Neck Runout During Neck Sizing

[Pvt.Donut]

I've managed to narrow down where runout is being added in my prep cycle. From fire form thru cleaning and body sizing my necks are showing .001" Runout (+/- .001). I'm neck sizing with a Redding Type S Neck Die, using Redding Dry neck Lube. After neck sizing my brass is coming out with .005-.006" of runout (this is both occurring on my MEC Marksman and my Redding Big Boss press). Shoulders are still around .001 but my necks get wonky. Only thing I've tried that remedies this is maybe fully trimming my brass flat before neck sizing but I can't trim every firing or my cases gradually become shorter and shorter.

Any suggestions on what I can try to reduce neck runout during neck sizing?

 

[Mike402]

I had the EXACT same issue with that neck die. I solved it by shifting towards the Lee Collet neck die & Redding body die combo.

However I anneal every firing with an AMP and found that the standard mandrels didn't provide enough neck tension, so I had to buy undersized mandrels from Lee. All is well in the world now.

 

[BoydAllen]

Regular neck dies, be they bushing or one piece are bad about doing just what you have described, because there is nothing that aligns the case prior to its neck being sized. There is one exception, the Lee collet die. Those dies work entirely differently, and I think that if you try one, you will find that your results are much better. There is a learning curve. You need to read the instructions, and take the die apart so that you can see how it works. Don't run a set die without a case, and remember that you change neck tension by changing to mandrels that have different diameters.

 

[avidflyer]

I've managed to narrow down where runout is being added in my prep cycle. From fire form thru cleaning and body sizing my necks are showing .001" Runout (+/- .001). I'm neck sizing with a Redding Type S Neck Die, using Redding Dry neck Lube. After neck sizing my brass is coming out with .005-.006" of runout (this is both occurring on my MEC Marksman and my Redding Big Boss press). Shoulders are still around .001 but my necks get wonky. Only thing I've tried that remedies this is maybe fully trimming my brass flat before neck sizing but I can't trim every firing or my cases gradually become shorter and shorter.

Any suggestions on what I can try to reduce neck runout during neck sizing?

Had the exact same problem....swapped out for wilson bushings and the problem went away..... size a case with no bushing and check the run out see if its coming from the bushing mine was cocked and off center wilson bushing foxed it

 

[jepp2]

Any suggestions on what I can try to reduce neck runout during neck sizing?

When I use Redding S dies with the Redding Titanium Nitride bushing and no expander, I get neck runout of 3-5 thousandths. This is multiple calibers, different presses, different brand brass and so on. When I switched to Whidden bushings my runout drops to around 2-3 thousandths.

When I used a FL die and a carbide expander, if I hone the die neck so the expander has 0.001" or less work to do, I get TIR of 0.001" or less. Using a Lee Collet die I get TIR of 0.001" or less.

Folks try to tell me that I'm not using my Redding Bushing dies correctly as they get great results. I don't, and I have tried many different things to improve.

So I mostly use either honed FL sizing dies, or Redding body dies and Lee collet dies.

 

[Cryhavoc]

Tag

 

[dmoran]

With any bushing die, the bushing needs to free float in the bushing chamber. Seen it a couple times where either the bushing chamber needed polished out and/or the chamber cap tightened down to much restricting the bushings free movement. A dirty bushing chamber can also restrict free movement.
Each time before I put a bushing die into my press, I always shake it to assure the bushing is floating. I also clean the bushing chamber (and entire die) often.
Donovan

 

[jepp2]

With any bushing die, the bushing needs to free float in the bushing chamber.

I agree 100% with this and that is the way I always set them up. I think the attached link where the concentricity of the neck bushings were checked and found to be the source of the issue is an eye opener.

http://bulletin.accurateshooter.com...ading-checking-the-geometry-of-neck-bushings/

 

[boltfluter]

I have seen several issues with bushings where the bottom or top of the bushing was not perpendicular with the bore. Also seen where the bushing stamping made the bushing not sit flat. Amazing how the manufacturers can screw up something as simple as a bushing.

Paul

 

[Texas10]

You don't mention what caliber you're loading for, but one of the Savages I have is a bolt gun in 223. I use the Lee collet die only. Never FL size, don't anneal and run-out is under .001 for over a dozen loadings. But I have other Lee collet dies that don't perform as well as this one does, just saying.

FWIW; my process is to de-capp after the range session, SS pin tumble, and neck size just before loading.

 

[ireload2]

The bushing lead in radius or chamfer may be too small. If the neck you are sizing is much larger than the bushing bore (say .006 or larger than the bushing hole) this can force the neck off center as it has to almost crumple to squeeze into the bushing. What you have is sort of the opposite effect of seating a flat base bullet in the case mouth with no chamfer in the case mouth. The case mouth has to jump a sharp corner.

