Excessive?

[_Raining]

Loaded Round = X
He asked for a die to size the neck down to X - .004
Then he uses a turning mandrel to push it back out to an end result of X - .002
He then fired a case and measured Y.
He noticed that Y - X - .004 = .011
His buddy said this was too much

This fired size can't be changed without re-chambering the current barrel or having a new blank chambered and installed. If he neck turns he could make some of that sizing up but it wouldn't be much. He could turn off 1 thou and switch to a bushing die which would reduce his sizing by 1 thou total but that isn't much.

New loaded size would be X - .001 = New X = X'
Y is the same and the bushing would reduce the need to use a mandrel so he could go straight to a bushing of X' - .002.
Y - X' -.002 = Y - X - .002 - .001 = .01

Taking off .0005 with neck turning would save him 1.5 thou
Taking off .0015 with neck turning would save him .5 thou

So his saving could be between 0 and 2.
He could save 2 thou if he uses a bushing die and no mandrel with no neck turning but chances are his walls are not uniform so this isn't a good idea.
And he could save 0 thou if he uses a bushing die and takes off 2 thou with neck turning. Taking off anything more than 2 thou would increase the amount the brass is worked.

 

[JFrank]

Forster Honed Dies (and less neck runout than a Redding bushing die)

No Kool-Aid and just served with common sense and the best beer in North America, since 1829.

I really don't care what your 6.5 buddy says, I have a bucket full of ruined brass from your expander ball, and a drawer full of dies that will never get used again.

This forum is full of people asking why their Forster did this or what's wrong with my Redding sizer.
I see it every day.
Take out the ball and tell me how much that brass is getting worked.
Im out

 

[Uncle Ed]

It might help if you learn how to adjust the Forster expanders and not ruin your brass.

I also installed the Forster expander assembly's on all my RCBS dies and Redding dies and do not ruin any cases.

And once the expander is adjusted correctly and you measure the neck runout vs using a expander die there is no sense in using a expander die and sizing the case twice.

There is also a reason why so many reloaders use a body die and a Lee collet die. And the reason is they get less neck runout than using a bushing die. But these same reloaders have not discovered the benefits of using Forster full length benchrest dies.

One of the biggest cause of case neck runout happens if the expander is locked down off center.

And even the cheap Lee full length die below has a locking collet that centers the expander in the die. And the Lee die is a good option for reloaders with factory rifles and no gauges to measure neck runout. Or reloaders who do not setup their Forster dies correctly and ruin their cases.

 

[Webster]

no expert, but wouldn't you want to measure a fired cases's neck O.D. and subtract the .004 thou to give the correct neck tension ? Given that the neck thickness is within a "normal" range of thickness, that should be what the op is looking for. If the difference between a fired case's id and the bullet diameter is really alot, then the chamber would be suspect....but please correct me if i am wrong, as i'm still learning at 63......rsbhunter

Reducing the neck diameter with a die then expanding it with a bullet both contribute cold working the brass. My FL die reduced the fired neck about 0.006". I now use a bushing die. Don't have all the numbers at hand.

 

[JFrank]

 

[Uncle Ed]

Something to cheer you up after a shooting match.

 

[Dusty Stevens]

If you turn the necks itll be even worse

 

[JFrank]

Loaded virgin Nosler brass in 270win with a 130 AB 18 mos ago. Measured the OD of the necks of loaded rounds, then ordered a FL sizer from Forster with the neck honed to .004” under (as they suggested). I then use an expander to get back 2 of those 4 thousandths before seating. Recently, I noticed that the difference between the OD of a fired case neck and a sized case neck is .011”.... a buddy says that’s crazy and I shouldn’t be moving brass that much... is he right? What could/should I do differently? Thanks

What is the difference in thousands between the OD of a loaded round and a fired round?

 

[Jody Simcox]

What is the difference in thousands between the OD of a loaded round and a fired round?

Loaded- .3025”
Fired- .3095”
FL sized- .2985”
Expanded- .3005”

 

[JFrank]

Loaded- .3025”
Fired- .3095”
FL sized- .2985”
Expanded- .3005”

.007 difference between loaded and fired.

Thanks for the clarification

 

[dcali]

Loaded virgin Nosler brass in 270win with a 130 AB 18 mos ago. Measured the OD of the necks of loaded rounds, then ordered a FL sizer from Forster with the neck honed to .004” under (as they suggested). I then use an expander to get back 2 of those 4 thousandths before seating. Recently, I noticed that the difference between the OD of a fired case neck and a sized case neck is .011”.... a buddy says that’s crazy and I shouldn’t be moving brass that much... is he right? What could/should I do differently? Thanks

Fired brass size is determined by the chamber neck diameter and nothing else. Neck tension is the difference between the ID of the sized brass and the bullet diameter. What you’ve learned is why we shoot tighter than SAAMI chambers.

