Neck tension, neck turning, bushing dies, etc

[subsonic]

A while back I bought a Redding type S bushing sizer die for my .308 when I was trying to shoot bugholes with it with j-words.

I also had a plain-jane Lee Pacesetter die set and a Forster Ultra seater.

After playing around, not a lot, but enough to know, I found the regular old Lee sizer die was giving me better groups than the Redding!

Why?

I have since come to the theory that if you aren't turning necks, you probably don't need bushing neck dies - and bushings cost as much as a whole sizer die, often times as much as a whole die set, so experimenting with different neck bushings is an expensive proposition.

Now I'm preparing to try cast in this rifle. I'm not really wanting to turn necks, just as I wasn't really wanting to with jacketed, but I think maybe a neck turner is a cheaper alternative to a bunch of neck bushings for different brass.

Just kind-of thinking out-loud to anyone who has more experience than me with this stuff hoping for comments - good or bad.

[smilie=s:

[dagger dog]

An opinion, if the rifle you are shooting has a custom reamed minimum spec chamber, you may have to turn your necks to be able to chamber the new brass.

All SAAMI spec off the shelf rifles will most likley see no measured difference in group size from neck turning unless you have some poorly manufactured brass to start.

Neck sizing only may help the "stock" rifle, bullet to case runout seems to be the most over looked culprit.

I have a factory"target" rifle it happens to be a 308 Win, I shot my smallest to date 5 shot group while fire forming "new brass" to my chamber. ??????

I have and use an RCBS competition micrometer seater but use a Lee Collet sizer, I did turn the necks of my brass at one time (sold it) with a Forster hand held unit, but turning did not improve my shooting.

Your milage may vary !

[Doc Highwall]

How much neck tension are you using? I use the Redding bushing dies whenever I can. Different lots of brass even of the same make will have different case neck thickness's.

[1hole]

"I found the regular old Lee sizer die was giving me better groups than the Redding! Why?"

Well, as a guess, maybe the costly bushing dies really aren't as great as many of their owners seem to be certain of? And maybe Lee's are much better than many of the same people are also certain of! Few seem to understand why it works but Lee's long cylindrical expander is probably the best bottle neck case design available to leave necks straighter than is common with button/ball expanders.

Part of why Lee's simple seaters are usually quite good is that the bullet guide portion tends to be very close to normal bullet diameter so bullets can get started straighter than in more loosely bored dies. That snugness can be a "problem" with oversized cast bullets but, IMHO, and in spite of its current popularity, there's no valid reason for properly cast and lubed bullets to be sized large to start with.

Few people understand that after about 1 thou of 'neck tension' the smaller the necks get the worse the loaded runout will be without any effect at all on the real mechanical grip on bullets.

[FUBAR 6]

Better groups? Or just as good?

There should be no reason the bushing die would introduce problems, given all other things remain the same.

[Moondawg]

99 % of BR shooters use bushing neck dies, and the majority of them have anywhere from 3 to a dozen different sized bushings in .001 increments. If you are going to use bushing dies you should also at least lightly turn your necks so that they are the same thickness. This will require a case neck micrometer to measure them. I don't know where people get this idea that consistent tiny groups and extreme rifle accuracy is cheap, or can be done on a budget because it can't. If you want real consistent accuracy you better be prepared to spend some money on practice, equipment, components and load development. Among other things you need to start is a decent set of 4-5 wind flags.

[FUBAR 6]

"Few people understand that after about 1 thou of 'neck tension' the smaller the necks get the worse the loaded runout will be without any effect at all on the real mechanical grip on bullets.

I don't understand it because I do not have an increase in concentricity issues as I increase neck tension...

With my Benchrest and F class rifles I use .002 and .003 of neck tension and that's after the normal brass "rebound".

[MT Chambers]

On most rifles, careful case prep. will pay off with better groups if the gun is capable of such accuracy, try diff. size bushings, turn case necks for uniformity, use an "in-line bullet seater" for best accuracy. There are no work arounds here, except maybe breach seating.

