Neck turning: outside turning or interior reaming?

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adcoch1

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So I am looking into neck turning tools, primarily for uniforming 300 blackout, 221 fireball, and maybe 45 raptor in the near future, and I am really curious which option is best? I can easily see how both might work, but with interior reaming you could end up with a step like old 38 wadcutter brass. Has this been an issue for anybody? Looking at tools and also wondering what brands people out there are using and liking. want something better than a shellholder in the lathe.

So, advice? ideas? What works for you guys?
 
Though inside neck reaming is good for some applications I find it unnecessary for Things like 300 BLK. I do turn necks on my precision 308 loads and have great concentricity and very low runout. Of course that's with the right dies too. Turning necks is generally for precision loads. How precise do you want your loads? The good thing about neck turning is you only do it once.

Turning necks on formed brass that is too thick for blackout can make most all 223 brass usable. Are you forming 300 BLK?
 
Outside turning is my preference after forty years of reaming. Better concentricity equals better results.
 
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So I am looking into neck turning tools, primarily for uniforming 300 blackout. . .
I'm not squeaking the last bit of accuracy out of 300 BO, but if you need to neck turn I think you need to do a better job sorting by Headstamp before converting. Choosing wisely will let you skip turning and annealing.
 
Though inside neck reaming is good for some applications I find it unnecessary for Things like 300 BLK. I do turn necks on my precision 308 loads and have great concentricity and very low runout. Of course that's with the right dies too. Turning necks is generally for precision loads. How precise do you want your loads? The good thing about neck turning is you only do it once.

Turning necks on formed brass that is too thick for blackout can make most all 223 brass usable. Are you forming 300 BLK?

I have formed a few (like 20) blackout brass, but the thickness of the necks was all over the place. headstamp sorting is the best answer to start, but if I am going to chop down brass I don't want to discard it if it happens to be too thick. And I plan on making some 221 fireball formed brass too, so I am really looking into neck turning. Ironically, I am not yet at the point with long range shooting to actually need the accuracy improvements that normally drive people to neck turning as an accuracy step.
 
Outside turning is my preference after forty years of reaming. Better eccentricity equals better results.

I haven't done it quite that long but I agree. I turn for tight neck chambers so I'm chasing perfection. But you should see more consistent results by outside neck turning vs reaming. For the cost of the turning tool and expander I probably would just choose brass that didn't need those steps. 223 brass is plentiful right now.

You didn't ask this but here goes. I prefer the neck turning tools made by the custom makers over those made by reloading companies. K&M, PMA, 21st Century, Sinclair and Hart, just to name a few. The exception is the little tool made by Forster. The accuracy is there but its not as easy to adjust.
 
I heard a podcast the other day with the head of products for Redding as an interview guest. He said he thought the idea of neck-turning to fix concentricity issues was a fool's errand. His argument was that, if there is a serious difference in one side of the brass versus another (i.e., non-concentricity after sizing), then that same non-concentricity will be present throughout the body of the brass, and it will never be up to benchrest levels of accuracy. He said neck-turning is to fit a tight chamber, not to fix (or cover up) concentricity issues. Pretty sure it was an episode of the Triggernometry podcast; I think it was this one maybe (https://www.stitcher.com/podcast/the-bloke/the-triggernometry-show/e/57317023)

I have no basis for an opinion about this, but it seemed relatively sensible to me... and very contrary to my prior understanding.
 
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He's right, buy good brass, don't waste time trying to make a silk purse from a sow's ear.

I used to ream then turn when making 6 PPC from .220 Russian.
 
Some brass inside the neck looks like a wash-boarded dirt road, so I would ream first, then neck turn to fit a .262 neck. That way I would have a nice smooth surface inside and out and neck tension (consistence) seemed to benefit from it.
 
All depends where your doughnut is living when you decide to deal with it - or in the case of chattered necks, where the damage you’re trying to solve might exist.
 
