neck turn or FL bushing size

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milboltnut

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neck turn or FL bushing size (alignment/concentricity sized case axis of the cartridge.)

Anybody just FL bushing size and not neck turn ?

If you just FL bushing size, what are your runout/neck thickness measurement?

Does neck bushings make necks more concentric? I know about annealing. I anneal, FL without expander ball, expander mandrel, neck turn, and use a Forster BR seater and Wilson inline seaters.
 
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No, bushings are just another resizing device. If your neck walls are thicker on one side than the other, they will still be that way after running through a bushing. The advantage to bushings is being able to pick one that resizes the neck just enough to grip the bullet, but not enough to need expanding so you get to skip the expanding step. For concentricity of the finished round, it works best with necks already turned to uniform wall thickness all around. But if you are making all your necks the same wall thickness, then you can have Forster hone a standard die's neck to the OD you need and get perfect case concentricity and not have to buy bushings.
 
Yeah I agree.... but as far as the honed die, that would limit neck tension, but for me I use a expander mandrel .001 under bullet diameter and am golden.
 
The honed die would give you the same result if you request the right diameter. The standard dies require an expander to be used after they resize brass because they over-resize the vast majority of necks. They do this because they have to work with brass at the thinnest end of the range of neck wall thicknesses made. When a neck isn't actually at that minimum thickness (very few are) it gets over-resized and then you need an expander to bring it back up to the desired bullet-gripping interference fit.

If we suppose your case necks exhibit about 0.001" of spring-back after either resizing or expanding, then your current expander is expanding to bullet less 0.001" and when you withdraw it the neck springs back inward about another 0.001" to leave about 0.002" of neck/bullet interference fit. That's a good number.

To get the same number from a honed die, you have the neck honed from the too-small standard size to about 0.001" under the final size you want. In other words, about -0.003" below bullet diameter. Then when it squeezes a case down, the case will spring back out by about 0.001" at the neck when you withdraw it from the die, and you will, once again, have -0.002" under bullet diameter. It's the same amount of spring-back, just in the opposite direction; outward rather than inward.
 
Sierra Bullets has been using full length bushing dies without expander balls on unprepped cases for decades. Their best match bullets test quarter MOA at 200 yards.

Before that, they honed out the necks on conventional full length sizing dies and tossed the expander ball. Got the same accuracy.

Either is the only way to end up with case necks perfectly aligned to the case shoulder's center so bullets are well aligned to bore center when fired.
 
Uncle Nick

The honed die would give you the same result IF you request the right diameter.(I lucked out with the right expander mandrel, so you really don't know until you try it)The standard dies require an expander to be used after they resize brass because they over-resize the vast majority of necks. They do this because they have to work with brass at the thinnest end of the range of neck wall thicknesses made. When a neck isn't actually at that minimum thickness (very few are) it gets over-resized and then you need an expander to bring it back up to the desired bullet-gripping interference fit.

If we suppose your case necks exhibit about 0.001" of spring-back after either resizing or expanding, then your current expander is expanding to bullet less 0.001" and when you withdraw it the neck springs back inward about another 0.001" to leave about 0.002" (NOT A GOOD NUMBER) of neck/bullet interference fit. That's a good number.

To get the same number from a honed die, you have the neck honed from the too-small standard size to about 0.001" under the final size you want. In other words, about -0.003" below bullet diameter. Then when it squeezes a case down, the case will spring back out by about 0.001" at the neck when you withdraw it from the die, and you will, once again, have -0.002" under bullet diameter. It's the same amount of spring-back, just in the opposite direction; outward rather than inward.
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Totally disagree...What good is a honed die.... you are stuck with one neck tension diameter, then what if it doesn't work, at least bushings or mandrels aren't part of the die.

Your neck tension of .002 (is standard neck tension for FL sizing dies) or even .003 is too general and may not be sufficient enough.

Your first reply answered my question. I shouldn't have came back with a rebuttle of neck tension. Sorry.
 
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BartB

Sierra Bullets has been using full length bushing dies without expander balls on unprepped cases for decades. Their best match bullets test quarter MOA at 200 yards.

Before that, they honed out the necks on conventional full length sizing dies and tossed the expander ball. Got the same accuracy.

Either is the only way to end up with case necks perfectly aligned to the case shoulder's center so bullets are well aligned to bore center when fired.
Click to expand...

Sounds good.. FL neck bushing dies or honed dies. Sounds like a hone job aligned the rest of the die with the neck portion. Honed dies are cheaper than FL neck bushing dies and varies bushings.

Why did Sierra go to neck bushing from honed dies if there's no difference ?
 
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Sierra uses full length sizing dies with bushings because they are cheaper in the long run.

One die with several bushings correctly resizes a wide range of bullet interference fits caused by big spreads in neck thickness and bullet diameters.
 
more versatile... more like cartridge verities with the same bullet diameter. That's what I can understand from what you said otherwise....

If I'm wrong I really wish you would be more plain. Thanks.
 
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No reason you can't do both, do a 90% skim cut then use a bushing die. I did it that way for years.


