Neck sizing for accuracy

[foul bore]

you guys just saved me some $ on dies. very good info. good to hear from experience I do have a concentricity gauge that I use at times, and have seen more consistent groups with checking than without Thanks for your input. I will stay with fl sizing

 

[foul bore]

Thanks for your valuable input. saved me time and money. I will stay with FL resizing I do have a concentricity gauge I need to use more

 

[aushunter1]

So from the answers & info supplied NK sizing contributed no more or less accuracy than FL sizing.
But what about the concentric factor then which I think the OP was trying to improve.

Do you guys think concentricity plays a role in accuracy & how do you improve it?

 

[bigedp51]

"a full-length sized case in which the neck is also fully sized. There is clearance at the neck and in the body of the case, the closest fit anywhere is the bullet in the throat. If the neck to bullet concentricity is good (although it needn't be perfect), then the bullet will find good alignment in the throat and the case body and neck will have minimal influence. Let's not forget that the base of the case is supported by the bolt face or the extractor to a certain degree as well; this is yet another influence on alignment. As you can see, there are several points from base to bullet that can have an effect. My procedure is to minimize the influence of those that I can control, namely the case body and neck, and let the alignment be dictated by the fit of the bullet in the throat and to some extent by the bolt's support of the base. Barring a seriously out of square case head, I don't think the bolt can have a negative effect on alignment, only a slightly positive effect from minimizing "case droop" in the chamber. Given that a resized case will usually have a maximum of 0.001" diametrical clearance at the web, this isn't much of a factor anyway.

In conclusion, I believe that allowing the bullet to find a relatively stress-free alignment in the throat by full length sizing (including the neck) and turning necks to enhance concentricity gives the bullet the best probability of a well-aligned start into the rifling."

The Rifleman's Journal
Germán A. Salazar

 

[elf]

I FL size by bumping the shoulder back .002" every time and anneal necks every other firing.

 

[Alex Wheeler]

One thing I can tell you for sure, is that if your shooting a group and the bolt closes differently due to a tighter fitting case that shot will go out of the group. You can even see it on the crony. Full length sizing brings consistency. It also allows the bullet to center itself in the freebore without influence from the case. I do not know anyone that still neck sizes only.

 

[Ernie]

does neck sizing only on brass fired in ones rifle improve accuracy by making the loaded shell square in chamber (concentricity). looking for consistency.

My advice is to full length resize properly. I prefer to use a bushing neck, so I can control the neck tension as well. Seating dies are important too, if you are striving for the best accuracy possible or the least amount of run-out. Wilson type inline seat dies with an arbor press will take about another thou out compared to the better screw in die seaters.
It kind of also depends on how capable is your rifle, and how capable are you when shooting from hunting positions/field positions under stress. Putting the bullet where you want it is a systems approach, of which the shooter himself is part of the equation.

 

[CatShooter]

The br guys are 99% on board with fl sizing. I use to neck size, but now fl. Whatever works for ya.

The reason benchrest shooters now use FL sizing has nothing to do with accuracy... it has to do with shooting style.

BR shooting has broken into two camps. The "group size" camp, and the "score" camp.

Originally, all BR shooting was "Group". It was easy to measure the group size in the beginning, a steel tape measure was good enough. Then, a vernier was needed, then a vernier with a magnifying glass was needed.

But the darn groups kept getting smaller and smaller, until most local matches were having shooters getting groups in the 0.15" to 0.12" range. Then several judges need to estimate the size and the average was the "official" group size, and people were constantly arguing about the measurements so nothing could move forward until 12 guys measured Ol' Charlie's target.
It took so long to measure the targets that it got impossible to hold a match.

So, "Score" BR evolved. It was easy peasy - five targets, one shot in each target, with standard scoring rings and a teeny dot in the middle for an "X". No arguments about what the score was.
It was possible to shoot a "perfect score" with a rifle that shot 0.3" groups, which would get you laughed off the shooting line at any real "Group" BR match.
Hell, 7 of my 9 woodchuck rifles shoot better than that!

Because Score BR matches are so easy to run, almost no one holds group matches any more - the closest Group matches from my home (in central Connecticut) is a 9 hour drive, so I don't shoot bench rest any more - my BR rifles are now in field stocks.

Almost all "group" BR shooters use neck sizing, or special dies that do not size the body, only the neck and "maybe" touch the shoulder.

The thing about Score shooting is it is done real fast. You go to watch a Score BR match and you see 8 million wind flags on the field, and hardly any shooting, until the wind gets steady, then, holy crap, it is a battle field, with shooters shooting their whole 5 shot string in 15 to 20 seconds, and praying that they got lucky.

With this kind of shooting, there can be no tightness of the case in the chamber - the round must slip in the chamber like a "rat turd into a violin case", or the rifle might shift in the sand bags and all is lost cuz it must be reset in the bags, and by then, the wind has changed.

If you neck size and anneal from time to time, your cases will last forever - which might mean something when premium brass can go for a buck or more each, and you spend a lot of time trimming, annealing and fireforming them.

