Neck Sizing Problems

[JFrank]

First video that popped up.

With all the other threads by the OP on neck sizing, OAL, not trimming different brass I got nothing else

Lol I’m about out too’ last one is the guy on the video us sizing the neck down .008 ish E gads’ if that doesn’t work a piece of brass nothing will ..

 

[243winxb]

I bought a Lee Collet Neck die for my 243 about a year of 2 ago. Had to test it after all the years. Followed Lee instruction, while measuring. Lee claims 25 pound on the lever will neck size the brass. NOT.
I found it takes 40 lbs. I kept adding weight to the handle till it got done right.
Loaded 20 rounds, test fired. Sold it. No improvement in accuracy over a bushing die with *Rem 600 Mohawk carbine*. Edit to correct gun.

Bushing die a lot less work.

 

[westernrover]

If you're already using a Lee Collet Die and getting inconsistent neck ID, then it's probably a matter of lock-ring adjustment. You might need to screw the die farther down and use more force on the press handle.

If you have a press without cam-over, then the LCD should be screwed 1 to 1.25 turns past contact with the shell plate.
If you have a press with cam-over, you need to screw the LCD down far enough that it will not cam-over -- at least 2 turns past shell plate contact.

If in doubt, screw the die in farther. You can only go wrong by not screwing it in far enough.

 

[westernrover]

Everyone has their opinions in reloading. The Lee Collet Die will do a fine job on sizing necks if used correctly. It won't please everyone, and the results won't miraculously beat cases that are properly prepared by some other method. There are a lot of ways to accomplish the same thing and the just the method with which we achieve a suitable neck diameter can hardly be expected to dramatically shrink group size.

There is a lot of criticism of neck-only sizing and advocacy for full-length sizing, but I have not seen a valid criticism of neck-sizing as a step separate from body sizing. I neck size all my rifle brass, and that does not mean I do not also full-length size the body and bump the shoulder. I use a Redding body die, but a full-length sizing die works fine too. The full-length sizing die only offers a single neck size though. If it happens to be what you want, enjoy. The collet neck die can get the neck ID to match the mandrel OD which can be selected for a suitable neck tension. Neck bushing dies and bushings or mandrel dies and mandrels offer other ways to customize the neck OD or ID. I've personally found bushing dies and trying to achieve a certain neck ID by sizing to an OD using a bushing to be frustrating. Redding admits that if the neck is sized down too far by a single bushing, the resulting neck OD will be smaller than the bushing -- this is not spring-back, but spring-in. It's bizarre and frustrating. Redding's published solution is to size down in steps with multiple bushings. The collet die, on the other hand, uses collet fingers to press the neck against the mandrel. Provided sufficient force (through the press handle) is used, the neck will be formed around the mandrel and will not spring-in to a smaller diameter the way bushing dies will. Some bushing die users will say "mine doesn't do that" and that's fine, but Redding publishes the fact that some do. Using mandrel dies like Sinclair's is also a two-step process where the neck must be sized smaller than the mandrel, and then the mandrel pushed in to open it up. I have no personal experience with these mandrels, but they look like a good method.

 

[Walkalong]

The Lee Collet Die will do a fine job on sizing necks if used correctly.

They can, until the neck sizing, by any means, catches up with you. I went through the neck sizing is better phase about 40 years ago, Lee collet style neck sizer, Lee "Dead Length" seater, and my .222 Mag shot great that way, but as we all do, it ended up with cases not wanting to chamber, loose neck tension etc. Cured all of that with a full length sizer and annealing with a torch with cases standing in water, later on went to bushing style FL sizers. No loss of case life, no chambering issues, great accuracy, as good or better than neck sizing, just moved on, as many, many others have from neck sizing.

 

[Kaldor]

Everyone has their opinions in reloading. The Lee Collet Die will do a fine job on sizing necks if used correctly. It won't please everyone, and the results won't miraculously beat cases that are properly prepared by some other method. There are a lot of ways to accomplish the same thing and the just the method with which we achieve a suitable neck diameter can hardly be expected to dramatically shrink group size.