[subsonic]

How much neck tension are you using? I use the Redding bushing dies whenever I can. Different lots of brass even of the same make will have different case neck thickness's.

Depending on each piece of brass, something like .001 to .002 tension. The lee die sized the snot out of the brass and then yanked it back over the expander button. I used a .337" bushing in the Redding. The largest pin gauge that would start in the neck of the lee die was .331"

[subsonic]

Better groups? Or just as good?

There should be no reason the bushing die would introduce problems, given all other things remain the same.

Better, like .3" on average better for 5 shots. Which makes a rifle that can just about put them all through the same hole, like my 5R Milspec, shoot not that impressively. With the Lee die, just messing around one day I put 7 shots in under half an inch one right after the other without cooling.

[geargnasher]

Lots of talk about tools. No talk about what those tools are doing to affect accuracy with cast boolits. A review of the objectives with basic fit of boolit and case to gun might be in order....

Gear

[subsonic]

Lots of talk about tools. No talk about what those tools are doing to affect accuracy with cast boolits. A review of the objectives with basic fit of boolit and case to gun might be in order....

Gear

I am all ears. Kinda of like your rat! We've had a few and they make surprisingly great pets.

[FUBAR 6]

I just don't believe the Redding die could degrade accuracy--some variable must have changed...

[375RUGER]

Have you checked the runnout of your sized case?

I always lock the size die down with a case in it. This way it locks square to the press.

You can experiment and see the difference in the runout of the sized cases. This will reflect directly on the runnout of the final loaded round.

If I have a die that for whatever reason won't give me decent runnout of the sized neck, I shim it until it does. I have one die that I can think of off hand that is shimmed about .003" on one side. I suspect that it is the lock ring that may not be square. don't know for sure and don't care since the shim works.

I didn't see you mention that you check runnout. If you are are going to be splitting knat hairs you need a concentricity gauge. I sort my .308- anything with more than .002" runout is just practice ammo. I also sort my hunting ammo so that the least runout is reserved for the hunt and the rest is just for practice, although I have greater tolerance for more runout of the hunting ammo-but not much.

[geargnasher]

What's the number-one objective when launching a cast boolit out of the case and into the bore? How do you achieve that? What does neck/body runout or thickness variation have to do with it?

Gear

[375RUGER]

What's the number-one objective when launching a cast boolit out of the case and into the bore? start it straight How do you achieve that? by fitting the boolit to the case, throat, leade so it can only go straight as it is launched

What does neck/body runout or thickness variation have to do with it?See the OP comment below, he started this as a discussion of j-word accuracy. I was addressing this.
J-words do not have the flexibility to custom fit as we can with boolits. They are quite loose in the throat. They are affected by runout. If the case does not fit the chamber and the j-word does not fit the throat/leade then as it is launched it can engrave the rifleing askew. It will still be in the askew when it exits the muzzle which means the rapidly expanding gases will steer the heel of the bullet.

The difference between the boolits and the bullets is that the boolits can and will slump anyway they can and the bullets are more forgiving because they have a condom to prevent slumping.

This can mean the difference in a mediocre rifle or a real head turner. I bought an AR-10T in a pawn shop, it was there on consignment. I was actually there to buy another 7mmRM but walked out with this. This was 10years ago. The rifle showed some promise with boxed ammo. Then I started the search for "the load". On the journey I discovered it shot 155 Palma's well- .110" but the load was HOT. Backing the load off only gave 1/2MOA. I eventually settled on 168 A-maxs over a case full of Varget. The load only shoot in the 3s if the runout is under .002". Groups open up when runout is >.003". I can call a flyer with this rifle if I throw in a .005" runout bullet in a mag with all .001" and I know it's position in the lineup.
I'm sure the guy would have never sold that rifle if he had taken the time to find the load.

What does this have to do with it? Making sure the case is sized so it fits the chamber straight. So the bullet can start it's journey straight.






A while back I bought a Redding type S bushing neck die for my .308 when I was trying to shoot bugholes with it with j-words.