I have made 30 Herrett cases out of .225 win that required neck turning.
.225 win brass is thicker walled and a higher tensile than 30-30 brass, and so has a smaller case volume, or so I thought, the reason I went thru this exercise:uhoh:.
After forming, the necks needed to be turned so the case would chamber with a bullet seated.
I turned the OD because it was way easier/cheaper to do with an adjustable single point tool on the manual case trimmer I had.
Going the reamer route, I would have to buy a reamer, maybe even 2 before I got the size right:thumbdown:.
The single point tool has a big radius on the cutting edge so it did not leave a big step at the shoulder end of the cut, but more of a blend.
OK, that's why I recommend turning/ not reaming :thumbup:
whew, sorry for the bloviating right there,
:D
 
I have made 30 Herrett cases out of .225 win that required neck turning.
.225 win brass is thicker walled and a higher tensile than 30-30 brass, and so has a smaller case volume, or so I thought, the reason I went thru this exercise:uhoh:.
After forming, the necks needed to be turned so the case would chamber with a bullet seated.
I turned the OD because it was way easier/cheaper to do with an adjustable single point tool on the manual case trimmer I had.
Going the reamer route, I would have to buy a reamer, maybe even 2 before I got the size right:thumbdown:.
The single point tool has a big radius on the cutting edge so it did not leave a big step at the shoulder end of the cut, but more of a blend.
OK, that's why I recommend turning/ not reaming :thumbup:
whew, sorry for the bloviating right there,
:D
Good info, thanks! What brand tool did you use?
 
Good info, thanks! What brand tool did you use?
The neck turning head is part of a Lyman (or Lee:uhoh:) Case trimmer kit I bought a long time ago.

It could have been an accessary at the time, or a non Lyman add-on made by someone else.
I'm thinking this because I've been to the Lyman site and everywhere else and cannot find it.
I looked in all the Lyman case trimmer kits sold today, and did not see a neck turning head.
I did find replacement cutters for it at several websites but not the complete assembly:scrutiny:.
I'll take a look at what I have and check it for any markings.
:D
 
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I have formed a few (like 20) blackout brass, but the thickness of the necks was all over the place. headstamp sorting is the best answer to start, but if I am going to chop down brass I don't want to discard it if it happens to be too thick. And I plan on making some 221 fireball formed brass too, so I am really looking into neck turning. Ironically, I am not yet at the point with long range shooting to actually need the accuracy improvements that normally drive people to neck turning as an accuracy step.
Easy solution to forming 300 BLK is to get nothing but brass that doesn't have the thick necks. For instance Buy all LC 223 brass. Secondly use a RCBS Small Base die. It will form the brass that will fit your gauge and gun.

Now A RCBS small base sizing die will push the shoulder back more than a standard die set but you can adjust it after your brass is formed and fired to not push back as much. That is up to you to find what fits your gun. I backed it off until the brass stopped fitting in my case gage and went back a little until every piece fits. This is the easy and trouble free way to form 300 BLK brass.

FWIW I started with a LEE to form my brass and had to anneal before forming and really get down on the die after forming to get good reliability. Now I run 100% since switching dies. Don't get me wrong, you can make it work with about any FL die I know of but the small base dies ended all troubles for me.
 
Now A RCBS small base sizing die will push the shoulder back more than a standard die set
It has always been my understanding that they were just tighter in the body. There is no reason for it to need to move the shoulder more.

Correct me if I am wrong. With a link to it would be nice.
 
From RCBS:

The Small Base Sizer Die is for bottleneck type cases used in tight-chambering semi-automatic, pump or lever-action firearms. The sizer resizes cases below SAAMI minimums, reducing the shoulder and body by a few thousandths. It also de-primes the case. Note: Not recommended for ammunition used in bolt-action rifles.

Use to be just the base......some "educated" being at RCBS added more......unfortunately. However, there are some guns that still require one....my 7.62 Remington AR 10 clone does.

My argument has always been.....if you want ammo that is sure to load in anything that comes your way....use one. If you are just loading for what you have now, and regular dies work, no reason to use one. But that may mean, when you sell the gun, you may get stuck with a lot of ammo that won't be reliable in the next one.....and most people won't (shouldn't) buy someone elses reloads.

BTW, my small base RCBS dies (.223 and .308) do NOT size smaller than minimum SAAMI specs as stated above, but they are near that minimum.

I'm thinking spring-back has something to do with that.....some old brass resists sizing and springs back more than other brass, especially true with some of the older or MG LC brass that I've sized.
 