There is a lot of criticism of neck-only sizing and advocacy for full-length sizing, but I have not seen a valid criticism of neck-sizing as a step separate from body sizing. I neck size all my rifle brass, and that does not mean I do not also full-length size the body and bump the shoulder. I use a Redding body die, but a full-length sizing die works fine too. The full-length sizing die only offers a single neck size though. If it happens to be what you want, enjoy. The collet neck die can get the neck ID to match the mandrel OD which can be selected for a suitable neck tension. Neck bushing dies and bushings or mandrel dies and mandrels offer other ways to customize the neck OD or ID. I've personally found bushing dies and trying to achieve a certain neck ID by sizing to an OD using a bushing to be frustrating. Redding admits that if the neck is sized down too far by a single bushing, the resulting neck OD will be smaller than the bushing -- this is not spring-back, but spring-in. It's bizarre and frustrating. Redding's published solution is to size down in steps with multiple bushings. The collet die, on the other hand, uses collet fingers to press the neck against the mandrel. Provided sufficient force (through the press handle) is used, the neck will be formed around the mandrel and will not spring-in to a smaller diameter the way bushing dies will. Some bushing die users will say "mine doesn't do that" and that's fine, but Redding publishes the fact that some do. Using mandrel dies like Sinclair's is also a two-step process where the neck must be sized smaller than the mandrel, and then the mandrel pushed in to open it up. I have no personal experience with these mandrels, but they look like a good method.

If you havent tried mandrels, I suggest you give it a shot. The steel Sinclair mandrels are really affordable and work quite well. Personally I have steel, and TiN coated, and havent seen a need for the carbide version.

My biggest issue with neck sizing with the Lee die or a specific bushing is that you are at the mercy of whatever your case neck is for thickness. If its a hair thicker on one side, that will be imparted into your case. The beauty of a mandrel is that it doesnt care if your brass isnt a perfect thickness, and simply puts the hole in the center. Granted if it is really off, well then you have a problem that nothing besides neck turning can fix. The mandrel just makes for much more consistent runout the vast majority of the time, which in turn creates more accurate ammo. I anneal every firing to bring the brass back to a uniform hardness, full length size without the expander ball in, and the set neck inside diameter with mandrels from Sinclair. The Sinclair mandrels work well enough, and give you 2 thou neck tension, which is what I want. If you want to get real picky, 21st Century sells a really nice set that allow you be pretty much whatever diameter you want to be.

 

[westernrover]

They can, until the neck sizing, by any means, catches up with you. I went through the neck sizing is better phase about 40 years ago, Lee collet style neck sizer, Lee "Dead Length" seater, and my .222 Mag shot great that way, but as we all do, it ended up with cases not wanting to chamber, loose neck tension etc. Cured all of that with a full length sizer and annealing with a torch with cases standing in water, later on went to bushing style FL sizers. No loss of case life, no chambering issues, great accuracy, as good or better than neck sizing, just moved on, as many, many others have from neck sizing.

Why not just add a body die? There's nothing about neck sizing that prohibits the body from being sized and shoulder bumped so that not only is chambering assured, but internal case volume will also be consistent.

 

[westernrover]

...My biggest issue with neck sizing with the Lee die or a specific bushing is that you are at the mercy of whatever your case neck is for thickness. If its a hair thicker on one side, that will be imparted into your case. The beauty of a mandrel is that it doesnt care if your brass isnt a perfect thickness, and simply puts the hole in the center. .....

I hope to try the Sinclair mandrels, perhaps for the next cartridge I buy a set of dies for.

The Lee collet die is also a mandrel die. It does not use bushings and it works by sizing the ID not the OD. The spring collet squeezes the brass around the mandrel, and so it is indifferent to case neck thickness or variations in it.

