Neck Bushing Causing .002 additional Run-Out

['Freak]

He is asking about run out . A floating bushing can cause run out . Any difference Chamfer in the out or inside of the neck let's the bushing move and it will seek the areas of the lease resistance . Larry

Agreed on gotta leave room for the bushing to float.

And, yup, if so be the case, I do see it reported that trying to knock down a neck diameter that’s say possibly more than five or so thousandths greater than the bushing ID, and doing it all in one whack, can negatively impact neck concentricity.

 

[pete1955]

At the Whidden custom die website they tell you they get the most concentric ammunition from their non-bushing full length dies. They also sell expander kits with five expanders in .001 increments

As stated above a bushing die can create neck runout. It becomes worse if you reduce the neck diameter .005 or more. And why you are told to reduce the diameter the neck in two steps if the bushing is reducing the neck diameter .005 or more.

And I remember amlevin saying here the only way he could reduce neck runout on some of his cases was to use a Forster full length die. And I can confirm that and also the Forster full length die will even straighten the neck of the case.

 

[foxguy]

Just a little further info on what I am trying to accomplish. I shoot in Fun Matches 200 & 300 yds currently.
the club I belong to is looking to extending a Range out to Possibly 600 yds for some friendly local competition.

I currently shoot against some 6 PPC's and am looking for a rifle that will hang with them in our local competitions. I purchased the Savage 6MM BR and am working to identify the loads that will produce the smallest groups so I have a Chance to keep them on their toes. Its all in Serious Fun!

 

[foxguy]

Agreed on gotta leave room for the bushing to float.

And, yup, if so be the case, I do see it reported that trying to knock down a neck diameter that’s say possibly more than five or so thousandths greater than the bushing ID, and doing it all in one whack, can negatively impact neck concentricity.

I just went an looked in my records and found I didn't write the Fired Brass neck size down.
I am using laupa 6MM BR Brass, Barnes 68 gr bullets and I am 80% sure the fired neck size is .270 OD (loaded rounds are measuring .268-.2685).

Again, Fired Brass neck sized with a .267 bushing has a .0005 runout, I have check this on 5 resized cases and at that point I thought it was pretty consistant.

I will clean the die and bushing and try the .266 bushing on a case that has been .267 neck sized. I will measure the run-out of the .267 resized case before and then after sizing with the .266 bushing to verify the Run-out is related to the .266 bushing.

thanks- this is a good Idea and is easy to do.

 

[John Russell]

I have a new 6MM BR that I am Loading for. My hopes are that I can I can reloaded ammo that can shoot Appx 1/2 MOA groups at 200-300 yds. I have purchased 3- bushings .266,.267, & .268.
(My loaded rounds are measuring .268-.2685 at the neck.

Bushings causing additional neck sized run-out
My Fired Brass has .0005 run-out before neck sizing. When using the .267 Neck sizing Bushing it adds another .0005 (.001 runout, I think that was pretty good), My Problem is when using the .266 bushing it adds another .002 thousands (.0025) to the Sized Brass Neck Run-out.

I haven't reloaded enough to know if this will be a big problem in trying to get loaded rounds with low run-out and producing very accurate ammo?

Should I be looking to replace this .266 neck bushing and hope for better one? My bushing and sizing die are made by the same manufacture.

Thanks, I appreciate hearing from those who have experience with this.

Why didn't you say what die it is - Redding, Forster, RCBS, Whidden... other??

And is it a bushing neck sizer, a bushing FL sizer, or a bushing comp sizer?

Each one works differently, and that makes a difference in how to evaluate the problem and (hopefully) find a solution.

For example, in a bushing neck sizer, it makes no difference if the bushing is in tight or loose since the die doesn't guide or support the case in any way... the die could have a 0.6" hole for a chamber for that matter... or you could use a 22-250 bushing neck sizer to size a 222 mag case - since the case has no contact with the die body, it would make no difference in the outcome

In a FL bushing die, the case body is held in axial alignment when the neck enters the bushing section, so the bushing needs to be able to float and center itself as the neck is pushed into it.

