Neck sizing belted magnums

[dok7mm]

One thing I would point out is that belted magnums, especially with hotter loads, tend to swell right above the belt. This is most often seen in looser factory chambers. Most FL dies have a hard time sizing this area to allow chambering. Larry Willis invented the collet die to size this area and he's sold a bunch of them.

I come down on the side of proper FL sizing vs neck sizing, particularly in a factory chambered belted Magnum. Some really knowledgeable people say neck sizing will get it done, as that is their experience. I say, over time, you're better off FL, or a body die, for reliable chambering. Just my 2 cents.

 

[Mikecr]

I don't FL size cartridges,, but then I don't shoot large area cases with high body taper and low shoulder angles in factory chambers. If I did, I would FL size them, as it would not be long before it was required anyway. I plan otherwise.

Bushing or custom partial neck sizing works great(I'm sure best), but the necks should still be expanded, or 'pre-seated'. It is not excess to do so when you understand tension.
There is sound reasoning behind most die maker's recommended 2thou under loaded diameter for the bushing. This reasoning includes expected neck expansion to ~1thou after downsizing.
#1 Neck tension amounts to no more than spring back against seated bullet bearing, and max spring back is 1thou.
#2 Bullets should not be used as expanders.
#3 Expansion drives thickness variance outward, away from seating bullets.

I use Wilson neck dies, and couldn't recommend between the more expensive toys out there.
The Wilsons do not include an expander rod, and I would remove this if they did. Instead, I use Sinclair expander dies/mandrels in a separate operation.
My expander die is modified to include a load cell force measurement. With this, and careful control over friction(I leave the carbon layer alone), I establish matched pre-seating forces in necks before charging cases with powder.
This is not direct tension measure, which we have no way to do currently. But I'm confident that my necks are as consistent in tension as possible from my part.

 

[Barrelnut]

My expander die is modified to include a load cell force measurement. With this, and careful control over friction(I leave the carbon layer alone), I establish matched pre-seating forces in necks before charging cases with powder.

Mike,

I can definitely see the benefit here. Would love to know which cases had matching neck tension before I ever seated a bullet in them!

Would like to ask what type load cell you are using and how you incorporated it. I assume it is attached to the Sinclair expander die somehow?

Thanks.

 

[J E Custom]

The vast majority of modern bolt actions have a recessed bolt face and the cartridge does "NOT" lay in the bottom of the chamber

The only rifle I have ever owned that the cartridge did lay in the bottom of the chamber was the British .303 Enfield rifle with its flat nonsupporting bolt face.

Below is from the "Rifleman's Journal" website written by German A. Salazar in response to a question about partial neck sizing using a full length die.


Reloading: Partial Neck Sizing
by German A. Salazar
http://riflemansjournal.blogspot.com/2010/06/reloading-partial-neck-sizing.html

"Now the last scenario, 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."

I belong to the "rat turd in the violin case" club.

The trick to fire forming the British .303 cartridge in the large military Enfield rifles chamber and have the excess head clearance removed and "center" the case in the rear of the chamber was simple.

A small rubber o-ring was slipped over the case to hold the case against the bolt face. And when the rubber o-ring was compressed it flowed around the base of the case into the chamber and centered the case in the rear of the chamber.

Below the o-ring method of fire forming a rimmed case with a unsupported bolt face for my .303 British Enfield rifles.

Bottom line it is a misconception to say any "modern" rifle lets the cartridge "lay" in the bottom of the chamber.

I will have to disagree with everything you have said because=

1 = the recess bolt face cannot hold the round concentric because it is .007 to .010 thousandths larger than the case head in order to eject the case.

2 = The head space would have to be .0000 in order to hold the case head square with the bore.

3 = belted cases were designed to allow the case to head space correctly with lots of room around the case body so they will chamber even in the dirtiest chamber.

4 = When neck sizing only, a belted case fits the chamber and does not require the belt any more forcing the case to be pushed against the shoulder automatically aligning the front of the case and the bullet. leaving the body of the case alone it will automatically align the back of the case. And if the action has been properly trued the rim of the case will be centered in the bolt face and never touch any part of the bolt recess except the face.

5 = Jamming the bullet into the throat only aligns the bullet. If the loaded round is not perfectly concentric it throws the entire case off center and if the round is over sized it allows the back of the case to misalign even though it forces the case head back against the bolt face it will not automatically align its self perfectly and most of the time you can see this because the case will have a distinct bulge on one side more than the other. also most hunting rifles use magazine length for follow up shots so seating the bullets against the throat is not practical.

6 = also necks must have .003 to .004 thousandths minimum, to allow the neck to release the bullet without excessive pressure,so if the case body has been over sized it will lay in the bottom of the chamber.

