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neck sizing
- Thread starter jd300rum
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Pretty well explains that!!
Gunpoor
Well-Known Member
The only time I have ever seen an advantage to neck sizing was with a belted magnum cartridge. The brass was severely over worked by a full length sizing die and I opted for neck sizing and it worked out very well. I have never seen any advantage to neck sizing any other cartridge I have loaded for and the list is very long.
bigedp51
Well-Known Member
- Joined
- Dec 10, 2010
- Messages
- 1,022
With a full length resized case the body of the case does not touch the chamber walls. In fact the only part of the case that touches the chamber is the shoulder. This is because the ejector pushes the case forward until case shoulder contacts the shoulder of the chamber.
With a full length resized case the rim is held and supported by the bolt face and by the bullet in the throat. Meaning the case body has no guiding or misaligning effect with the bullet and the bore. (the rat turd in the violin case)
German Salazar had a very good write up about this at his "Rifleman's Journal" but I'm sorry to say his website was shut down.
With a full length resized case the rim is held and supported by the bolt face and by the bullet in the throat. Meaning the case body has no guiding or misaligning effect with the bullet and the bore. (the rat turd in the violin case)
German Salazar had a very good write up about this at his "Rifleman's Journal" but I'm sorry to say his website was shut down.
Wedgy
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- Joined
- Feb 9, 2013
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- 3,278
The idea in reloading is to keep everything the same every time. With neck sizing only you will eventually have to resize the whole case and then you changed something in the process. I think a lot of people feel that by "full length" they really mean just bumping the shoulder back about 0.002" and neck sizing. Measure 5 fired cases from base to shoulder then set your die up so it bumps that measurement back 0.002", and adjust the neck bushing on how much of the neck you want sized, and what bushing for how much neck tension you want. This way you are not over working the brass. If you set the die all the way down to the shell plate it may push the shoulder back way more and you would overwork the brass unnecessarily. Annealing the cases every couple firings is beneficial as well.
Others may chime and add as well, lots of info on this topic here
Others may chime and add as well, lots of info on this topic here
Mikecr
Well-Known Member
You've heard one side, let me provide you a little more.
To begin, much of it depends on the cartridge design, the load pressures you choose to run with, your control over the chamber and dies, and your reloading understanding and attention.
-To begin, FL sizing includes full body, full shoulders, and full necks, at the same time. It's not full body, full shoulders, and bushing partial neck sizing(that's body-bushing sizing). Each of these sizing actions can be handled separately with applicable separate dies. A body die, a bump die, a neck die, various customs.
So given merchandising misnomers here, there can be more to the question of NS -vs- FL sizing.
-If you're reloading a 30-06,, 308, 270, 243, (and many similar) then yes you'll have to size full body & shoulders, and you'll be trimming the case away to changing capacities, and creating bigger loaded ammo runout. These case designs are as far from 'improved' as it gets.
-Runout is caused by and builds with sizing. The greater the sizing area, the greater the frequency of sizing, the greater your runout will end up. When you build & chamber bananas, they do not float centered in that chamber. Here there is no 'just touching the shoulder' with everything centered. With chambered runout, you get chambered tensions that affect system vibrations(like a thumb resting against the action tang on firing).
So bananas in tighter chambers don't perform as well. Folks who produce & shoot bananas notice better results with sloppy chambers, and we end enduring 'rat turd in a violin case' notions, implying that this condition is a must.
I'm glad it's not a must for me, as I make straight ammo, because I don't EVER FL size.
So,, in extremes,, you could actually choose an improved chamber tight enough(fitted) that brass will never need to visit a sizing die, producing zero runout. Or,, you go sloppy and big in sizing to create massive chamber clearances. But neither is free.
-Back to actual FL sizing; you don't ever want to FL size necks. For hunting capacity cartridges there is nothing good and only bad about this. It's a matter of consistent neck tension, which larger to overbore cartridges are sensitive to. Relatively tiny for cal underbore cartridges rely on high peak pressure(beyond viable for hunting cartridges) to work-around many things (performing relatively better). High neck tension provided by FL sizing of necks, provides for high peak pressures, which is a work-around even for high tension variances. There are high dollar body dies that include combined neck/shoulder bushings well suited for underbore cartridges.
-Trimming. FL sizing leads to trimming. What do you think it means when trimming brass away at the case mouths? Do you think it's free of cost?
Two things it means for sure: The underfitting case grew to a point of yield on firing, and you had to FL size (again, a lot) for rechambering.
FL sizing begins near case webs and rolls brass thickness up the body, into shoulder, into neck shoulder junction(donut), and into necks(where you trim it away). Like squeezing toothpaste. If you want to consider consistency, then you shouldn't see this as contributing. It doesn't.
Your case capacity has just grown by an amount laying in a pile on your bench. Your donut has grown, and could affect your neck tension. Hey, that leads you right to the constant annealer crowd... Another must. On firing, the case itself yeilded, stretching to chamber walls so far away, and yielded brass doesn't spring back so much, leaving interference fitting extraction, leaving you to think you need a small base die(more sizing), and it goes roundy-roundy.. But you work harden brass with so much sizing, so it takes more pressure to expand back to yielding & against chamber walls, and this affects timing of your peak pressure. Again, don't see this as consistent. It isn't.