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From RCBS:

The Small Base Sizer Die is for bottleneck type cases used in tight-chambering semi-automatic, pump or lever-action firearms. The sizer resizes cases below SAAMI minimums, reducing the shoulder and body by a few thousandths. It also de-primes the case. Note: Not recommended for ammunition used in bolt-action rifles.
Poorly worded IMHO. Does not make it clear.

I would still assume by shoulder they would mean diameter. Pushing the shoulder back only makes head clearance greater, which can be a negative. I have only had one die that would not move shoulders enough, and I consider that defective.

I may call RCBS. If it does move the shoulder a tad more, it shouldn't be much (Another .001?). And we should be controlling that with die adjustment anyway.
 
Good point....Have to agree.... I'm not sure the writer was an engineer either.....nor do I think they get engineers to proof read. "below SAAMI"? Now why would you want to do that......unless the springback factor.....but all brass doesn't do a lot of that. My experience with it hasn't been that drastic, sizing-wise.....just a little more than regular sizing to making it sure in Autos, levers, and sliders. I'm happy with them.
 
Outside turning is my preference after forty years of reaming. Better eccentricity equals better results.

RCBS makes a reamer die, the reamer die sizes the case. The die aligns a reamer with the case making it the perfect tool. Outside of me I do not know of another reloader that has one 'OUTDISE!' of owners of owners of Lee Target Model dies sets. The die set worked because of the Lee reamer system.

And then there are donuts, I have learned there is no room on this forum to discuss donuts.

F. Guffey
 
I bought the 21st Century neck turner, along with their mandrel neck expander die.

I ran tests using 223 brass, all annealed. With everything else the same, I made two load workups, 4 charges each, and the only difference between the two sets of brass was turned or not turned. I got much better standard deviation with the neck turned brass - it was significant. At 100 yards I did not see much difference in accuracy, but the lower standard deviation should mean better accuracy downrange.
 
I may call RCBS. If it does move the shoulder a tad more, it shouldn't be much (Another .001?). And we should be controlling that with die adjustment anyway.

One day someone is going to explain to me how they move the shoulder back, I find it impossible to move a shoulder back with a die that has full body support.

After all of these years I would think a reloader would learn to compare instead of making this stuff up. I have small base dies, some of them are called 'BAR' dies; what does that mean? BAR dies came from RCBS, they said the BAR stands for 'BROWNING AUTOMATIC RIFLE'. Most reloaders assumed there was a difference between BAR dies and standard over the counter RCBS DIES IN 30/06, 300 WIN MAG, 270 W etc. In the RCBS Glossary of Terms they escribed a small base die as being a good fitting standard die. If I thought it was necessary to use a small base die I would him the case between the deck of the shell holder and case head and then make sure the die made it to the top of the shell holder.

Adding the shim increased the presses ability to overcome the cases ability to resist sizing. And shims come in increments of .001" for general use.

F. Guffey
 
@Walkalong & @GW Staar - that RCBS page is poorly worded.

Side by side, when I set both to bottom out on the shellholder, the headspace is nominally the same for the small base vs. standard FL sizing die. The problem, of course, is that whenever I Small Base size, I want to run it as deep as I can, while when I do a standard FL size, I only want to bump sufficiently to offer 1-2thou chamber clearance. So while the die itself may not actually be any different for headspace, how we use the dies and how they are set up, due to their respective nature, does change. The small base should be set up to touch the shell holder to size the base as deeply as possible, whereas the FL sizer might not be touching so the headspace better matches my rifle chamber.

If I am honest, I have wanted to cut the shoulder and neck out of my small base dies for many years. The fact I want to minimize my base diameter doesn’t also mean I want to minimize my headspace length, so I would love the ability to separate these steps. The only reason I haven’t done so, is the realization that it would likely introduce some opportunity for runout. My only satisfactory solution has been to NOT small base size every time, and to NOT small base size in my batch right before a match where extreme precision is demanded.

Here’s the big difference I have experienced between outside turning and inside reaming:

FIRST: both work to uniform brass necks, but the reloader has to understand how both systems really work so they can use them properly, designing an appropriate process around their gear. Otherwise there’s opportunity to trip yourself.

SECOND: I fervently prefer lathe turning, evidence for why I hold this opinion is detailed below.