Most of us aim for about .004 clearance between then loaded neck diameter and the chamber neck diameter. That means your brass will grow only about .003 on firing. You can then size it down .005 and wind up with .002 of neck tension.

Now if your chamber is allowing it to grow .011, that means you have about 12 thousandths of clearance (there is about .001 of spring back). You then have to size it down .013 to get your .002 of tension. That is just unnecessary brass working, which can contribute to runout and poor brass life.

 

[JFrank]

Fired brass size is determined by the chamber neck diameter and nothing else. Neck tension is the difference between the ID of the sized brass and the bullet diameter. What you’ve learned is why we shoot tighter than SAAMI chambers.

Most of us aim for about .004 clearance between then loaded neck diameter and the chamber neck diameter. That means your brass will grow only about .003 on firing. You can then size it down .005 and wind up with .002 of neck tension.

Now if your chamber is allowing it to grow .011, that means you have about 12 thousandths of clearance (there is about .001 of spring back). You then have to size it down .013 to get your .002 of tension. That is just unnecessary brass working, which can contribute to runout and poor brass life.

Jody
Has clarified his differences as .007 L-F

 

[_Raining]

If you turn the necks itll be even worse

How so?

His current configuration is:
Loaded- .3025”
Fired- .3095”
FL sized- .2985”
Expanded- .3005”
.3095” - .2985” = .011"

If he needs to turn off 1 thou to make the necks uniform then he can do the following:
Fired- .3095”
FL sized with bushing to - .2995”
Loaded- .3015”
.3095” - .2995” = .01"
It will expand 1 more thou on firing but 2 thou less during sizing.

The only way it wouldn't be better is if he needed to turn off 2 thou or more to achieve uniform necks.

Or am I missing something?

 

[Had2muchofForums]

If he makes the neck diameter smaller by neck turning, his brass will expand to the chamber wall that much more on each firing.

 

[_Raining]

If he makes the neck diameter smaller by neck turning, his brass will expand to the chamber wall that much more on each firing.

Yes, if he turns off 1 thou of his neck then it will expand 1 thou more BUT it will be sized 2 thou less during the sizing process bc he can use a bushing instead of sizing 2 thou extra then pushing it out with an expanding mandrel. The mandrel is only used bc the necks are not uniform so if you uniform them by turning then that step is not necessary.

It is only 1 thou difference but I don't understand the people saying it will make it worse.

 

[Dusty Stevens]

Yes, if he turns off 1 thou of his neck then it will expand 1 thou more BUT it will be sized 2 thou less during the sizing process bc he can use a bushing instead of sizing 2 thou extra then pushing it out with an expanding mandrel. The mandrel is only used bc the necks are not uniform so if you uniform them by turning then that step is not necessary.

It is only 1 thou difference but I don't understand the people saying it will make it worse.

If the brass expands .001 more upon firing thats worse than not. Id rather cold work it more than blast it out more

 

[_Raining]

If the brass expands .001 more upon firing thats worse than not. Id rather cold work it more than blast it out more

Interesting, do you know of any articles that go over the differences between working the brass under fire and working it with a reloading die?

 

[Dusty Stevens]

Interesting, do you know of any articles that go over the differences between working the brass under fire and working it with a reloading die?

No i dont. I just go by what i see.

 

[JFrank]

How so?

His current configuration is:
Loaded- .3025”
Fired- .3095”
FL sized- .2985”
Expanded- .3005”
.3095” - .2985” = .011"

If he needs to turn off 1 thou to make the necks uniform then he can do the following:
Fired- .3095”
FL sized with bushing to - .2995”
Loaded- .3015”
.3095” - .2995” = .01"
It will expand 1 more thou on firing but 2 thou less during sizing.

The only way it wouldn't be better is if he needed to turn off 2 thou or more to achieve uniform necks.

Or am I missing something?

Loaded to fired is .007 not .011

 

[_Raining]

Loaded to fired is .007 not .011

Yes I am aware.
I looked over my math once more and figured out where my logic was flawed. I should have done the combination of fired expansion and reloading sizing.

So a round trip for his current configuration is:
.007 + .011 = .018

For 1 thou turned off it is:
.008 + .010 = .018

For .5 thou turned off it is:
.0075 + .0095 = .017

So the only way to save working the brass is by using a bushing and turning off 0 up to but not including 1 thou, which would produce:
.016 up to but not including .018

As for rather having the brass worked less under fire than sizing, I have no opinion on this matter as I have no experience with it nor do I have any sources of tests done to determine the effects.