One difference with a mandrel-only die like the Sinclair is that the neck has to be sized-down first by some other means like a standard sizing die without the expander ball. Another difference is that there are a variety of mandrel diameters available rather than cartridge-specific mandrels. The other difference I can think of is the separate mandrels can be used for neck-turning, whereas the Lee collet's mandrel is not intended for that.

 

[lightman]

I have not replied to this thread yet because I have never used a Lee Collet die. The only neck sizing that I do is for my tight neck chambers that I have to neck turn the brass for. I use either Redding or Wilson bushing dies for those. Lots of shooters swear by the Lee die, I just have never used it.

 

[Walkalong]

Why not just add a body die? There's nothing about neck sizing that prohibits the body from being sized and shoulder bumped so that not only is chambering assured, but internal case volume will also be consistent.

Why not a bushing style FL sizer instead?

 

[westernrover]

The main reason not to use bushing dies is to avoid the expense of dozens of bushings costing many hundreds or thousands of dollars. The TiN bushings can be over $30 a piece and it's not unusual to end up with a half-dozen for a given cartridge. There is no more expensive way to size cartridge brass.

One of the reasons so many bushings are often needed to size this way is because the brass often does not take the diameter of the bushings. According to Redding, "It has come to our attention through customer calls and our own use of the bushing style sizing dies that in certain instances, a given neck sizing bushing will produce a case neck diameter that can be several thousandths of an inch smaller than the actual diameter of the bushing. This idiosyncrasy occurs when the neck diameter of the fired case is a great deal larger than the diameter of the neck sizing bushing, such as occurs when factory chambers are on the large side of the tolerance range and the brass is on the thin side. Typically, we have not noticed
any problems until the case neck is reduced more than 0.008-0.010”. Solutions include, increasing bushing diameter to compensate and/or the use of a size button. Reducing the neck diameter in two smaller steps by using an intermediate diameter bushing will also help. More concentric necks will also result using this method, as the case necks are stressed less during sizing."

Another reason not to use bushing dies is that the bushing sizes the outside diameter of the neck. Therefore it does not assure the roundness or the concentricity of the inside diameter which is what actually holds the bullet. An expander ball may or may not be used with a bushing die, but if the bushing is large enough, the ball may do nothing, and if the bushing is small enough, the ball will undo what the bushing has done. The bushing alone, however, will only form the outside diameter of the neck, and unless the neck has also been turned, the inside diameter will probably grip the bullet with inconsistent tension unless an expander is used.

I am a member of the Redding Type S Bushing Die club. I have the requisite collection of bushings, as well as an upgraded carbide expander ball for some sizes. The collet and mandrel do the same thing for a fraction of the cost and complexity. A Redding body die very inexpensively takes care of what the collet die does not.

 

[Walkalong]

The main reason not to use bushing dies is to avoid the expense of dozens of bushings costing many hundreds or thousands of dollars. The TiN bushings can be over $30 a piece and it's not unusual to end up with a half-dozen for a given cartridge. There is no more expensive way to size cartridge brass.

One of the reasons so many bushings are often needed to size this way is because the brass often does not take the diameter of the bushings. According to Redding, "It has come to our attention through customer calls and our own use of the bushing style sizing dies that in certain instances, a given neck sizing bushing will produce a case neck diameter that can be several thousandths of an inch smaller than the actual diameter of the bushing. This idiosyncrasy occurs when the neck diameter of the fired case is a great deal larger than the diameter of the neck sizing bushing, such as occurs when factory chambers are on the large side of the tolerance range and the brass is on the thin side. Typically, we have not noticed
any problems until the case neck is reduced more than 0.008-0.010”. Solutions include, increasing bushing diameter to compensate and/or the use of a size button. Reducing the neck diameter in two smaller steps by using an intermediate diameter bushing will also help. More concentric necks will also result using this method, as the case necks are stressed less during sizing."