If you FL size your cases with standard FL dies, you WILL get head separations at some point, it is inevitable.

 

[338 dude]

Imo neck sizing is more about preserving your brass by reducing case hardening & not working the whole case.
In saying that you still need to anneal.
The amount of 'runout' produced in any sizing process using comes down to the quality of the dies.
A lot(probably most) BR shooters remove the expander from even their top quality dies & use a specific sized mandrel to give a specific amount of neck tension but also to improve concentricity.
I would also say neck turning would also assist in this, which is why they(BR shooters) do both processes.

Using the mandrel in place of the dies rod improves alignment.

Still, you really need to get yourself a concentricity gauge to measure all this otherwise there is no point.

You pretty much describe my loading processes exactly my brass lasts extremely long and I never have any issues as far as hard chambering or stuck brass I know other people have this is just my results

 

[sturner]

I use to neck size then started having problems chambering a round went to full length and no problem after that

 

[Gater]

I neck size my .223 bolt gun and use only Norma and Lapua brass and keep the two separate. When reloading for the mouse gun I FL size and use only military brass and I'll keep the same couple hundred brass until the case mouth start to show ware then scrap the whole lot and start another batch I have never had a head separation with either but when we where shooting a lot of service rifle matches the guys shooting the M1A and that was 99% of the booger's at the time they had problems with head separations after about 4-5 loadings

 

[Gater]

I nec

So from the answers & info supplied NK sizing contributed no more or less accuracy than FL sizing.
But what about the concentric factor then which I think the OP was trying to improve.

Do you guys think concentricity plays a role in accuracy & how do you improve it?

i neck size and use a Forster Ultra Micrometer seating die when I check run out they are within 00.1

 

[Pointman]

Back in the stone age, I was starting to load for a newly assembled 25-06. I had a gunsmith fit a new target grade barrel and inlet a thumb hole stock. The rifle showed promise for the task it was designed for, long-range ground squirrel shooting. I had a friend with a cattle ranch who was losing cattle with broken legs from squirrel tunnel collapsing. He gave me the run of the ranch. The dies I got were standard FL RCBS dies. I read an article about precision loading and the author recommended what he referred to was "partial" sizing. When setting the dies up, he recommended pitting a dime on the shell holder and then screwing the die down to that point and lock it down. I believe this gave what is now referred to a bump sizing just setting the shoulder back and still getting the case sizing benefit from FL sizing. This worked for me and gave me extremely good brass life. This was in the time when I had to use a trim die to reform old military 30-06 surplus brass to 25-06. I typically got brass life in the low teens. Granted I wasn't "hot rodding" the loads just looking for the best group. I carried this process forward till this day.

 

[Riflehunter1776]

The reason benchrest shooters now use FL sizing has nothing to do with accuracy... it has to do with shooting style.

BR shooting has broken into two camps. The "group size" camp, and the "score" camp.

Originally, all BR shooting was "Group". It was easy to measure the group size in the beginning, a steel tape measure was good enough. Then, a vernier was needed, then a vernier with a magnifying glass was needed.

But the *Rule 4 Violation* groups kept getting smaller and smaller, until most local matches were having shooters getting groups in the 0.15" to 0.12" range. Then several judges need to estimate the size and the average was the "official" group size, and people were constantly arguing about the measurements so nothing could move forward until 12 guys measured Ol' Charlie's target.
It took so long to measure the targets that it got impossible to hold a match.

So, "Score" BR evolved. It was easy peasy - five targets, one shot in each target, with standard scoring rings and a teeny dot in the middle for an "X". No arguments about what the score was.
It was possible to shoot a "perfect score" with a rifle that shot 0.3" groups, which would get you laughed off the shooting line at any real "Group" BR match.
Hell, 7 of my 9 woodchuck rifles shoot better than that!

Because Score BR matches are so easy to run, almost no one holds group matches any more - the closest Group matches from my home (in central Connecticut) is a 9 hour drive, so I don't shoot bench rest any more - my BR rifles are now in field stocks.

Almost all "group" BR shooters use neck sizing, or special dies that do not size the body, only the neck and "maybe" touch the shoulder.

The thing about Score shooting is it is done real fast. You go to watch a Score BR match and you see 8 million wind flags on the field, and hardly any shooting, until the wind gets steady, then, holy crap, it is a battle field, with shooters shooting their whole 5 shot string in 15 to 20 seconds, and praying that they got lucky.

With this king of shooting, there can be no tightness of the case in the chamber - the round must slip in the chamber like a "rat turd into a violin case", or the rifle might shift in the sand bags and all is lost cuz it must be reset in the bags, and by then, the wind has changed.

If you neck size and anneal from time to time, your cases will last forever - which might mean something when premium brass can go for a buck or more each, and you spend a lot of time trimming, annealing and fireforming them.

If you FL size your cases with standard FL dies, you WILL get head separations at some point, it is inevitable.

EXACTLY! THANK YOU!