Lately though I turn down to .012 wall thickness, then do a FL resize using Lee FL dies minus the expander button then expand using a mandrel. Best concentricity I have ever experienced
 
Totally disagree...What good is a honed die....
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Bart has explained it produced the same accuracy as the bushing die for Sierra.

you are stuck with one neck tension diameter, then what if it doesn't work, at least bushings or mandrels aren't part of the die.
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You address this by knowing what works for you before you get the die honed, and then get it honed to produce the proven good interference fit (aka, neck tension). It then gives you better case concentricity and saves you the expansion step which means it works the brass less and your cases last longer.

Your neck tension of .002 (is standard neck tension for FL sizing dies) or even .003 is too general and may not be sufficient enough...0.002" (NOT A GOOD NUMBER)
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I don't think weren't following what I said. I was suggesting that 0.002" interference fit is probably about what you actually have now. I say this because you said you use an expander -0.001" below bullet diameter. Brass is a little springy, even when annealed. The circumferential tension on that brass spring is what holds bullets in a case neck. Thus, case necks pushed outward by an expander spring back down in diameter a little after the expander has passed through the neck. As a result, your neck is a little narrower than the expander after the expander is pulled out. If you have about a thousandth of spring-back after the mandrel is withdrawn (a common amount), you would have roughly 0.002" of final interference fit when the spring-back has been included.

The 0.003" number I mentioned is not an interference fit, but a honed neck or neck bushing diameter suggestion. It is based on the assumption, again, that the brass will spring back 0.001", but this time it would spring outward because you are sizing it down. After springing outward, it would again leave you with the same final -0.002" that is about what I suspect you are ending up with now.

So it was all about trying to match what you use have now.

You can prove this to yourself by measuring around the outside of case necks below the mouth and over top of where the seated bullet's full diameter will be. Do this to cases after you have expanded them, and then do it again after you have loaded them and the bullet has been seated under the measuring point. Average the empty case neck numbers and average the after-bullet-seating numbers. The difference between the two averages will be the average neck-to-bullet interference fit or neck tension you have actually been getting. I recommend measuring 30 because cases this way because each case can spring a little differently and the necks can be slightly out of round after expansion, so doing that many will do a good job of averaging out that sort of error.

It is perfectly possible that I am wrong about how much spring to allow for you because I don't know the caliber you are loading nor exactly how springy your annealing method is leaving your necks. I only know there will be some spring-back because if there were none, the necks wouldn't hold onto your bullets. Measuring as I described will tell you how much spring-back you are actually getting. I've seen about 0.001" of spring-back frequently, but I've also seen half that and twice that depending on how hard the neck is. Once you know how much you are actually getting, you will know what to allow for with bushings or with a honed neck, either way.
 
Makes sense to have a honed die exclusively for a particular load... yeah ok, I can see that. I just anneal, FL - expander ball, expand mandrel, seat. Multiple mandrels, multiple bushings... honed die, same outcome.. Only your skipping expanding. Sounds like a plan.

Uncle Nick
Brass is a little springy, even when annealed, so case necks pushed outward by an expander usually spring back down in diameter a little after the expander has passed through the neck.
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My neck turning pilot glides very smoothly over my annealed, expand mandrel brass. I expand with, in my estimation, very little to no spring back. .306 pilot, .307 mandrel. I run the necks by the expander 3 to 4 times... which spring back is nill to none otherwise it would be hard to pass over the pilot. It was before I anneal and pass three or four times.

I have a half inch group, before neck turning/mandreling and neck turning/mandreling almost one hole group. I don't concern myself with OD seated rounds. The pressure all feels the same, when I seat the bullets and the outcome on paper is what I content with and I doubt it will change with the same bullet, brass (process) powder charge, etc.

You are correct though about .002 to .003 being general. I understand about what you said having the honing done to a specific diameter to allow for a specific springback diameter. Forster will hones to this... but like you said, you can have it honed to where ever you want them.

Sounds like a good idea.

.328 OD case neck .329 OD seated bullet. 25 rounds all the way around.
 
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SAAMI's glossary of industry terms doesn't include "neck tension."

Instead, they use bullet pull or extraction force. The amount of force in pounds required to pull or push the bullet out of the case.

Example..... if a 30 caliber bullet needs 10 pounds of force to push it out of the case neck, it'll move when about 130 psi is in the case. Bullet cross section area is about 1/13th square inch. 1/13th of 130 is 10.
 
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Redding's bushings don't resize necks all the way to the shoulder. Some years ago I asked them why and their response was the unsized part helps center the case neck in the chamber neck.
 
thanks guys

I can see if a neck isn't turned it can seat crooked bullets or if while seating with a standard seater. I noticed my 300 Bee stem in the RCBS seater is longer and deeper to meet the ogive. My Forster seater has a chamber style sleeve with a bullet guide at the top .0015 clearance and the stem an ordered VLD. I tossed my RCBS case master, once I saw the major group improvement, with bedding of course.
 
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I use redding bushing dies with and without expander . I don’t turn my necks and I use either the Forster or Redding competition seater die . My run out sucks :o haha
 
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