Well, that's just some things I wanted to throw out there about it.
I could lay out costs in every type of sizing plan.
But no matter our plan, we can be successful or not, since some of it is out of our control, and therefore some of it is LUCK.
I come into an occasion where I tested off the shelf factory ammo shooting as well as my reloads. This is mind boggling to me still. But then again, I've yet to see it shoot BETTER than my reloads. And I haven't FL sized since I was 12yrs old(in a reloading class, 40yrs ago).
To begin, much of it depends on the cartridge design, the load pressures you choose to run with, your control over the chamber and dies, and your reloading understanding and attention.
-To begin, FL sizing includes full body, full shoulders, and full necks, at the same time. It's not full body, full shoulders, and bushing partial neck sizing(that's body-bushing sizing). Each of these sizing actions can be handled separately with applicable separate dies. A body die, a bump die, a neck die, various customs.
So given merchandising misnomers here, there can be more to the question of NS -vs- FL sizing.
-If you're reloading a 30-06,, 308, 270, 243, (and many similar) then yes you'll have to size full body & shoulders, and you'll be trimming the case away to changing capacities, and creating bigger loaded ammo runout. These case designs are as far from 'improved' as it gets.
-Runout is caused by and builds with sizing. The greater the sizing area, the greater the frequency of sizing, the greater your runout will end up. When you build & chamber bananas, they do not float centered in that chamber. Here there is no 'just touching the shoulder' with everything centered. With chambered runout, you get chambered tensions that affect system vibrations(like a thumb resting against the action tang on firing).
So bananas in tighter chambers don't perform as well. Folks who produce & shoot bananas notice better results with sloppy chambers, and we end enduring 'rat turd in a violin case' notions, implying that this condition is a must.
I'm glad it's not a must for me, as I make straight ammo, because I don't EVER FL size.
So,, in extremes,, you could actually choose an improved chamber tight enough(fitted) that brass will never need to visit a sizing die, producing zero runout. Or,, you go sloppy and big in sizing to create massive chamber clearances. But neither is free.
-Back to actual FL sizing; you don't ever want to FL size necks. For hunting capacity cartridges there is nothing good and only bad about this. It's a matter of consistent neck tension, which larger to overbore cartridges are sensitive to. Relatively tiny for cal underbore cartridges rely on high peak pressure(beyond viable for hunting cartridges) to work-around many things (performing relatively better). High neck tension provided by FL sizing of necks, provides for high peak pressures, which is a work-around even for high tension variances. There are high dollar body dies that include combined neck/shoulder bushings well suited for underbore cartridges.
-Trimming. FL sizing leads to trimming. What do you think it means when trimming brass away at the case mouths? Do you think it's free of cost?
Two things it means for sure: The underfitting case grew to a point of yield on firing, and you had to FL size (again, a lot) for rechambering.
FL sizing begins near case webs and rolls brass thickness up the body, into shoulder, into neck shoulder junction(donut), and into necks(where you trim it away). Like squeezing toothpaste. If you want to consider consistency, then you shouldn't see this as contributing. It doesn't.
Your case capacity has just grown by an amount laying in a pile on your bench. Your donut has grown, and could affect your neck tension. Hey, that leads you right to the constant annealer crowd... Another must. On firing, the case itself yeilded, stretching to chamber walls so far away, and yielded brass doesn't spring back so much, leaving interference fitting extraction, leaving you to think you need a small base die(more sizing), and it goes roundy-roundy.. But you work harden brass with so much sizing, so it takes more pressure to expand back to yielding & against chamber walls, and this affects timing of your peak pressure. Again, don't see this as consistent. It isn't.
Well, that's just some things I wanted to throw out there about it.
I could lay out costs in every type of sizing plan.
But no matter our plan, we can be successful or not, since some of it is out of our control, and therefore some of it is LUCK.
I come into an occasion where I tested off the shelf factory ammo shooting as well as my reloads. This is mind boggling to me still. But then again, I've yet to see it shoot BETTER than my reloads. And I haven't FL sized since I was 12yrs old(in a reloading class, 40yrs ago).
Yep! I've done both but now I'm back to FL; my gun builder does the same.
I tried the neck sizing and really liked the snug fit in the chamber it gave. I don't think I definitively proved that neck sizing had much to do with my accuracy (probably the shooter) but it did see some better case life due limited FL sizing. However, I would always end up having to FL size after 2 or 3 shootings as the case near the bottom would become to large and would not fit in the chamber. I've since sold all but one of my neck sizing dies and focus more on the shoulder bumping with a FL size die. I've started into the S dies and love them to better control neck tension.
Total misconception at best to say FL sizing necks leads to higher pressure. Too much neck tension can be caused by NS also if too much tension. Too much tension is not caused by a sizing method.
Only Mikecr has invented his definition of FL sizing being given done all at one time. No one else says that. A case is FL sized whether done in one step or 3. All the same. Plus body sizing and then NS is not the standard definition of NS.
Only Mikecr has invented his definition of FL sizing being given done all at one time. No one else says that. A case is FL sized whether done in one step or 3. All the same. Plus body sizing and then NS is not the standard definition of NS.