Another reason not to use bushing dies is that the bushing sizes the outside diameter of the neck. Therefore it does not assure the roundness or the concentricity of the inside diameter which is what actually holds the bullet. An expander ball may or may not be used with a bushing die, but if the bushing is large enough, the ball may do nothing, and if the bushing is small enough, the ball will undo what the bushing has done. The bushing alone, however, will only form the outside diameter of the neck, and unless the neck has also been turned, the inside diameter will probably grip the bullet with inconsistent tension unless an expander is used.

I am a member of the Redding Type S Bushing Die club. I have the requisite collection of bushings, as well as an upgraded carbide expander ball for some sizes. The collet and mandrel do the same thing for a fraction of the cost and complexity. A Redding body die very inexpensively takes care of what the collet die does not.

Somewhat of an exaggeration. Some folks used to neck size and use a body die when needed, some may still do it that way, but it is not as consistent as using a FL bushing die or honed FL die every time. I use mandrels after the bushing die on a couple of calibers. Yes, bushing dies can be problematic with large sloppy chambers where the neck has to be sized a great deal. In that case why are we even worried about accuracy type loading for a sloppy chamber. Meh. Bushing style dies, neck or FL aren’t the answer for everything.

The Lee collet sizer works well until you have chambering issues, just like any neck sizing.

The Lee dead length seater (do they still make it?) does a great job.

Id rather have a sizing routine that works all the time and is consistent. If you have to use a body die sometimes, or FL size sometimes because you’re neck sizing, to me that’s not consistent.

YMMV

 

[JFrank]

Why not a bushing style FL sizer instead?

Exactly’
I can’t imagine taking all that neck and body die stuff and mandrels etc. on the road with me to a hotel room when I can just run them one time through a good bushing die and be done. Maybe us old Benchrest guys aren’t as dumb as we look. Lol

I spend about 15 bucks on a bushing that lasts a lifetime

 

[JFrank]

The main reason not to use bushing dies is to avoid the expense of dozens of bushings costing many hundreds or thousands of dollars. The TiN bushings can be over $30 a piece and it's not unusual to end up with a half-dozen for a given cartridge. There is no more expensive way to size cartridge brass.

One of the reasons so many bushings are often needed to size this way is because the brass often does not take the diameter of the bushings. According to Redding, "It has come to our attention through customer calls and our own use of the bushing style sizing dies that in certain instances, a given neck sizing bushing will produce a case neck diameter that can be several thousandths of an inch smaller than the actual diameter of the bushing. This idiosyncrasy occurs when the neck diameter of the fired case is a great deal larger than the diameter of the neck sizing bushing, such as occurs when factory chambers are on the large side of the tolerance range and the brass is on the thin side. Typically, we have not noticed
any problems until the case neck is reduced more than 0.008-0.010”. Solutions include, increasing bushing diameter to compensate and/or the use of a size button. Reducing the neck diameter in two smaller steps by using an intermediate diameter bushing will also help. More concentric necks will also result using this method, as the case necks are stressed less during sizing."

Another reason not to use bushing dies is that the bushing sizes the outside diameter of the neck. Therefore it does not assure the roundness or the concentricity of the inside diameter which is what actually holds the bullet. An expander ball may or may not be used with a bushing die, but if the bushing is large enough, the ball may do nothing, and if the bushing is small enough, the ball will undo what the bushing has done. The bushing alone, however, will only form the outside diameter of the neck, and unless the neck has also been turned, the inside diameter will probably grip the bullet with inconsistent tension unless an expander is used.

I am a member of the Redding Type S Bushing Die club. I have the requisite collection of bushings, as well as an upgraded carbide expander ball for some sizes. The collet and mandrel do the same thing for a fraction of the cost and complexity. A Redding body die very inexpensively takes care of what the collet die does not.

In long range Benchrest (1000 yards) we shoot arguably the smallest groups in the world, we could not do that using poor technics , poor brass prep. I do not know of one single competitor that subscribes to the information in your post.