With the comp bushing sizer, it makes a big difference. The case is forced into axial alignment by the cone of the case shoulder, against the cone of the die chamber, then the bushing is brought down on the case neck.

I have tried all three and I have found that the comp sizer works best - my run-out on sized cases from a .220 Swift (whose chamber has a very large neck) is under 0.001"... the neck gets sized ~8 thou in one pass and comes out coaxially concentric.

 

[pete1955]

Mr. Russel

Does this mean the bushing in the competition die does not float and have as much play as a standard bushing die?

And if your wife finds out how much the die costs, what should you do to keep from ending up singing in the Vienna Boys Choir.

I gots to know...........

 

[foxguy]

Ok,

Here is a follow up on some of the Ideas suggested here.

I Cleaned the Die and .266 Bushings and installed the .266 bushing with the numbers down (same as before).

I re measured the run-out on 3 pieces of the.267 bushing Neck Sized brass confirming it had .001 of run-out.
Next I resized 3 pieces on the brass that had previously been Neck sized with the .267 Bushing. After re sizing with the .266 neck bushing I measured the neck run-out again, it now measures having .0015 of run out. I'm a lot happier with 0.0015 thousands run-out measured on the neck than 0.0025 measured in the same place.

As Donavon suggested I cleaned both the die and bushing(when I sized the fired cases originally with the .266 neck bushing I didn't clean the die, I just removed the .267 bushing ( as I had only neck sized 50 cases and thought it had looked ok) and inserted the .266 bushing adjusted for just slight looseness and began sizing.

It now appears that

1. the Die may of been dirty, I don't know?? possibly a piece of something in the wrong place when I inserted the .266 bushing)
moral I need to clean the die and Bushing every time before Re-Sizing.

or

2. Resizing from a neck size of .270 down to .266 is causing additional run-out. I am using a Redding Neck Sizing Die and Possible a Redding FL Neck Sizing Die would help to solve the additional run-out that the neck sizing die may be helping to cause??

As I had shared earlier, I am new to Neck Sizing and learning new stuff all the time.

John,

I am using the Redding Neck Sizing Die and a Redding Titanium coated Bushing , I thought as I had sized with the Die and .267 bushing and only had an addition of .0005 in run-out that I was good to go. (I didn't want to throw mud towards the Redding Product name). I had read in the last week or so that Neck Bushing could cause Run-Out and it looked like that was what I was seeing. Based on that, I thought I would come on this sight and ask the question and see what others thought. I don't know for sure but it looks like when I run the brass up into the Neck Sizing Die the brass Shoulder does bottom out in the die and at that time the case is captured between the shell holder and the die shoulder cut out and then the case neck is run up into the bushing.

It does look like the .266 bushing did add a little more run out, but the fact that I didn't clean the die and bushing possibly contributed more that the bushing change??

The next time I go out and Shoot I will bring home some fired cases (.270 fired neck size), clean them up( 0000 steel wool the out side of the Necks), deprime with out the Neck Bushing installed, Brush the inside of the necks to clean up loose carbon, install the .266 bushing in the cleaned up die, lube the necks and resize them again, followed by measuring the run-out.

Thanks- still learing

 

[mikecr]

Your runout numbers are not out of ordinary given the very beginning of awareness and efforts to improve it.
I doubt it's any kind of bushing or die issue.
It's most likely brass thickness variance, and the more you size this the greater your runout result in doing so.

 

[Cool Tool]

My suggestions:
- Assure that the .266 bushing is "floating" in the die (and all other bushings as well).
- Assure that the bushing chamber in the die is clean (I also polish the bushing chambers).
- If these things check out, then I would contact the mfg and see about getting the .266 replaced.
Good Luck
Donovan

I hope this question does not rub anyone the wrong way but I get the impression that .002 runout is not acceptable if I am reading this right.

