AZ-SHOOTER except I anneal every time.

Yes, you should anneal every firing imo. Keep it as consistent as possible.

 

[Ol'Gator]

Having loaded any number of belted case calibers, including 7mmSTW, the use of belted magnum collet resizing die allows a good many reloads not normally found without this die.

 

[300RUM LNGRNGE]

I have not guaged the head space, but the Encore is a breach loader, so I don't know how that may factor into it.
Once I began having all the case head separations, I did google this online and what I found was it was fairly common and fairly widely reported in belted magnums that are full length resized. Most report only 2-3 firings before failure of the brass because its being worked back and forth so much and fatigues at the juncture just above the belts on the belted magnums. The metal gets shoved down until it hits the belt and has no where to go, then it gets elongated from that same point in the next firing. The best idea I heard here was to full length resize with a .002 shoulder bump that may ease some of the back and forth further down the case at that juncture. So, I will try that. If it doesn't work, I will then have no choice but to go back to neck sizing only on belted magnums I suppose....

I have a little experience with the TC breech loading rifles. Friend of mine brought one to me that was not firing because it had excessive head space. Fixed it with this.
https://www.bellmtcs.com/product/en...ction-of-headspace-up-to-.020.#product_detail

He has some great insight into these rifles, but as it would turn out , head spacing is a pretty common problem with these rifles.

Have had a belted magnum rifle for years, full length resized entire time, was never had case seperation.
Not saying that this is your problem, but maybe should be looked into.

Good article on head spacing for these models http://www.lasc.us/bellmHeadspace.htm

 

[300RUM LNGRNGE]

Good article, sending link only for information, not suggesting you purchase anything.

 

[300RUM LNGRNGE]

Another good article.
Especially the 5th paragraph.

Understanding Headspace

This reloading article shows how to headspace your handloads correctly. It also explains why our Belted Magnum Collet Resizing Die is needed.

larrywillis.com

These couple things could explain why full length resizing doesn't work for you.
If this is the reason, maybe the answer for your situation is to neck size.

Again, information only.

 

[WapitiBob]

BoomFlop, I have seen mention of the shell holder kir before but did not pay much attention to it.
How is it different than adjusting the die up or down? I can see where changing the shell holder to get a setting faster without trial and error. Is that the primary function...fast, precise changes?
Sorry for my lack of knowledge on this.

The competition shell holder has the same outer thickness as a regular shell holder (so you can get cam over) but the inner portion where the case head sits is different thickness for each insert.

 

[Keith M Sheehan]

I agree with a lot of things and suggestions that everyone has mentioned. I hand load for 46 different calibers, and have been doing it since 1958. My choice is to use FL dies, but to size them only far enough to fit into the action. If I am sizing belted cases, I want the belt and the neck to both touch the chamber, so I usually size about 80-90% of FL. The case not only slips back into the chamber snugly, but the partially sized neck centers in the chamber. Straight walled cases usually fit back into the chamber at around 75-85% of FL. Handgun cases are usually sized 95%. In re-sizing like this, I get maximum case life and excellent, uniform accuracy. Each chamber requires individual attention and experimentation for optimum results. The only exception is sizing cases for multiple guns in the same caliber. I have 4 .30-06's and must size all my cases so they fit in the tightest gun.

 

[Tulsa Reiner]

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!

My reaction, without having read all 12 pages of this thread: were you measuring shoulder bump, and limiting it to 0.002" or less, on those 300WM cases?

 

[Tulsa Reiner]

Regarding the locking rings on your RCBS dies: the RCBS locking rings are a big problem because they lock with a brass set screw that applies tension to the threads of the die. They don't hold and the ring slips. I had to replace all of mine with Lyman locking rings that lock with a set screw that constricts the ring on the die threads. This design really has held the locking ring position well for me. They are about $7 apiece, and well worth the money. Hornady and Forster make similar split lock rings.

 

[Philward]

Regarding the locking rings on your RCBS dies: the RCBS locking rings are a big problem because they lock with a brass set screw that applies tension to the threads of the die. They don't hold and the ring slips. I had to replace all of mine with Lyman locking rings that lock with a set screw that constricts the ring on the die threads. This design really has held the locking ring position well for me. They are about $7 apiece, and well worth the money. Hornady and Forster make similar split lock rings.

Agree, those rcbs lock rings are crappy, the set screws always strip out the drive portion and the wrench slips. The older round knurled ones they offered are better. I'm changing to some Hornady ones, mainly on the sizing dies.

 

[Valek]

Regarding the locking rings on your RCBS dies: the RCBS locking rings are a big problem because they lock with a brass set screw that applies tension to the threads of the die. They don't hold and the ring slips. I had to replace all of mine with Lyman locking rings that lock with a set screw that constricts the ring on the die threads. This design really has held the locking ring position well for me. They are about $7 apiece, and well worth the money. Hornady and Forster make similar split lock rings.

I introduced a small lead shot in front of the set screw in each of my RCBS dies. That seems to have solved the problem for me...and it further protects the threads.

 

[Mike6158]

12 pages later. I've been load testing for my 7mm Rem mag with the same 30 cases. I'm on the 6th or 7th firing (at least). I anneal after every test. Full length size with a .003 shoulder bump, RCBS bushing die for the neck, and expander mandrel after that (.002 neck tension). I think the primer pockets will get too loose on me before the neck does. I can feel some of the primers taking less pressure to seat them. Finding brass has been a pita. Finding new brass was in impossipita (spell check fail).

 

[FullCurl8]

Your wasting good brass for the sake of only NK sizing. There's no reason to only neck size when it's been proven that proper FL sizing is just as accurate, ensures reliable feeding, and gives good brass longevity. As I stated before, I get 15+ reloads from belted mags.

So what kind of brass are you using that's giving 15 + reloads on Belted mag Full Length Resizing? Are these full powder charges, Max, Min. I tend to always run on the warmer side of things and never seen 15, 8 is more likely for the 300 Full Length Sized