NOTE: I could be completely wrong in this, and would love to get better educated, but as a product design engineer, including some tool & die design work, with disposable income to have bought and compared all of these methods over the years, and a 25+ year reloader using this gear, these are my observations for the two options...

Turning: you’re forcing the brass over a mandrel and wedging it througha controlled depth cutter gap. In principle, this is not so different than a Doctor’s knife or wood planer - force material through a fixed gap with a cutter on one side to make it fit, and guess what - it comes out the other side at the size of your gap. If your neck is oversized and loose on the mandrel, you still yield consistent thickness because you’re forcing the neck between the annular gap between the mandrel and the cutter, and the slack between the neck and mandrel would be pushed to the opposite side. If the neck is sized too small for the mandrel, either it gets sized when forced onto the mandrel, or it has to be expanded to fit, so it really can’t be undersized. Since the reloader picks the gap, as long as the brass is thick enough to fill the gap, it will cut to uniform thickness (and the reloader may choose to NOT make a full perimeter cut, depending upon their intent for the brass, cleaning up to 90% cut might be sufficient. A guy can buy their mandrel to match their expanding mandrel, such the resulting brass is ready to be loaded (if a guy didn’t want to anneal and size/expand after turning anyway). Brass chips stay outside of the case, so a guy doesn’t have to worry about sending them down their bore if they don’t all shake out. Pretty hard to screw this up, and you have ultimate control over the thickness.

Reaming: you’re holding the brass in the die, and reaming a hole. You have no control over the brass thickness, at all. The thickness is set by the die Neck ID and reamer OD. To control thickness, a reloader would have to have an entire set of precision ground reamers of varying OD. The neck MUST be expanded to be contacting the ID of the die neck, otherwise it can float and the reamer can cut the necks eccentrically. If you have obloid necks, or eccentric necks of non-uniform thickness, such one side is making contact but not the other, the reamer may not cut concentrically to the neck OD. To mitigate all of this, the reloader needs to mandrel expand to larger than the die ID, ream, anneal, size, and expand again. We can’t control the dimension, so we are forced to settle for exactly the thickness the gear produces, and accept the fact that might mean we cannot uniform thinner necked brass, and might mean we have to cut more off of thicker brass than necessary to create uniformity (debatably reducing brass life by making the neck thinner and more prone to split). All of the brass chips end up inside the case, which doesn’t make me feel great, as sending brass buckshot down my bore at 3,000fps just doesn’t make me feel warm and fuzzy. I am ridiculously stringent about washing and dumping chips after reaming before loading. The real downside I see in reaming, above everything else above, is the fact the brass needs to be oversized. I run fired brass (or at least minimally sized) into the reaming die to ensure it is hard against the wall, which might mean in final FL sizing, I push the shoulder back more and end up with some non-reamed shoulder material pushed up into the neck (or really, the neck pushed down into the non-reamed shoulder mass). So my effort to eliminate a step/doughnut and to uniform necks might actually produce a step/doughnut.

Guys debate back and forth if you can push a step to the outside, or push a doughnut to the inside, whether with gear on the bench or firing in the chamber. It’s irrefutable when you do it for yourself - ream a step into a neck and then run an oversized mandrel, you’ll see a doughnut on the outside. The efficacy of that dimensional shift is highly debatable and nearly impossible to quantify, however. Firing certainly moves everything to the inside, but again, to what efficacy remains in question. Axial disparity in neck thickness is a critical problem - the only satisfactory answer I have found is to turn/ream deeper than I might have expected, and let brass flow where it will.

Like I said, I developed the above opinions by analyzing the results of these processes through the eyes of a reloader, as well as an engineer. If someone can disprove any of it, I’d be happy to find new information to better refine my reloading process.

I like quantitative control, and I like simplified process designs. On a Lean Manufacturing basis, much of the preparation steps to optimize around reaming are not value-add. Turning gives me control over the product dimensions, eliminates multiple process aspects where error can be introduced, and reduces some of the processing steps I have to go through. So I prefer Turning.
 
Thank you Varminterror for the explanation of the processes, this is what I was looking for. I understand the fundamentals of both methods, but not having done so yet, the finer points I haven't dealt with. I was concerned about the ability to remain concentric while reaming, and if turning on the outside would cause a step or possible doughnut when loading. So, again, thanks to all of you for sharing your info and experience.
 
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