Bushing dies
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There's two sides to this: you can neck size only, or you can neck size with what the truly anal retentive crowd refers to as a shoulder bump-to avoid something called "the doughnut" at the base of the neck.
Making this as simple as possible, if you're trying to minimize any/all variables with your ammunition, you will:
Weigh brass and keep lots segregated by weight. How small your allowed deviations are is up to you. You're trying to create the same case volume.
You will drill your flash holes to a uniform diameter, deburr the hole and make sure the primer pockets are a uniform depth. All in the name of more uniform primer flash, ignition.
You will trim brass overall length, then turn the case walls to uniform thickness +/- a couple ten thousandths of an inch.
Now, here's where the bushing comes in. By using differently sized bushings (and possibly futzing with case wall thickness), one can adjust the neck tension on your bullet to produce a more uniform release of the bullet.
All this work is an attempt to reduce group size. There's a website called Benchrest Central where you can learn more about such fascinating uses for your free time. I hung out there for awhile some years back. One of the things I learned, was that despite all the work described above, some top competitors discovered that a slight crimp produced a more uniform powder burn and bullet release in their tests/matches.
BTW, SFAIK, all this is intended ONLY for use in bolt guns, loaded one round at a time. There's no way in heck any bullets so seated are likely to survive the feed cycle of an Mforgery. Some folks might be able to manage to work the process for firearms with manually operated bolts.
The only thing I bother to do for match loads or a couple of specialty bullets is to use an M die to uniform the neck tension and slightly flare the case mouth to help bullet alignment with the case neck.
Making this as simple as possible, if you're trying to minimize any/all variables with your ammunition, you will:
Weigh brass and keep lots segregated by weight. How small your allowed deviations are is up to you. You're trying to create the same case volume.
You will drill your flash holes to a uniform diameter, deburr the hole and make sure the primer pockets are a uniform depth. All in the name of more uniform primer flash, ignition.
You will trim brass overall length, then turn the case walls to uniform thickness +/- a couple ten thousandths of an inch.
Now, here's where the bushing comes in. By using differently sized bushings (and possibly futzing with case wall thickness), one can adjust the neck tension on your bullet to produce a more uniform release of the bullet.
All this work is an attempt to reduce group size. There's a website called Benchrest Central where you can learn more about such fascinating uses for your free time. I hung out there for awhile some years back. One of the things I learned, was that despite all the work described above, some top competitors discovered that a slight crimp produced a more uniform powder burn and bullet release in their tests/matches.
BTW, SFAIK, all this is intended ONLY for use in bolt guns, loaded one round at a time. There's no way in heck any bullets so seated are likely to survive the feed cycle of an Mforgery. Some folks might be able to manage to work the process for firearms with manually operated bolts.
The only thing I bother to do for match loads or a couple of specialty bullets is to use an M die to uniform the neck tension and slightly flare the case mouth to help bullet alignment with the case neck.
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Ivan the Butcher
Member
I believe some of the above are true some are... not in line with what I have observed. True: these dies are wasted on semi autos. False: you have to use this type of loaded round in single fed firing. The amount of neck tension works to hold the bullet in place. Enough tension will hold bullets in place in a magazine even under 338 Lapua recoil! You need to develop the load from the beginning with high neck tension! It can increase chamber pressure above maximum in an already existing load.
One of the unmentioned benefits of using bushings to size case necks is; since you don't use a crimp and canalure your brass length can very in length a small amount. Many chambers allow case length to "grow" after firing. The length of a case fired 1 time since length trimming will often be different than one fired 3 times. The use of collets allows case length to very .010 (maybe even much more) and still have uniform groups.
My experience with my 308 Winchester Palma loads shows that .003 OD neck tension holds the bullets in a magazine. My experience with 338 Lapua Mag show .005 works very well. Both of these are holding groups of 1/4 to 1/2 MOA at distance and firm 1/4 or less at short range.
We try to keep neck wall thickness to below .001 variance. If you change brands of match brass the variance will most likely still be below .001, but the total thickness could be .002 different, all you would need is a different sized collet.
I have Collet dies in 223 Rem, 22-250 Rem, 22 BR (Rem), 6 PPC, 6x284, 7mm TCU, 7x57, 308 Win, 300 Win Mag, and 338 Lapua. In each caliber except 338) I have 3 to 8 collets. These very in sizing diameter by steps of .0005 or .001 and sometimes .002 I have the 8 in 6mm (that is the only diameter you can buy .0005 of the shelf! .001 steps are available for everything else.) I also have 8 in 22 because there 2 nominal neck thickness, .010 (for 22 Hornet & 22 BR) & .015 (for most everything else!)