Also, Most bench rest shooters don't size there cases at all they tight neck chamber the neck and turn the necks so that the fired case will just hold the bullet, and simply prime and charge the same case over and over for a match

I personally don't have anything against full length sizing and practice doing it on many Simi Auto
fire arms. But when accuracy is required, Everything has to fit the chamber perfectly and ammo must be as good and concentric as possible, and a full length sized case just does not fulfill these requirements.

My opinion comes from many years of shooting matches and building quality precision rifles and pistols that will shoot well under 1/4 MOA. If anyone thinks that a few thousandths one way or the other doesn't matter I recommend that they keep the shots under 5 or 600 yards where one minute of deer is good enough. neck sizing is not for everyone, but for those that want the best accuracy and don't mind taking the trouble to load near perfect ammo the rewards are accuracy.

You are entitled to your opinion and I am entitled to mine so we can leave it at that.

J E CUSTOM

 

[CatShooter]

BigEdP51...

You say:

"The vast majority of modern bolt actions have a recessed bolt face and the cartridge does "NOT" lay in the bottom of the chamber."

But it should be obvious that the modern bolt action rifle, because of it's spring loaded ejector, pushes the loaded round to the opposite side of the chamber.

This is why the case swelling in front of the web is not uniform around the case, but to one side - it is because the case was not centered. It is not a critical matter, because once the case if fired, the expanded body redefines the axial center, and you can go from there, unless you keep squishing the body back down, and starting all over.

--------------------------------

"Below is from the "Rifleman's Journal" website written by German A. Salazar in response to a question about partial neck sizing using a full length die."


Reloading: Partial Neck Sizing
by German A. Salazar
http://riflemansjournal.blogspot.com/2010/06/reloading-partial-neck-sizing.html

"[...] 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."

I belong to the "rat turd in the violin case" club.

The problem with this comment is... because of brass spring back, there will ALWAYS be ~0.001 clearance between the case body and the chamber with neck sizing - you don't need a FL die for that... and with 99% of "over the counter" FL dies, they will always create more "slop" (not clearance).

I belong to the "Snug as a Bug in a Rug" club.

There are several problems with Kevin Thomas' comments.

1 - "As I said, if done properly, F/L sizing gives you every bit as long of case life as N/S can,, but without all the additional headaches that go hand in hand with neck sizing.

The problem with that comment is this - I reloaded my first cartridge in 1953 (I AM older than dirt). I have been the chief manager of an ammunition company (twice - I left, they shut down, I came back. I left again, and they shut down for good). I owned my own ammunition company for 4 years. I am a NRA certified handloading instructor, and I have been teaching this stuff for a loooooong time. What I have found is this.

If you take 500 everyday handloaders (throw in 100 "accuracy" handloaders too, if you like), you will find maybe 10 to 20 that can properly set up an over the counter FL sizing die. The "PB Bench" kids pay $175 for a "custom" FL die, which is made so it can't be mis-adjusted, so they don't have to know doodley squat.

Maybe one in 500 reloaders has equipment to measure the headspace of cases and chambers, or shoulder growth when setting up a OTC FL die.... and less than one in 100, knows how to detect case stretching.

Head separation is a common aliment, but neck sizing causes none of this. In 1975, I bought a Remington 40-XB rifle in 22-250, a "deeeeelux set of RCBS dies, and 400 Winchester cases.
I burned out the barrel in a 3 week trip to South Dakota, over PD towns... we shot during the day, and we loaded at night. I neck sized. The cases fit snug (with some crush).

I got it rebarreled. The cases fit real tight on the first firing, but fireformed formed to the chamber, and cycled fine after the first firing... and I wore out that barrel the following year.

On the third barrel, the cases were too tight, so I used the FL die for the first time, and carefully adjusted the die so the cases would just get into the chamber with some effort.

I went through two more barrels, and after the 5th barrel, I was plain tired of the 22-250 (EVERYBODY had one). I was shooting my .220 Swift more and lovin' it. So I and rebarreled up to .244 Rem in 2009-ish.

I packed up the dies (by now, they were all Redding Comp's), and decided to toss the brass, cuz I was never going to own another 22-250 (HA!!)

I sliced two of the cases and there was no sign of incipient head separation. The cases had ~45 firing on each one.

Now that Forster has the "Bump" die, there is no need for a full die, unless you are bringing over fired cases from another chamber.

(A side note - I now own TWO 22-250s, and shoot Lapua cases).

2 - Jim Hull's comment about rat poopie and violin cases is real cutsie pie, but it is meaningless.

The world record benchrest shooter, Jack Neary (BR Hall of Fame), who currently holds almost every world record, does the following.