 

[Kaldor]

I hope to try the Sinclair mandrels, perhaps for the next cartridge I buy a set of dies for.

The Lee collet die is also a mandrel die. It does not use bushings and it works by sizing the ID not the OD. The spring collet squeezes the brass around the mandrel, and so it is indifferent to case neck thickness or variations in it.

One difference with a mandrel-only die like the Sinclair is that the neck has to be sized-down first by some other means like a standard sizing die without the expander ball. Another difference is that there are a variety of mandrel diameters available rather than cartridge-specific mandrels. The other difference I can think of is the separate mandrels can be used for neck-turning, whereas the Lee collet's mandrel is not intended for that.

I understand how the collet die works. The beauty of the Sinclair mandrel is that you just buy the body, and the mandrels are like $20 per caliber. Yes, I double pass, FL sizer (no ball) and then mandrel. Its an extra step, but I feel that one extra step, in combination with FL sizing produces superior ammo. I also get alot less cases stretching because you arent dragging the expander ball back thru the brass, which stretches the brass length slightly, and work hardens it even more. How do I know it stretches less? I can see it when I trim. The pieces sized with a mandrel I have to trim less than those sized with a ball.

I guess Im not a fan of the Lee die because its only for sizing the necks. Neck sizing doesnt really provide any real tangible benefits in the long run other than ease. It doesnt extended brass life, because brass still stretches every firing. When that brass stretches, it becomes worked hardened, regardless if you are only sizing the neck which is the most fragile part of a case. And you still have to FL body size the brass every few firings depending on your rifle. The minimal work we do when sizing is minor compared to the abuse it takes when its fired, so the "neck sizing increases brass life" mantra is a crock. When you have to full size a neck sized case every 4 firing because the case is blown out and you can barely close the bolt, do you think that sizing that brass imparts more or less stress into the brass than the minimal pass required doing a FL sizing every firing? Its much akin to resizing brass that came out of MG vs brass that came out of a bolt gun.

My other complaint about neck sizing is that while your brass may be fired formed perfectly to your chamber, which is a good thing, you still have a tolerance stack up in the action, bolt and barrel which does exacerbate concentricity issues. A thou here, a thou there, thats tolerance stackup, and its something that every rifle has at some level. Custom rifles made by a skilled smith with quality actions and barrels have less issues, but factory guns can be awful. The chamber might be just slightly out of round, or off center, or canted just slightly. Let me explain how that affects the entire thing. I look at neck sizing like a clock with how brass is indexed coming out of the chamber. The brass is fired, and now its the same as your chamber, and we will call that 12 o'clock. So this brass, that is perfectly fire formed to your chamber, was clocked at 12 o'clock when fire formed. You process, neck only, and now that brass gets loaded. How can you guarantee that you get the reloaded round back into the chamber at 12 o'clock? Its almost impossible and that is where the tolerance stack comes back to bite you. If it comes back into the chamber at 6 o'clock its going to be way off where it should ideally because the brass is not perfectly concentric to the bullet in relation to the bore. Now you take a round that is FL sized with a 2 thou shoulder bump. That brass is consistently the same size, shot after shot after shot. It doesnt care where it is clocked because the brass is always concentric and can be indexed in any position in the chamber. The brass being concentric to the bullet, puts the bullet in the same location every firing in relation to the bore. I would rather have a result that is absolutely consistent and consistency with high levels of detail always averages out better than something that can be inconsistent even with high levels of detail.

You look at every "pro" shooter, and I use that term loosely as there are very few people out there that are 100% full ride shooters, but they win and sometimes they even win money. You look at what they are doing. Are they neck sizing? No. There might be a few out there that are doing it, but they are few and far between.

 

[AJC1]

Every discipline has a process that works for them or is the standard. It seems as though some people try and grab a solution out of a process that is nothing like what their doing, only after they have a problem or their process is not meeting their goals. The why in the brass processing procedure is important. The process of neck sizing was found to be problematic for long term. The primary selling point was brass life and accuracy. Accuracy is consistency and the case is never stable over time by neck sizing.