There is one other feature to Collet sizing of necks. You can control the amount of the neck that gets sized. By only sizing 3/4 of the neck's length, you form a tiny shoulder at the base of the neck. For good guns, but without a "Match" or "Competition" chamber, this allows the cartridge to be centered in the chamber (instead of laying on the bottom). It has to do with tiny improvements in group size! (most rifles won't matter!) Steel collets run $12-$17 TiN coated collets run $23-$29 Carbide collets run $50 and up (I've only seen them in 6mm sizes)
Hornady and RCBS use proprietary collets. Redding and Wilson use the same size. I don't know about Forrester. The dies that use these, are more expensive than regular sizing dies! The basic dies have a basic collet depth adjustment, then there are Competition Collet dies with Micrometer adjustments, up to $170 sizer only (plus collets)
You probably should have a pretty accurate rifle to start with before laying out this kind of money for more dies!
Ivan
One of the unmentioned benefits of using bushings to size case necks is; since you don't use a crimp and canalure your brass length can very in length a small amount. Many chambers allow case length to "grow" after firing. The length of a case fired 1 time since length trimming will often be different than one fired 3 times. The use of collets allows case length to very .010 (maybe even much more) and still have uniform groups.
My experience with my 308 Winchester Palma loads shows that .003 OD neck tension holds the bullets in a magazine. My experience with 338 Lapua Mag show .005 works very well. Both of these are holding groups of 1/4 to 1/2 MOA at distance and firm 1/4 or less at short range.
We try to keep neck wall thickness to below .001 variance. If you change brands of match brass the variance will most likely still be below .001, but the total thickness could be .002 different, all you would need is a different sized collet.
I have Collet dies in 223 Rem, 22-250 Rem, 22 BR (Rem), 6 PPC, 6x284, 7mm TCU, 7x57, 308 Win, 300 Win Mag, and 338 Lapua. In each caliber except 338) I have 3 to 8 collets. These very in sizing diameter by steps of .0005 or .001 and sometimes .002 I have the 8 in 6mm (that is the only diameter you can buy .0005 of the shelf! .001 steps are available for everything else.) I also have 8 in 22 because there 2 nominal neck thickness, .010 (for 22 Hornet & 22 BR) & .015 (for most everything else!)
There is one other feature to Collet sizing of necks. You can control the amount of the neck that gets sized. By only sizing 3/4 of the neck's length, you form a tiny shoulder at the base of the neck. For good guns, but without a "Match" or "Competition" chamber, this allows the cartridge to be centered in the chamber (instead of laying on the bottom). It has to do with tiny improvements in group size! (most rifles won't matter!) Steel collets run $12-$17 TiN coated collets run $23-$29 Carbide collets run $50 and up (I've only seen them in 6mm sizes)
Hornady and RCBS use proprietary collets. Redding and Wilson use the same size. I don't know about Forrester. The dies that use these, are more expensive than regular sizing dies! The basic dies have a basic collet depth adjustment, then there are Competition Collet dies with Micrometer adjustments, up to $170 sizer only (plus collets)
You probably should have a pretty accurate rifle to start with before laying out this kind of money for more dies!
Ivan
USSR
Member
Ivan,
Partially resizing the neck is also done with bushing dies. We did it all the time in 1,000 yard F Class Competition.
Don
If you have a factory rifle with a SAAMI chamber and use Remchester brass there is no advantage to using a bushing die.
Much of what benchrest shooters do is just over kill with a standard factory rifle.
At the Whidden custom die website they tell you they get the most concentric cases using non-bushing full length dies. And at Whidden they also sell expander kits with five expanders from bullet diameter to .004 under bullet diameter.
Bushing dies work best with custom tight neck chambers with neck turned brass. And reduce the neck diameter "less" than .004 to prevent inducing neck runout.
And with a standard SAAMI chamber when you reduce the neck diameter more than .004 you will induce neck runout.
The bushing floats inside the die and can move side to side and even tilt when sizing the case neck.
And you have no control over how much your case neck expands when fired in a SAAMI chamber.
And at the Redding website they tell you to use a bushing that will make the inside neck diameter .004 smaller than bullet diameter. And use the expander to open the neck .001 or .002 so your still working the case neck.
Bottom line I get the least neck runout using Forster full length benchrest dies. And the most neck runout with neck sizing bushing dies.
Below are just a few of the .223 dies I tested and then checked the sized cases for neck runout. And the best die was the Forster full length dies with the high mounted floating expander. And Forster will hone the neck of their dies to your desired diameter for $12.00 if you want a custom die. Not in the photo is a Redding full length bushing die that had more neck runout than the RCBS non-bushing neck sizing die.
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Ivan, learned a few things thanks. Almost all I learned about bushing dies I learned from the benchrest crowd. I did preface my comments about other than single shot with SFAIK (so far as I know).