 

[John Russell]

The comp

Mr. Russel

Does this mean the bushing in the competition die does not float and have as much play as a standard bushing die?

And if your wife finds out how much the die costs, what should you do to keep from ending up singing in the Vienna Boys Choir.

I gots to know...........

I thought the price on the comp sizers was outrageous too - I mean who needs a flippin' micrometer adjustment on a neck sizer. But when I got my 6mmBR bench rest riffle, I bought the full set of Redding Comp dies, which was a comp neck sizer, body die, and comp seater... because that was what they had in stock at the time, and like a little kid at Christmas, I didn't want to wait for the separate dies to come in (who knows when).

When I looked at the comp neck sizer, it all made sense.

The comp bushing neck sizer is like the comp seater - the case is in a floating sleeve and locked in place. I do not know how much play the bushing has in it's own chamber. The bushing is 0.500", I do not know if the bushing chambers are 0.501, 0.503... or whatever - I do know that they work very well, and I am replacing my Bushing "S" dies with comps, as the money becomes available.

I will confess that I modify all of my bushings when I get them.

As to the wifie... back some time ago, she said, "If you buy one more gun, I am leaving you."

It was fully 7 or 8 weeks of quiet before I realized that she meant it, and had moved out to live with her mother. It is so peaceful now. I get to have bacon cheeseburgers for breakfast on the weekends, and I don't have to have a mother-in-law telling me that I should stop killing poor widdle woodchucks.

 

[pete1955]

I hope this question does not rub anyone the wrong way but I get the impression that .002 runout is not acceptable if I am reading this right.

The military considers .003 or below match grade ammunition. When the case is full length resized it is support by the bolt face in the rear and by the bullet in the throat. And the body of the case and the neck never touch the chamber walls and should not have any guiding effect on the bullet. Meaning the shoulder of the case is all that contacts the chamber, when pushed forward by the ejector or firing pin. A resized case is approximately .003 to .005 smaller in diameter than the chamber.

 

[Cool Tool]

The military considers .003 or below match grade ammunition. When the case is full length resized it is support by the bolt face in the rear and by the bullet in the throat. And the body of the case and the neck never touch the chamber walls and should not have any guiding effect on the bullet. Meaning the shoulder of the case is all that contacts the chamber, when pushed forward by the ejector or firing pin. A resized case is approximately .003 to .005 smaller in diameter than the chamber.

Ok in other words you are saying no worse than .002 is acceptable.

 

[dmoran]

I hope this question does not rub anyone the wrong way but I get the impression that .002 runout is not acceptable if I am reading this right.

Personally I don't know if +.002 is unacceptable, just know that mine don't have that much or I find the issue and address it. A 1/2-thousandths max over spent case measures is acceptable to my own desires. Figure its is my job to produce concentric handloads, so the rifles don't have to tell me what is an acceptable amount.
Donovan

 

[John Russell]

The military considers .003 or below match grade ammunition. When the case is full length resized it is support by the bolt face in the rear and by the bullet in the throat. And the body of the case and the neck never touch the chamber walls and should not have any guiding effect on the bullet. Meaning the shoulder of the case is all that contacts the chamber, when pushed forward by the ejector or firing pin. A resized case is approximately .003 to .005 smaller in diameter than the chamber.

This is a hotly contested subject, and I will not fight about it... but:

Short range bench guys FL size cases because they shoot free recoil and cannot have to deal with torquing and displacing the rifle in the sandbags when closing the bolt.

But I don't shoot PB bench anymore - it died in my part of the country a long time back - none of my shooting friends shoot PB bench anymore either... so I do not FL size my cases - I adjust my dies so the case has some resistance when closing the bolt - enough, so if you strip the bolt, the bolt handle will drop about 1/3 to 1/2 way down on a loaded case. This is pretty much accepted practice for many accuracy shooters.

I use Forster bump dies with Redding comp shell holders when I have to nudge the shoulders - it is easy peasy, and completely repeatable.

