Sizing and Neck Turning

[cobbonthecorn]

As my quest for accuracy continues I have read contradicting pieces on sizing and neck turning. I hope someone can help sort my questions.

I have a set of Redding S dies, body, bushing neck, and seating. I have been told to full length size every 4th or 5th firing. If true I will need to get a full size die. Is this true? If true, why does the body die not fit the bill?

For neck turning K&M offers cutting and non-cutting pilots. Should I get both? When is one or the other used?

Thanks in advance!

 

[284driver]

The k and m cutting mandrel cuts the doughnut. The standard pilot does not. If you have doughnuts get the carbide cutting mandrel.

 

[cobbonthecorn]

Thanks for both sets of input.

 

[rocketron]

if you are going to neck turn fired brass. you will need a FL die. a bushing will not size to the neck shoulder junction.

 

[Shynloco]

if you are going to neck turn fired brass. you will need a FL die. a bushing will not size to the neck shoulder junction.

Sorry to disagree, but as Donovan says, if you have a Body Die, it'll do what you need, except you'll have two steps instead of one that an FL Die does in one. I have both Body Dies and FL Dies for all my calibers and sometimes I use a Body Die and a Neck or Bushing die before turning necks and other times I use only the FL Die or FL Bushing Die. What I use as the deciding factor as to which die I'll use depends on the run out of the casings after it's been fired. I've found that a Body Die actually gives me a better and tighter body resizing (than an FL Die) and if I have a borderline or "squirrlie" casing and I'll use the Body Die in an attempt to rehabilitate it AFTER I anneal that casing. or casings.

 

[lrgoodger]

You can go ahead and turn bushing sized necks and probably never see any ill effects from it, but you will wind up with a band at the base of the neck that is thinner than the rest of the neck. That is because, as rocketron said, the bushing does not size all the way to the junction. So, when you start turning, the cutter gets down to that section of neck that has not been squeezed back in by the bushing and cuts it to the same OUTSIDE diameter as the rest of the neck. The INSIDE diameter at the base of the neck is larger because the bushing did not squeeze it back in, so you wind up with a thin area of neck at the base.

That's why I don't turn fired brass unless is has been resized with a full length sizer.

Hmmmm. You might never have to worry about donuts doing it that way, though.

 

[Joe Maisto]

You can go ahead and turn bushing sized necks and probably never see any ill effects from it, but you will wind up with a band at the base of the neck that is thinner than the rest of the neck. That is because, as rocketron said, the bushing does not size all the way to the junction. So, when you start turning, the cutter gets down to that section of neck that has not been squeezed back in by the bushing and cuts it to the same OUTSIDE diameter as the rest of the neck. The INSIDE diameter at the base of the neck is larger because the bushing did not squeeze it back in, so you wind up with a thin area of neck at the base.

LR;

On that same topic, a point of interest about so called "donuts".
I shoot a PPC at short range benchrest, which requires us to take a new Lapua .220 Russian case and change it dramatically. When we are done, the shoulder is blown out to 30 degrees with very little taper to the case.

That said, before I knew what I do now, I had donuts when others didn't. I finally found out why, ( and that was recently ) I was NOT using a body die to bump the shoulder BEFORE I began turning necks. When this is done, the donut no longer becomes an issue.

Here's another one I just now found out, as I am in the process of turning necks today. Right out of the box...the new brass does not all measure the same. OAL can and does vary by .002-.003. Upon examining my turned necks with a magnifying glass, it was obvious the 30 degree angle cutter was just a tad deeper on the shoulder than some others. There you have the reason why. In other words.....It is my belief that one needs to remove that small difference in a case trimmer. When that happens, the cut INTO the shoulder will be exactly the same for all cases, because the case bottoms out on most neck turners, as it does on my Nielsen turner. It may not mean a great deal, however, I for one do not want to see a "ridge" on my shoulders from cutting too deep, which is what takes place if a particular case is .003 longer than another.
I do not foresee anymore "donuts" in the future.

The body die, will fit the bill...... It will resize the case body and bump the shoulder (like a F/L), but not the neck.
Then with your neck die, you size the neck, (after the body-die step). Two separate steps.....

 

[cobbonthecorn]

Now I know why I'm so confused. If I read the input so far, body and bushing neck die can result in neck thinning because the neck-shoulder junction does not get sized down, and the other point of view is using a full length die will uniformly reduce the neck even at the shoulder but may cause donuts. Right?

On the subject of donuts. I have made the assumption that we are talking about rings interior to the neck that cause unequal pressure if/when a bullet is seated deep enough to engage the donut. In that case, in my original question, the K&M cutter-pilot should cut the donut away. Right?

 

[Lbart]

[On the subject of donuts. I have made the assumption that we are talking about rings interior to the neck that cause unequal pressure if/when a bullet is seated deep enough to engage the donut. In that case, in my original question, the K&M cutter-pilot should cut the donut away. Right?
[/quote]
Yes! I use one on everyone of my cases.
Larry Bartholome

 

[TimP]

IMO you are better off FL sizing your brass if you are going to turn your necks. I am not saying it can't be done after you neck size with a bushing die but like other have said you will end up with a thin area at the base of the neck.