First, he oils the case body on the first firing, so the case body does NOT grip the chamber walls. On firing, the whole case slides back to the bolt face and "fireforms" to the chamber.
Once formed, he adjusts the sizing die, so the case is slightly longer than the chamber - id est, with the firing pin removed, the bold handle will drop down only half way on a "sized" case, and must be pushed down the rest of the way.

Jack's cases fit the chamber with NO space.

This is loading with "Crush", and it prevents (or minimizes) the case from growing when fired... because ANY space in the chamber when the cartridges is fired dry, will cause the case to stretch. So if you are "bumping 2 thou" when sizing, then you are stretching 2 thou every time you fire the case.

 

[jrock]

I used the Lee collet neck sizing dies on my belted magnums. I would have to FL size after every other shot though as the bottom of the case expanded too much to fit in the chamber. I would check every case for a good fit when neck sizing because I don't want to be in a hunting situation and have a case that is a problem to get in.

 

[J E Custom]

BigEdP51...

You say:

"The vast majority of modern bolt actions have a recessed bolt face and the cartridge does "NOT" lay in the bottom of the chamber."

But it should be obvious that the modern bolt action rifle, because of it's spring loaded ejector, pushes the loaded round to the opposite side of the chamber.

This is why the case swelling in front of the web is not uniform around the case, but to one side - it is because the case was not centered. It is not a critical matter, because once the case if fired, the expanded body redefines the axial center, and you can go from there, unless you keep squishing the body back down, and starting all over.

--------------------------------

"Below is from the "Rifleman's Journal" website written by German A. Salazar in response to a question about partial neck sizing using a full length die."


Reloading: Partial Neck Sizing
by German A. Salazar
http://riflemansjournal.blogspot.com/2010/06/reloading-partial-neck-sizing.html

"[...] 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."

I belong to the "rat turd in the violin case" club.

The problem with this comment is... because of brass spring back, there will ALWAYS be ~0.001 clearance between the case body and the chamber with neck sizing - you don't need a FL die for that... and with 99% of "over the counter" FL dies, they will always create more "slop" (not clearance).

I belong to the "Snug as a Bug in a Rug" club.

There are several problems with Kevin Thomas' comments.

1 - "As I said, if done properly, F/L sizing gives you every bit as long of case life as N/S can,, but without all the additional headaches that go hand in hand with neck sizing.

The problem with that comment is this - I reloaded my first cartridge in 1953 (I AM older than dirt). I have been the chief manager of an ammunition company (twice - I left, they shut down, I came back. I left again, and they shut down for good). I owned my own ammunition company for 4 years. I am a NRA certified handloading instructor, and I have been teaching this stuff for a loooooong time. What I have found is this.

If you take 500 everyday handloaders (throw in 100 "accuracy" handloaders too, if you like), you will find maybe 10 to 20 that can properly set up an over the counter FL sizing die. The "PB Bench" kids pay $175 for a "custom" FL die, which is made so it can't be mis-adjusted, so they don't have to know doodley squat.

Maybe one in 500 reloaders has equipment to measure the headspace of cases and chambers, or shoulder growth when setting up a OTC FL die.... and less than one in 100, knows how to detect case stretching.

Head separation is a common aliment, but neck sizing causes none of this. In 1975, I bought a Remington 40-XB rifle in 22-250, a "deeeeelux set of RCBS dies, and 400 Winchester cases.
I burned out the barrel in a 3 week trip to South Dakota, over PD towns... we shot during the day, and we loaded at night. I neck sized. The cases fit snug (with some crush).

I got it rebarreled. The cases fit real tight on the first firing, but fireformed formed to the chamber, and cycled fine after the first firing... and I wore out that barrel the following year.

On the third barrel, the cases were too tight, so I used the FL die for the first time, and carefully adjusted the die so the cases would just get into the chamber with some effort.

I went through two more barrels, and after the 5th barrel, I was plain tired of the 22-250 (EVERYBODY had one). I was shooting my .220 Swift more and lovin' it. So I and rebarreled up to .244 Rem in 2009-ish.

I packed up the dies (by now, they were all Redding Comp's), and decided to toss the brass, cuz I was never going to own another 22-250 (HA!!)

I sliced two of the cases and there was no sign of incipient head separation. The cases had ~45 firing on each one.

Now that Forster has the "Bump" die, there is no need for a full die, unless you are bringing over fired cases from another chamber.

(A side note - I now own TWO 22-250s, and shoot Lapua cases).

2 - Jim Hull's comment about rat poopie and violin cases is real cutsie pie, but it is meaningless.

The world record benchrest shooter, Jack Neary (BR Hall of Fame), who currently holds almost every world record, does the following.