After playing around, not a lot, but enough to know, I found the regular old Lee sizer die was giving me better groups than the Redding!

[smilie=s:


Got to go.

[FUBAR 6]

Very simply he stated that: Lee dies produced better accuracy than Redding bushing dies....

That the equipment question(s)

[375RUGER]

Very simply he stated that: Lee dies produced better accuracy than Redding bushing dies....

That the equipment question(s)

Yes, and I asked if he knew if each die was true.
It may be a case of neck tension difference. But you don't know that for sure. I am merely making a suggestion that it maybe something else. Alignment!! I'm not disputing neck tension and I wouldn't rule it out as the cause of inaccuracy.
I just like to make sure that everything is aligned/fit before I go chasing my tail during load development.

[r1kk1]

Use what you think works best, I just don't buy it. I played with a collet sizer using jacketed in a 30-06. I shot into the 4s for 5 5 shot groups. I sent a couple of cases to Lee and they made me a new spindle turned down and groups averaged into the 3s at 100 yards. Not bad for 190 grain bullets. I use a Wilson and hit high 2s to 3s. Neck tension matters and I believe and my own opinion, that concentricity didn't come into play until you increased distances well past the 300 yard line. Alas this was one near bone stock Savage that I used. The best seaters that I've used are Wilson and Redding.
That is my experience.

Just having fun to see what an near off the shelf factory hunting rifle can do. Factory rifles have shot some impressive groups compared to yesteryear. Brass has come a long ways too. I like Lapua and if they don't make it Norma, then I deal with the rest.

Use what you like. There are so many variables that a few days at the range doesn't offer as much information as a shooting tunnel. Beggs has one in Texas as well as most bullet companies. Beggs did a lot of testing when the Houston warehouse was around.

I just picked up a Vickerman die and a similar one from Ponsness Warren. Both are seaters and something I want to try.

To each his own.

r1kk1

[Lance Boyle]

Immediately apparent the nice thing about bushing dies is they let you easily adjust for our holy cast boolits without squishing them out of desired size.

I've lots of dies and have good luck with jacketed with my oldest ones, RCBS, that squeeze the ever loving piss out of some case necks to 6-8 thousandths under nominal bullet diameter. That's with the factory expander in place not without. Without it's more tight.

[Casting Timmy]

Here would be an interesting trick to try out if you're up to it. Completely size a piece of brass in the Lee set and then lube it up and smoke it and run it thru the Redding die. Of course set both dies up like have you have been. Then size something in the Redding die and then lube and smoke it for the Lee Die. The Lee Die will definitely change the neck making it bigger and smaller automatically, but if you see the sot wiped off the body or not wiped off the body you know which die is sizing the case smaller or larger.

I don;t think it's the dies directly, it's what the dies produce for you that's different and your rifle/ load prefer the size of the brass out of the Lee dies better.

If your bolt feels different when you close it on your rifle, you would know one isn't sized as much as the other without doing the sizing test.

[gray wolf]

Take some fired cases that you have not done anything to, then check the necks with a concentricity gauge. the necks should be .000 .0005 run out. If not your chamber is off. Fresh out of the barrel is as straight as you will ever get.
Then use your concentricity gauge and check every step in the loading process
And you will see right away at what point your bending the necks.
Some off the shelf brass is bent in the body ( banana brass ) you will never get it straight. As been said, turning necks for a factory chamber is ( most of the time )
a wasted effort. Trimming to just take a skin cut off so there close to the same thickness does help some. The more you take off the looser the fit in the chamber.
If you want to do it right you need a case neck ball mike, concentricity gauge,
and a good neck turner, along with the best brass you can buy,
Norma or Lapua (spelling) Measure a loaded round at the neck, then fire the round and measure the neck again, the difference is the slop in your chamber.
If lets say a 270 Win. round is .308 at the neck when loaded, and .310 when fired
you have a good chamber, but every .001 you remove from the neck by turning
is making your condition worse, .002 is a safe clearance.
If the case neck is .004 .005 bigger after firing you are wasting your time.
Uniform the primer pockets ( not ream) uniform them, and DE-burr the inside of the pocket. It's all or nothing, costly and very time consuming.
Factory rifles and factory chambers can greatly benefit from a Lee collet die if used correctly, you can do very well with the collet die.
Been there and have multiple T-shirts.
Messing with case necks is a VERY small part of the accuracy equation.
It will give you even release of the bullet, and let the bullet exit straight.