I used to shoot F class tactical and my greatest variable.......was me. I did get better at judging wind, but I found the time spent on being really persnickity about loading technique was better spent on dry fire and other things directly related to my own performance.
Boots Obermeyer had a story on his website about how he loaded with extreme care over the winter and gauged and sorted his rounds so he'd have nearly perfect ammo ready for competition (across the course). Came the first match, he set a new state record, and of course, credited all the care he'd put into ammo production.
When he got home, he discovered he'd accidentally grabbed the wrong ammo box. He shot the new record with the cull ammo he'd set aside for close range practice.
I used to shoot F class tactical and my greatest variable.......was me. I did get better at judging wind, but I found the time spent on being really persnickity about loading technique was better spent on dry fire and other things directly related to my own performance.
Boots Obermeyer had a story on his website about how he loaded with extreme care over the winter and gauged and sorted his rounds so he'd have nearly perfect ammo ready for competition (across the course). Came the first match, he set a new state record, and of course, credited all the care he'd put into ammo production.
When he got home, he discovered he'd accidentally grabbed the wrong ammo box. He shot the new record with the cull ammo he'd set aside for close range practice.
How many shooters here have a custom made rifle in 22 PPC shortened .05” where the barrel has been lapped to the receiver for 100% thread contact?
How many here have their triggers set to 1/4 of an once?
How many here go to the extensive case prep that was in this article?
How many here jam their bullets into the rifling?
Bottom line, too many people think if they copy what benchrest shooter do with their custom rifles with tight neck chambers it will help their off the shelf factory rifles.
The OP question was "What’s the significance of using bushing dies?"
Answer, spending much more money on bushing dies that will have more neck runout than a standard full length die.
When reducing the neck diameter .004 or more with a bushing die it is recommended to reduce the neck diameter in two steps to help reduce neck runout.
Now ask yourself "WHY" so many reloaders prefer the Lee collet die over bushing dies.
Answer, they get "LESS" bullet runout with a Lee collet die vs a bushing die.
With a bushing die and not use the expander you will need to neck turn your brass.
If you do not neck turn and use the expander Redding recommends sizing the neck .004 smaller than bullet diameter. Meaning you are still working the cases neck.
Below is a Forster full length benchrest die with its high mounted floating expander. And these Forster dies produce the most concentric resized cases of any die I have ever owned. The neck of the case is held and centered in the neck of the die when the expander enters the case neck. And this prevents the expander from pulling the case neck off center and inducing case neck runout.
Below is the Forster benchrest seating die that holds the case and bullet in perfect alignment during bullet seating. And standard seating dies do not do this and can allow the bullet to tilt during seating.
The Forster die is much cheaper than a bushing die and their benchrest seating die is cheaper the Reddings. And with both of these dies you will reload cartridges with little to no bullet runout.
"What’s the significance of using bushing dies?"
Spending more money for a bushing die in a off the shelf factory rifle that you didn't need to spend.
Am using the bushing die for 308, mainly because of the wide disparity of brass thickness's in the varying kinds of brass I use. Big difference between Win and Fed brass, and this affects the case neck tension significantly. And I don't use an expander plug afterwards, unless the brass is going to get trimmed, in which case it gets neck sized down again. I use smaller bushing dia for the Win brass.
By not pulling the case neck out of alignment, and using a Redding/Forster BR seater, you add to the probability you are increasing the precision of your rounds.
With the normal RCBS/Redding dies I own that have expander plugs, any of them can be made free floating by using a carbide button and loosening the stem. . It helps to keep the neck aligned as bigedp51 describes. Or you can self align the stem in the neck, then lock it in, but I do not think it works as well.
Am not using the bushing dies for other calibers, as most of the calibers I am reloading have the variation of brass neck thickness 308 has.
By not pulling the case neck out of alignment, and using a Redding/Forster BR seater, you add to the probability you are increasing the precision of your rounds.
With the normal RCBS/Redding dies I own that have expander plugs, any of them can be made free floating by using a carbide button and loosening the stem. . It helps to keep the neck aligned as bigedp51 describes. Or you can self align the stem in the neck, then lock it in, but I do not think it works as well.
Am not using the bushing dies for other calibers, as most of the calibers I am reloading have the variation of brass neck thickness 308 has.
Thanks for this! I had not heard of this story.
Toilet paper bullets! Ha!
It's hard to tell from the OP's question exactly what his need/hope/desire is - perhaps it's nothing more than wanting to understand a tiny slice of the shooting world a tiny bit better.
The arcana of the extreme precision shooting crowd might elude most of us - for sure, count me amongst the vast practical shooting majority. But at some point what they do - what they did there in Houston - whispers something that we all might hear.