First, he oils the case body on the first firing, so the case body does NOT grip the chamber walls. On firing, the whole case slides back to the bolt face and "fireforms" to the chamber.
Once formed, he adjusts the sizing die, so the case is slightly longer than the chamber - id est, with the firing pin removed, the bold handle will drop down only half way on a "sized" case, and must be pushed down the rest of the way.

Jack's cases fit the chamber with NO space.

This is loading with "Crush", and it prevents (or minimizes) the case from growing when fired... because ANY space in the chamber when the cartridges is fired dry, will cause the case to stretch. So if you are "bumping 2 thou" when sizing, then you are stretching 2 thou every time you fire the case.

+1

Another very good explanation for the original poster.

I am also older than dirt, but I didn't start loading until 1964 and glad to see that there are more that think the same way.

Actually If you think about the trouble we go to accurately align the action with the bolt and to the bore center line prepping the brass to do the same thing
only makes sense. and setting up the dies to load concentric ammo is paramount for accuracy. and having crush fit has always been good for accuracy and brass life.

J E CUSTOM

 

[bigngreen]

Also, Most bench rest shooters don't size there cases at all they tight neck chamber the neck and turn the necks so that the fired case will just hold the bullet, and simply prime and charge the same case over and over for a match


J E CUSTOM

This is no longer true, I don't know anyone shooting tight cases anymore, they are FL sizing every time and running .004-002 neck tension.

 

[Doc88]

This is no longer true, I don't know anyone shooting tight cases anymore, they are FL sizing every time and running .004-002 neck tension.

Why is it no longer true? What has changed? Not trying to stir the pot just curious why the trend has changed. Thanks for everyone's replies.

 

[Doc88]

Why is it no longer true? What has changed? Not trying to stir the pot just curious why the trend has changed. Thanks for everyone's replies.

I mean I can understand the neck sizing only theory for accuracy more than the FL sizing theory except for guaranteed round feeding. It does make since that a "crush" fit round would be more concentric in the chamber. Educate me please. Thanks.

 

[CatShooter]

Why is it no longer true? What has changed? Not trying to stir the pot just curious why the trend has changed. Thanks for everyone's replies.

When benchrest shooting was mainly group shooting, tight necks were the "in vogue" style of doing it, and cases were a tight fit in the chamber.

When benchrest changed to score shooting, everything changed.

Necks got larger and guys started FL sizing - because speed loading was important, and the chance of a bullet sticking in the throat was now a big problem... it is now, all about speed.
Go to a current bench match, and you can see guys shooting their whole 5 shots in maybe 18 to 20 seconds.

To win a score match (50 - 5X), you can do it with a rifle that holds about ~0.31" group - but in group shooting, a 0.31" rifle would get you laughed out of town... a good group rifle will shoot in the low 1's.

 

[bigngreen]

Most of the guys I know are shooting for group not score though more are starting to try to put that group on the x, they are seeing more consistency in smaller groups, ya you can run fast but that's part of shooting small at 1000 if you can stay on one condition with a gun that tracks. I'm just learning from these guys and shoot a little but it's was shocking how loose they ran their stuff, a buddy of mine is building rifles that are shooting records every year and none of his reamers are tight!
Close range BR is completely different than 1000 yard, the 1000 yard a lot more comes into play that we see as hunters.

 

[CatShooter]

Most of the guys I know are shooting for group not score though more are starting to try to put that group on the x, they are seeing more consistency in smaller groups, ya you can run fast but that's part of shooting small at 1000 if you can stay on one condition with a gun that tracks. I'm just learning from these guys and shoot a little but it's was shocking how loose they ran their stuff, a buddy of mine is building rifles that are shooting records every year and none of his reamers are tight!
Close range BR is completely different than 1000 yard, the 1000 yard a lot more comes into play that we see as hunters.

Here is a video of a close range bench match - at the end of the string, the shooter is firing every 2 to 3 seconds. That's spray and pray where I come from.

https://www.youtube.com/watch?v=GCMxPBsmr6k

 

[bigedp51]

This is no longer true, I don't know anyone shooting tight cases anymore, they are FL sizing every time and running .004-002 neck tension.

bigngreen

I'm very glad that there is someone here almost as smart, good looking and modest as I am.

Also I did not just post my opinion, I posted the comments of the competitive shooters Kevin Thomas and German Salazar. Also Kevin Thomas worked in the Sierra Bullets ballistic test laboratory and fired tens of thousands of test rounds and now shoots for "Team Lapua USA'. And German Salazar had a very good website "The Rifleman's Journal" with many articles on improving your accuracy.

Signed
bigedp51
Spreading rat turds in every violin case I can find.

The above book is dedicated to my buddy CatShooter....who has only made two mistakes in his life...neck sizing only and lubing his cases.

[ame]https://youtu.be/rhZqn2_hTzQ[/ame]