[FUBAR 6]

^^^^Very good post, that's a lot of info on brass prep--are you a Benchrest shooter?

[geargnasher]

If the case neck is .004 .005 bigger after firing you are wasting your time.


YES. And most modern bottleneck rifle cartridges are set up this way, because the gun makers fudge on the MAX chamber spec, and the brass makers fudge on the MINIMUM thickness spec because they're skeered somebody's going to find that unfortunate combo that pinches a condom bullet and makes the pressure go through the roof.

Since GW used the .270 as one example, I'll follow. I have two .270s, and both have .3105" chamber necks at the front, about .312 at the base of the neck. The fattest boolit that will fit either throat entrance is right at .279". The thickest uniform brass I can find is .013" at the neck after truing. Loaded, that's .305", leaving as much as .007" slop. Above 1600 fps both rifles shoot PATTERNS. I have some tricks to reduce the chamber clearance and at least the one rifle shows a dramatic increase in accuracy at higher velocities merely by solving that issue.

Accurate, high-velocity cast boolit shooting requires a clearance a lot different from the .002" quoted, though.

Gear

[Doc Highwall]

here is a great site for information. You can get lost in this one.

http://www.6mmbr.com/index.html

[felix]

Also, it depends on how much the boolit dynamically expands. The magic clearance for the bench gun up stairs using mainline boolit load is 0.0008 total. It took quite a few rounds to narrow this dimension to this value, The hardest selection was the powder speed with the boolit set at a fixed accuracy and speed as chosen up front. ... felix

[HangFireW8]

A while back I bought a Redding type S bushing sizer die for my .308 when I was trying to shoot bugholes with it with j-words.

I also had a plain-jane Lee Pacesetter die set and a Forster Ultra seater.

After playing around, not a lot, but enough to know, I found the regular old Lee sizer die was giving me better groups than the Redding!

Why?


There are two reasons I can think of, off the cuff. One has already been identified by 375RUGER:


Have you checked the runnout of your sized case?

The reason concentric loads are important is hinted at by gearnasher:


What's the number-one objective when launching a cast boolit out of the case and into the bore? How do you achieve that? What does neck/body runout or thickness variation have to do with it?

So, we want to start are boolits out right, right down the middle of the throat, not some cocked off to one side and some off to another.

The second reason (also hinted at by Gear) has to do with neck tension. If some j-words release with 5 pounds of force and others with 60 pounds (extremes here), it will really show up in your groups. Since cast reloaders are often more careful with neck tension, because we want to avoid swaging are boolits, we sometimes forget that consistant tension is not a given, and it is still important for accuracy reasons beyond swaging.

HF

[geargnasher]

Consistent neck tension is critical to the way the pressure curve behaves from the get-go, and that initial pressure build is what establishes the barrel vibrations that affect the direction the boolit flings when it leaves the muzzle. If you want it to fling the same way every time, you must be able to repeat the same pressure/time curve in the barrel each shot.

Developing a "feel" for neck expander resistance and boolit seating pressure and sorting groups of cartridges by this will improve things greatly.

Gear

[FUBAR 6]

Took a lot of research, reading, trial & error and time for me to learn/put into practice, the things Grey Wolf outlined in his post.

I knew how to do basic handloading/reloading as a teenager, but when I jumped head-first into Benchrest rifles, I was forced to learn, what i will term "precision handloading".

Now that's me, some of you learned this stuff just because it's part of being a good student of the technical/practical process.

When possible, for the weapon type, I will use my K&M arbor press with the gauge for seating, but as Gear said, I know the "feel of good vs bad seating" on my Hollywood press.