 

[gwpercle]

As you shoot and trim the brass it gets thinner in the neck area ... you have mixed brass and some makes just thin out sooner than others . Three reloadings in rifle with normal sized factory chamber and this is about when the thin necks start showing themselves . 5 to at most 8 reloadings with a standard factory chambered barrel is what I get ... I use a Neck Sizing Die that takes different sized bushings and can easily make the neck size smaller . Redding Type S Neck Sizing Bushing Die with a set of Neck Sizing Bushings .
These will let you size the too large necks down and get a few more loadings out of the cases .
Gary

 

[westernrover]

Somewhat of an exaggeration. Some folks used to neck size and use a body die when needed, some may still do it that way, but it is not as consistent as using a FL bushing die or honed FL die every time.

Sizing inconsistently is a sure way to get inconsistent results, but there there is no proposition to do so here. The body die being needed every time is not an argument against neck sizing. We have to decap every time too, but that has no bearing on neck sizing. Though I will point out that the Lee Collet die's decapping pin is not removable. That makes it undesireable for sizing necks once brass is primed -- not a typical workflow, but one that's possible when re-working. I suppose the pin could be cut off the mandrel, but it is what it is.

...Yes, bushing dies can be problematic with large sloppy chambers where the neck has to be sized a great deal. In that case why are we even worried about accuracy type loading for a sloppy chamber.

I don't agree that large sloppy chambers are necessary pre-requisites for sizing necks down by eight thou or more. Many SAAMI spec chambers are more than 8 thou over. Instead, I would argue that bushing dies are really best suited for tight chambers made with a custom reamer. Factory chambers are more likely to work poorly with a bushing die and a single bushing than they will with a collection of bushings.

Id rather have a sizing routine that works all the time and is consistent. If you have to use a body die sometimes, or FL size sometimes because you’re neck sizing, to me that’s not consistent.

YMMV

Definitely use the body die every single time. Anything else is by definition inconsistent. Don't malign neck-sizing as inconsistent when it is not. You just sound like you don't know what you're talking about. I know it's popular with Bench Rest shooters like Eric Cortina to trash talk neck sizing. They never mention body dies and consistently talk like full-length and neck-only are the two and only two ways to size brass. It's just a bunch of hot air. Few people can afford to outshoot them, so the rhetoric they put around their opinions gets prominence, but it doesn't mean they know what they're talking about or that they aren't being disingenuous and facetious in their baited rhetoric.

 

[westernrover]

I ...You look at what they are doing. Are they neck sizing? No. There might be a few out there that are doing it, but they are few and far between.

I don't know anyone who does not size their necks. If they're not sizing their necks, they are not likely to have the right neck tension or even bullet retention.

Explain what the benefit is of sizing the neck in the same die as the body versus sizing them in different dies? It's convenient, but that is not everyone's goal. Any other advantage? The advantage I claim for using separate dies is there are more options. I have more options about which kind of die to use for each process, and I have more options about how to adjust the dies. Is there a disadvantage to using separate dies? Possibly cost, but some full-length sizer setups are more expensive than separate dies, so there's nothing conclusive there. Anything else?

If you ask competitive shooters, I am sure you will hear them explain that they use multiple dies for sizing their brass -- almost every one of them. Is the LCD popular in bench rest? I doubt it. They don't use factory chambers either. But other mandrels are popular and those mandrel dies like Sinclair, KMS, and Wilson are NECK SIZING dies.

 

[JFrank]

If I were to use a neck sizing die it would most likely be a Wilson, they are IMO simple and effective with only one down side and that of course is having to sooner or later full length size.
Personally I find that the less I mess the better the rifles shoot, quite frankly one would think the opposite but it’s surprising how few tools a guy really needs.

