Neck Turning Once Fired Brass ?

[Chubbs]

If I resize my brass using a Neck Bushing F/L resizing die it only resizes 9/10 of the neck. The first 9/10's being 20 Thou smaller than the last 1/10.


So if I neck turn to the shoulder it will trim off an extra 20 thou making the neck wall thickness uneven. Should I not use a neck bushing die until I have turned the necks. I have a Lee F/L die which will obviously size the case different, but as I want to do load development should I also wait until the 2nd firing ?

 

[Preacher]

Not a problem, the bushing needs a ledge to set on.
if they need turning do it before you size them...

 

[AlNyhus]

Your dimensions (if correct) are wonky.

Assuming they are correctly measured with an accurate micrometer (not a dial caliper), you're looking at a difference of two thousandths (.002), not .020 which is twenty thousandths.

Make sure the bushing isn't tight in the die...it needs to float or you can see this issue. Also, try flipping the bushing over and see how much it contacts. -Al

 

[243winxb]

I fl size in standard die. Then neck turn. Cant use my bushing die, because it does not size all the way to the shoulder.
Next loading, use the bushing die.
Tip: Size only 1/2 of the neck.

 

[PopCharlie]

Some shooters like to size all but the last bit of the neck. Usually the last 25% of the neck is unsized by the bushing. Make sure your bushing is not floating too much. Also, turning the necks after 1 firing is not bad. Just make sure you turn far enough down the neck to blend in to the shoulder and make them even thickness. You should also turn them again after firing them an additional 3 to 4 times.

PopCharlie

 

[47WillysGuy]

If I resize my brass using a Neck Bushing F/L resizing die it only resizes 9/10 of the neck. The first 9/10's being 20 Thou smaller than the last 1/10.
View attachment 1220690

So if I neck turn to the shoulder it will trim off an extra 20 thou making the neck wall thickness uneven. Should I not use a neck bushing die until I have turned the necks. I have a Lee F/L die which will obviously size the case different, but as I want to do load development should I also wait until the 2nd firing ?

Do NOT use a bushing die to prep your cases for neck turning. When firing you may blow the neck off the case. Use a die that sizes the neck to the shoulder.

After neck sizing, mandrel the case neck to a diameter about 0.001" larger than your cutting mandrel. That keeps the heat down. Cut all the way to just touching the shoulder.

The expanding mandrel will pushes excess neck brass to the outside and the cutter will take that excess off plus to whatever you want your wall thickness to be. Play with expendable brass until your ready to work the good stuff. Can't put it back on.. Good luck.

 

[Capt45]

I fl size in standard die. Then neck turn. Cant use my bushing die, because it does not size all the way to the shoulder.
Next loading, use the bushing die.
Tip: Size only 1/2 of the neck.

Why just 1/2 the neck?

 

[Chubbs]

Thanks for the advice guys.
AINyus you are right I did mean 2 thou. Good Spot.
Looks like I need to use the standard F/L die first. Hopefully this will not change the internal volume so as to make a significant change in the load development. I think the Lee die compresses the case body more.
So it will be 1 x Fired case - F/L die - Expander mandrel - trim case - neck turn.

 

[mikecr]

I doubt you'll get a good turn* after FL sizing of fired necks.
Should turn while cases are new, using only expansion provided by the turning system mandrel.
With this, you turn a touch into neck-shoulder junction, and when you fire this junction snaps outward to become part of a donut free neck.

When you fired necks first, you created donuts that you'll have to deal with, and nobody has ever countered donuts with FL sizing (just opposite). Now, fired and formed with donuts your necks will not size & spring back & turning mandrel fit the same as they do when brand new/right out of the box.
Neck contact with the turning mandrel will be at the smallest IDs (donut & mouth) leaving gaps mid-neck between neck and mandrel. Then after turning, if you measure your neck thickness at 3 datums along neck length, you'll likely see 3 different thicknesses.
It won't be tragic,, still good enough for most, but not the best.