This force permits the neck to be sized erratically.
Neck sizing bushings need about a 10 to 1 lead in angle that has a beginning diameter as large as the FIRED neck. You can easily see that if your case opens .006 when fired that your bushing needs at least .003 chamfer per side. This results in at least a .030 deep chamfer. (using the 10 to 1 ratio on each side)

Factory chambers are often too large in the neck to work really well unless you have a generous radius in your bushings and a long necked case . If you try another tool brand such as Neil Jones you will find much larger chamfers or radi on the bushing bores.

Modern cartridge design has reduced neck lengths a little too much sometimes. If you are loading a short neck round like a .243 or a 7mm Rem Mag and give the bushing a .050 long chamfer you do not have much neck being sized with some dies.
If you tend to use both sides of a tapered bushing hole both sides with need a lead in radius. If you have a coated bushing it may be tough to radius.

 

[Pvt.Donut]

All prep work done to the brass from fired to body sizing holds my runout at 0.001", then I neck size and measure 0.005-6" so it's definitely the neck sizing. Bushing is free floating, I usually size about 3/4 of the neck and verify the bushing is floating by shaking it as well. The only thing that fixes the issue is trimming each brass so the case mouth is flat. So I'm assuming through the firing and cleaning process, my case mouths deform from flat and that is influencing the bushing; causing one side of the mouth to contact the bushing first, canting the bushing and causing my issues.

I'll see if I can try some LE bushings to see if this helps, currently using Redding plain steel bushings. Might try using a FL RCBS die I have and a Sinclair expander to see if that helps.

 

[jonbearman]

I concur with Donavan , if it doesn't float and that chamber along with the plug isn't right there are problems. The Wilson bushings are a bit better. The Wilson hand dies work pretty darn good but I only have them for 6br and 6ppc. I wish that redding would do a better concentricity QC to alleviate some small issue's but I am dreaming. One thing I tried with my .260 bushing die was the o-ring but just leaving the die slightly loose did about the same at around .0015 - .002 so I just let it go for now. Every press is different too where my oldest rcbs rockchucker and junior do better than other presses I have had in the past so I stick with the oldie but goody presses,lol

 

[Shynloco]

With any bushing die, the bushing needs to free float in the bushing chamber. Seen it a couple times where either the bushing chamber needed polished out and/or the chamber cap tightened down to much restricting the bushings free movement. A dirty bushing chamber can also restrict free movement.
Each time before I put a bushing die into my press, I always shake it to assure the bushing is floating. I also clean the bushing chamber (and entire die) often.
Donovan

+1. I too found that you MUST make sure the inside of the neck die is clean and that the bushing is LOOSE and not restricted from "free floating." I've seen too many people tighten down the bushing with the stem and thereby causing exactly what the OP has encountered. I also use both the Redding S FL Die as well as the Redding S Neck Die and rarely, get a runout of more than .002 and that's from a bad piece of Lapua brass. Lastly, I've found it better to make sure no lube (like Resizing Wax) has gummed up the tight area of the die where the bushing sits. Like Donovan says, shake the die and make sure it rattles before screwing it into your press. I personally have experienced what happens when that simply procedures isn't used.

Alex

 

[Martin52]

Maybe the manufacturing tolerances are much tighter at LE Wilson, their neck die is designed with no float for the bushing.

 

[BoydAllen]

If you measure the thickness of non-carbide bushings between ID and OD, in several places with a neck mic., you will find that the hole is not in the middle. I have been told (by a gunsmith whose name is very well known in benchrest and F class) that if you mount them on a tapered mandrel that is between centers that their bores are not perpendicular to their faces. Measure the end of neck concentricity of a fired case that has not had its neck distorted by being banged inside of the action by an ejector and then compare it with a sized case. If your FL die is a bushing style, size a case without the bushing and another with the bushing, making sure that the bushing is able to float. I think that you will see a significant difference. IMO the straightest FL sized cases come from one piece dies that have neck IDs that were originally cut to the correct ID for the application. I have a Hornady one piece die for 6PPC that is an off the shelf item. It has a neck ID of about .258 which works with a powder like the LT series in a .262 neck chamber. The sized brass from that die has a concentricity measurement of about a third of a thousandth at the end of the neck. Die expanders can do a small amount of work without damaging concentricity. I helped a friend order a one piece Hornady custom FL die such that with the cases he uses the difference between using the expander and not is .001. Either way the concentricity is very good. Bushings are an easy way to play with neck tension, but they do not produce the straightest sized cases that are available. The question is whether the difference shows up on the target. If it doesn't, then it is irrelevant.

 

[X-Caveman]

Try necking down in two stages. No more than about .003" per time. You may even let the bushing float a LOT axially on the first pass. That will have the case better aligned when the neck enters the bushing.

 

[JRS]

The answer:

 

[NCVarhtr]

Follow Boyd's instructions above. He is absolutely correct. If you are seating your bullets "In the Lands" , you can get by with some runout. If you are "Off the Lands", then, concentricity becomes much more significant and important.