My ancient copy of The Bullet's Flight From Powder to Target is full of that kind of stuff, albeit from a hundred years earlier. Somewhere, Harry Pope is smiling.
Thanks again...
The Forster full length benchrest die holds and centers the case neck in the neck of the die when the expander enters the case neck. Meaning there is no way for the expander to pull the case neck off center.
And by adding a carbide floating expander to a standard RCBS, Redding etc spindle assembly you have the same problem. You have a expander that sits lower with nothing centering the case. Meaning the expander can still pull the necks off center. And the carbide expander I ordered for my Redding .243 had a diameter of .2428. Meaning .0002 smaller than bullet diameter and the carbide expander is too hard to sand down in diameter.
A bushing floats and can move side to side and even tilt when reducing the neck diameter .004 or more. And Redding recommends reducing the neck diameter in two steps when reducing the neck .004 or more. And this is to help reduce neck runout using a floating bushing.
Below I have fitted a modified Forster expander assembly to a Redding full length 243 die to reduce neck runout. Now look at how long and the surface area of the longer Redding expander. It is no wonder why some reloaders complain about using expander and how they can pull the neck off center.
Bottom line, you would be amazed at how many people do not lube the inside of the case neck and then complain about expanders.
And the shame of it is you can get less neck runout using a cheap Lee die than a bushing die because the Lee expander is held centered by the dies expander collet and can not move.
And again, at the Whidden custom die website they tell you they get the most concentric cases using non-bushing full length dies. And at Whidden they also sell expander kits with five expanders from bullet diameter to .004 under bullet diameter.
And my Forster full length benchrest dies produce very concentric cases and are cheaper than any custom made Whidden die and cheaper than Redding dies.
And by adding a carbide floating expander to a standard RCBS, Redding etc spindle assembly you have the same problem. You have a expander that sits lower with nothing centering the case. Meaning the expander can still pull the necks off center. And the carbide expander I ordered for my Redding .243 had a diameter of .2428. Meaning .0002 smaller than bullet diameter and the carbide expander is too hard to sand down in diameter.
A bushing floats and can move side to side and even tilt when reducing the neck diameter .004 or more. And Redding recommends reducing the neck diameter in two steps when reducing the neck .004 or more. And this is to help reduce neck runout using a floating bushing.
Below I have fitted a modified Forster expander assembly to a Redding full length 243 die to reduce neck runout. Now look at how long and the surface area of the longer Redding expander. It is no wonder why some reloaders complain about using expander and how they can pull the neck off center.
Bottom line, you would be amazed at how many people do not lube the inside of the case neck and then complain about expanders.
And the shame of it is you can get less neck runout using a cheap Lee die than a bushing die because the Lee expander is held centered by the dies expander collet and can not move.
And again, at the Whidden custom die website they tell you they get the most concentric cases using non-bushing full length dies. And at Whidden they also sell expander kits with five expanders from bullet diameter to .004 under bullet diameter.
And my Forster full length benchrest dies produce very concentric cases and are cheaper than any custom made Whidden die and cheaper than Redding dies.
Sorry to disagree, but prefer a floating carbide expander (they are short) over a fixed one, when I use one. For me a non locked down floating expander aligns itself with the case neck, meaning the fired case neck determines where the expander goes.
Lots of ways to skin the cat, also helps to insure your dies are squared up, and I use a fired case for that.
Lots of ways to skin the cat, also helps to insure your dies are squared up, and I use a fired case for that.
Below on the left is a standard RCBS expander raised as high as it will move. On the right is a Forster high mounted floating expander and spindle assembly. And the Forster expander assembly will fit RCBS dies and reduce neck runout vs letting the RCBS expander float.
On the down stroke of the ram if you have any dings in the rim it will cause the case to tilt in the shell holder. And a floating expander will not center the tilting case.
The difference is the high mounted floating Forster expander enters the case neck while it is held and centered in the neck of the die. Meaning the case is straight and inline with the die when the neck is expanded.
You can put a small rubber o-ring under the expander spindles lock nut and let it float and decrease neck runout. Or add a floating carbide expander to reduce neck runout. But the above two methods do not ensure the case will be straight when the expander enters the case neck.
Below under the Redding expander lock ring is a rubber o-ring that allows the expander to float and self center in the neck of the case. And at the same time the case neck is held and centered in the neck of the die.
Below the co-ax washer is a rubber washer that allows the expander to float. And as you can see the case neck is held and centered in the die when the expander enters the case neck.
Bottom line, no low mounted expander even if it floats will reduce neck runout as much as the Forster designed expander. And my runout gauges do not tell lies.
That being said the best part about reloading is the person pulling the press handle decides how to do it...............even if they are wrong.
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