*My Opinion

 

[Ccrider]

There are different views on this. Some very experienced shooters turn twice. I think that consistency in neck thickness is what matters, specifically where the neck is holding the bullet. The unsized portion behind the part holding the bullet seems not to matter as much. Some say donuts in that area don’t matter, others say that they use that area to help center the case into the chamber and actually use two bushings to accomplish this. Still others size and return the entire neck. My goal is to get each pice of brass exactly the same size in all respects. Easier said than done.

 

[jackieschmidt]

Here is the major problem.
When you fire a case, the neck comes out about the same size as the chamber’s neck, minus a tad of springback. Depending on the chamber’s neck diameter, this could be as much as .005 larger than a loaded round.
When you close the neck down with a bushing die, that portion that the bushing does not close will still be large. When you run the now neck sized case over your expander to be used with the neck turner, it probably will not even hit this oversized inside.
When you turn the necks down to the neck shoulder junction, you will now have a thin spot in the neck near the neck shoulder junction.
The best way to solve this problem is run your cases in a standard die with the expander pluc removed. That will make the neck with a consistent OD. Then, you can expand to fit your neck turner.

 

[BoydAllen]

Expand one of your sized cases and remeasure the difference. It may be reduced from the .002 that you are now seeing. If it is, the unsized portion of the neck will be thinner by half of the difference (between the ODs of the sized and unsized parts of the expanded neck), which may or may not matter. I would do a few, and then load and shoot them a few times to see if there is a functional problem.

 

[Ccrider]

Here is the major problem.
When you fire a case, the neck comes out about the same size as the chamber’s neck, minus a tad of springback. Depending on the chamber’s neck diameter, this could be as much as .005 larger than a loaded round.
When you close the neck down with a bushing die, that portion that the bushing does not close will still be large. When you run the now neck sized case over your expander to be used with the neck turner, it probably will not even hit this oversized inside.
When you turn the necks down to the neck shoulder junction, you will now have a thin spot in the neck near the neck shoulder junction.
The best way to solve this problem is run your cases in a standard die with the expander pluc removed. That will make the neck with a consistent OD. Then, you can expand to fit your neck turner.

Thanks for explaining this Jackie. It all makes since now.

 

[243winxb]

Why just 1/2 the neck?

It centers the round in a factory chamber.

 

[Fotheringill]

BTW- Redding bushing dies and neck sizer are not designed to go down to the shoulder. Call Redding to verify what I am saying, please.

You can get it down about 2/3-3/4 by using the adjustment on the top of the die. The dies are also interchangeable with several other manufacturers' dies. I know definitely RCBS but the brands of the others escape me.

 

[Chubbs]

Thanks again guys for the replies.
I have now run some cases through the standard F/L die and trimmed the necks to the shoulder. I will fire theses and then resize using the bushing die. Just need to get to the range and test them.

 

[Chubbs]

Tested the 1 x fired and then F/L sized and neck trimmed cases. All seems fine.

 

[searcher]

I turn the necks on almost all my brass - and a fair amount of it is thousands of once-fired Lake City brass for use in my .20 Practical and .223. The best method I have found to getting uniform necks is to first size with whatever die you have (I use a Redding full-length short-base die) just to get the neck in line, then anneal to soften the neck, then run through an expander MANDREL that REALLY opens them up. Then I turn them on a mandrel that is .001" smaller than my expander. In measuring with a ball micrometer, I find little issue with thin spots near the shoulder junction. In reading prior posts, I have no idea of how one could get a doughnut by turning into the shoulder. You get doughnuts by not turning that area. If anything, a thin spot would occur if you are turning off a bulge if you did not first run an oversized mandrel through to iron the neck out. As for "blowing necks off", you would have to take off so much material that your necks would probably be suspect even without the resulting thin spot. Even so - a ball micrometer will enable you to measure your thicknesses to be sure you haven't taken off too much. Most folks aren't taking off more than to "clean metal". If you end up taking off another .001" in process of going all the way to shoulder - that is harmless. In fact, it will help to stave off doughnuts caused by the flowing of brass forward to the neck. Yes - the brass will be a bit thinner there - but your micrometer will show you how much. While I don't do it on my A/R brass, I am a big believer of doing a second skim turn after two or three firings - and that will be it for the life of the brass. It takes that second turn to get the wrinkles out that the first can't until the brass is fired - as is very evident when watching the material come off.