If this is fired brass set your FL die to bump the shoulder back .002 - .003 this way you will not overly change the brass dimensions. The FL die will resize the neck right down to the shoulder and all the shoulder neck junction will be consistent case to case. (This may require annealing depending on how many times the cases have been fired.) Trim all of you cases and your cut depth into the shoulder will be the same case to case.

 

[bigedp51]

Why would you use a bushing die and push defects to the inside of the neck when it is recommended to "expand" the necks prier to turning?

That is like balancing your car rims before you mount the tires.

Complete Precision Case Prep
http://www.accurateshooter.com/featured/complete-precision-case-prep/

Neck Turning Basics
Turning Cartridge Brass Necks for High Power Shooters
by German A. Salazar

Brass Preparation
Before we go any further, size your brass with a full-length non-bushing die and trim to uniform length. Both these tasks are VERY important. If the brass is new, run it over the expander and trim to uniform length. While I don't like non-bushing dies for regular case sizing, this is where they are important. For neck-turning, you have to size the neck all the way to the shoulder junction and a bushing die always leaves about 0.050" unsized (by design, you can't fix that). If all you have are bushing dies, I recommend the Hornady New Dimension as your non-bushing die, they are well made and leave the brass very concentric.

http://www.6mmbr.com/neckturningbasics.html

 

[yukonal]

Thanks for the links biged. Saved 'em for future reference.

 

[SS427]

Limited experience here, so take if for what it is worth. When I turn necks, I first run an expanding mandrel (from the manufacturer as my neck turner) down the necks. Then I trim so all cases are exactly the same length. If a few cases are way shorter I set those aside and deal with them separately. Then I turn the necks. This way all cases are cut into the shoulder exactly the same amount.

Recently I had to neck down some 22 caliber cases to 20 caliber and all I had was a FL bushing die. That left a slight bulge at the base of the neck as describe by others. I couldn't get the cases to chamber, so I set up the die to slightly cam over and that reduced the bulge enough to chamber, but there was still a slight bulge. I turned the necks into that bulge, however I was only taking about .001 off to uniform the necks, so no big deal to me. However if I was taking off much more brass, I would us a FL non-bushing die in a similar necking down situation. I don't think I would want such a thin section at the base of my necks.

As for the cutting versus non-cutting pilot I don't see a reason to buy a non-cutting pilot. If you don't have anything to cut, so what. But if there is a donut there, makes sense to have the cutting pilot. I don't see any downside to the cutting pilot since they are the same price, at least from K&M. Or am I missing something?

 

[cobbonthecorn]

I appreciate the inputs. Lots to comprehend and sort through. I must say there really isn't consensus on full or body die anywhere. The two articles referenced above are what got me to ask the question since one article say to use a FL die and the other says to use either a FL or body die. Any and all input is being considered. Thanks!

 

[queen_stick]

not trying to make an argument for or against either method, but here's my experience with both:

I started out using the neck-size only method. Of course, every couple of firings, I would use the body die to bump shoulders and size the base. This method didn't work out for my situation, since I was using hot loads in a 6BR for 1K BR shooting. After a single firing (and neck sizing only) I had some cases that would have stiff extraction and some that wouldn't. Keeping track of brass that sticks, brass that doesn't, brass that's 2x fired, brass that's 3x fired, brass that's freshly body sized/bumped, Brass that's 5x fired but only body sized once vs 5x fired and body sized twice, and etc... get's old fast! Because the base of the case wasn't being resized, some of my cases were sticking in the chamber on the 2nd firing (bolt click/pop sucks). This problem was greatly reduced (almost mitigated) when I changed over to FL sizing after every firing. I'll never go back neck sizing only, even if I run loads that don't beat up the brass.

 

[Joe Maisto]

Otter;
What you have stated is true. I am in the process of turning 100 Lapua PPC. and find that if out of the box brass varies by .002-.003 in length, ( and they do) the cut into the shoulder will vary. ( as I found out today). If you go through them and find the long ones, trim them to the length of the shorter ones. Now, (as you say) the shoulder cut will be the same on all of them.

Good point you brought up !

Joe

 

[Joe Maisto]

not trying to make an argument for or against either method, but here's my experience with both:

I started out using the neck-size only method. Of course, every couple of firings, I would use the body die to bump shoulders and size the base. This method didn't work out for my situation, since I was using hot loads in a 6BR for 1K BR shooting. After a single firing (and neck sizing only) I had some cases that would have stiff extraction and some that wouldn't. Keeping track of brass that sticks, brass that doesn't, brass that's 2x fired, brass that's 3x fired, brass that's freshly body sized/bumped, Brass that's 5x fired but only body sized once vs 5x fired and body sized twice, and etc... get's old fast! Because the base of the case wasn't being resized, some of my cases were sticking in the chamber on the 2nd firing (bolt click/pop sucks). This problem was greatly reduced (almost mitigated) when I changed over to FL sizing after every firing. I'll never go back neck sizing only, even if I run loads that don't beat up the brass.
[/quote

Well done !
Keeping brass seperated as you have stated is a chore. I do shoot with a guy in MI. that has it figured out. He has 4-5 bunches of cases ( equally), and puts them in their appropiate container after each firing. He has as many as 100 cases seperated, ( more than I want to mess with)