 

[Kaldor]

I don't know anyone who does not size their necks. If they're not sizing their necks, they are not likely to have the right neck tension or even bullet retention.

Explain what the benefit is of sizing the neck in the same die as the body versus sizing them in different dies? It's convenient, but that is not everyone's goal. Any other advantage? The advantage I claim for using separate dies is there are more options. I have more options about which kind of die to use for each process, and I have more options about how to adjust the dies. Is there a disadvantage to using separate dies? Possibly cost, but some full-length sizer setups are more expensive than separate dies, so there's nothing conclusive there. Anything else?

If you ask competitive shooters, I am sure you will hear them explain that they use multiple dies for sizing their brass -- almost every one of them. Is the LCD popular in bench rest? I doubt it. They don't use factory chambers either. But other mandrels are popular and those mandrel dies like Sinclair, KMS, and Wilson are NECK SIZING dies.

When you FL size you are sizing the necks, which is exactly what I do. Unless of course then you are using a body die, then that really isnt a FL sizer. Most of the cartridges I shoot are just using a standard Hornady FL sizing die with the expander removed. They are simple enough, and I havent seen any real evidence that super high priced dies offer any tangible benefits that can be measured on the target, but I am only a slightly above average shooter that is very conscientious about my reloading practices. I do use a few bushing dies, Redding and Hornady with Short Action Customs bushings, but they are used for sizing wildcats like a 6 Grendel or experimenting with my 6 Creedmoor in conjunction with a mandrel trying to just size/move the neck the absolute minimum and get 2 thou neck tension. Jury is still out on that last one, but the gun is a consistent .350" 5 shot gun, sometimes better, sometimes worse, so who knows. Maybe by the time I wear this barrel out next summer I'll know.

You openly admit that you neck size with a collet die but use a Redding body die, so you are still double passing just like I am. Are you double passing every firing? Or just when the inevitable bolt closing and opening issues rear their head because the case is blown out? If you are only doing body sizing when you have bolt issues, then you are introducing a tolerance stack like what I brought up before. However, if youre body sizing every pass, and then take a trip thru the collet die, then you are in essence doing the same as I am, which depending on the absolute consistency of the necks of the brass, can produce some excellent ammo. I wont dispute the effectiveness of the collet die, as its just a mandrel of a different type. What I do dispute is using the collet die and only doing neck sizing.

The thing about mandrel dies (Sinclair, 21st Cent, KMS, custom made) is that yes, you are technically correct, they are a neck sizing die. However they dont function like a traditional neck sizing operation that is done from the outside of the case. Alot of folks agree that this allows them to produce more concentric ammo as you arent relying on the neck of the brass to be perfectly the same thickness and the issues that can have. Yes, one can trim necks, and Ive gone down that rabbit hole with some Lake City LR 308 brass (skim cut to average out neck thickness issues) but that opens up another set of issues that sometimes needs to be ironed out as well.

The best investment I have made over the years is that on rifles that I expect extreme accuracy from, I buy good brass, and I take care of that brass by annealing, FL sizing the absolute minimum I can on the shoulder bump, and using a mandrel to avoid stretching the brass. I have 308 brass that is in excess of 10 firings with what some might consider to be a generous powder charge using this method, so it must be working.

 

[BJung]

I've owned a custom Lee Neck Sizing Collet die and plan to order a replacement. Using the Lee Collet die, I recorded a slight twitch at most on the Sinclair Concentricity Gauge meter while checking loaded rounds. Trying neck sizing and expanding a case neck using an expander plug, my finished loads measured at the bullet ogive were not concentric at all. The problem with the Lee die is that it is made specific to for a certain neck thickness. When ordeirng a custom die, Lee asks for sample brass and a bullet. So, I tried sizing reformed brass (30-06 to 7.7x58) and the neck was too thick and got stuck in the die. I damaged the die trying to remove the madrel from the case. So, the rule is, is to turn the necks on the reformed brass.