With calibres that Forster does not make bump dies for, I measure the headspace in a standard bushing "S" die with a real headspace gauge, and calculate how much I need to take off. Then I have a local machinist cut that much off of the bottom of the die off with a carbide cutter - and "poofie" an instant Redding "Bump" die

 

[Cool Tool]

Personally I don't know if +.002 is unacceptable, just know that mine don't have that much or I find the issue and address it. A 1/2-thousandths over spent case dimensions is acceptable to my own desires. Figure its is my job to produce concentric handloads, so the rifles don't have to tell me what is an acceptable amount.
Donovan

Okay

 

[pete1955]

Ok in other words you are saying no worse than .002 is acceptable.

No, to be match grade ammo the military states that .003 runout or "less" is considered match grade.

Meaning .003 runout is the maximum allowable to be match grade ammo.

 

[pete1955]

With calibres that Forster does not make bump dies for, I measure the headspace in a standard bushing "S" die with a real headspace gauge, and calculate how much I need to take off. Then I have a local machinist cut that much off of the bottom of the die off with a carbide cutter - and "poofie" an instant Redding "Bump" die

Whidden sizing dies are made shorter and there is a warning to not run the die down to touch the shell holder. Just in case your paying the machinist and want to weigh the cost factor.

In another forum a person sized 200 new Lapua cases and found out all of these cases were ruined.

http://www.whiddengunworks.com/wp-content/uploads/2014/08/Sizer-die-warning-statement.pdf

WARNING
Failure to adhere with below warning could result in damaged and unsafe brass!

The Whidden Gunworks Sizer Die is engineered with a shorter overall length (OAL) compared to other manufactures
of sizer dies. This means you can set the shoulder back further if desired based on your specific application. This die is not
intended to be used while bottomed out or screwed flush with the shell plate.
.

 

[John Russell]

Same thing

Whidden sizing dies are made shorter and there is a warning to not run the die down to touch the shell holder. Just in case your paying the machinist and want to weigh the cost factor.

In another forum a person sized 200 new Lapua cases and found out all of these cases were ruined.

http://www.whiddengunworks.com/wp-content/uploads/2014/08/Sizer-die-warning-statement.pdf

WARNING
Failure to adhere with below warning could result in damaged and unsafe brass!

The Whidden Gunworks Sizer Die is engineered with a shorter overall length (OAL) compared to other manufactures
of sizer dies. This means you can set the shoulder back further if desired based on your specific application. This die is not
intended to be used while bottomed out or screwed flush with the shell plate.
.

Same thing for the Forster bump dies - they are made ~4 thou shorter than SAAMI minimum for guys that have very short chambers - by the time you are using these kinda dies, it is expected that you know how to set up a sizing die, and not just "Screw it down".

 

[foxguy]

Your runout numbers are not out of ordinary given the very beginning of awareness and efforts to improve it.
I doubt it's any kind of bushing or die issue.
It's most likely brass thickness variance, and the more you size this the greater your runout result in doing so.

Mikecr,

So if I understand this correctly, As I continue resizing my Fired Brass even with the .267 neck bushing which was giving me .001 run-out variance, the more times I fired and then resized, the run-out would progressively get worse? This makes me have to ask........ How do you correct it? Would the Redding Competition Neck Sizing Die help to correct this?

 

[pete1955]

Mikecr,

So if I understand this correctly, As I continue resizing my Fired Brass even with the .267 neck bushing which was giving me .001 run-out variance, the more times I fired and then resized, the run-out would progressively get worse? This makes me have to ask........ How do you correct it? Would the Redding Competition Neck Sizing Die help to correct this?

You full length resize the case using a Forster full length benchrest die. The Forster die has a high mounted floating expander and the case neck is held and centered in the die when the expander enters the case neck.

This die will even straighten the necks that have excess neck runout.

In post #22 I even stated that a old member here by the name amlevin said the same thing about straightening the necks with the Forster FL die.