Bullet run out how much matters?

[muleman69]

We were messing around in my shop tonight and thought we would run a concentricity test. Took two pieces of the very same brass that had been neck turned and fired the same amount of times and ran one in the Redding f/l sizer and the other in the lee collet die then ran them on my Sinclair concentricity gauge. Both came out right at .001. The only differents we could see is the Lee is only $30

 

[dolek]

I removed the expander ball from a Forster Die because I was fed up with stretching the brass neck back and forth followed by constant trimming, only to discover my Die would reduce the necks almost.010 - E Gads!
I could have sent the Die to Forster for honing but opted for a different path.

Expander ball was not there to do it's job,what did you expect ? Something has to give it uniform dimensions...expander ball or a mandrel afterwords .

 

[Bart B.]

I removed the expander ball from a Forster Die because I was fed up with stretching the brass neck back and forth followed by constant trimming, only to discover my Die would reduce the necks almost.010 - E Gads!

Forster makes those dies to size a big range of neck wall dimensions.

 

[Ccrider]

I have found that runout is consistent in each casefeom one firing to the next. If a particular case has .001 runout, it stays the same from load to load. Same of it is .003.

With my 6mm ammo, I have not seen runout over .003. I don’t think this is enough to matter at short range.

With my 257stw ammo, I see higher runout. I had not been neck turning this ammo but will start to see if that reduces the runout. I fullexpect that it will since that ammo is necked down from 7mm. I am not sure whether the increased runout is showing on the target. The gun shoots under 1/2 moa and I have not took time and worked up a load.

 

[Preacher]

Very nice"
Were you able to duplicate this test?

Yes, 3 different times with the same 3 cases......

 

[Preacher]

Were these neckturned cases? Were they jumped or in the lands? Matt

Turned to .013-- .015 off......

 

[One Shot One Thrill]

I removed the expander ball from a Forster Die because I was fed up with stretching the brass neck back and forth followed by constant trimming, only to discover my Die would reduce the necks almost.010 - E Gads!
I could have sent the Die to Forster for honing but opted for a different path.

I have gone to using only FL bushing dies. With the correct bushing no expanding is required and you will be working the brass much less. This has proven to produce the least maintenance and longest life for me.

 

[stifffingers]

That was the path I chose as well.

I too use Redding bushing dies and competition seating dies. A tip to lower run out, this may surprise you but after you seat the bullet, lower the ram so you can get your finger on the loaded round and rotate it one third and raise the ram, then do it again. It doesn't take long and then check your run out. Make a comparison with several rounds. I do this for my match loadings.

 

[Bart B.]

I've heard a lot of good things about Redding products

For years, Sierra used Redding full length bushing dies resizing cases testing bullets for accuracy. Redding regular full length dies were used for others. RCBS Rock Crusher presses. Never prepped cases. Used the same load across all components lots.

 

[Dusty Stevens]

For years, Sierra used Redding full length bushing dies resizing cases testing bullets for accuracy. Redding regular full length dies were used for others. RCBS Rock Crusher presses. Never prepped cases. Used the same load across all components lots.

But what is acceptable to sierra?

 

[Bart B.]

But what is acceptable to sierra?

I don't know.

Interesting stuff from Redding:

https://www.redding-reloading.com/tech-line-a-tips-faqs/146-concentricity-problems

 

[Uncle Ed]

The best course of action is to not use any expander ball in a sizing die at all. Forster hasnt figured out any magic there- it still plows an expander back thru a case. They just put it in a different place to make you think it must work better (but it doesnt)

I do not live in fear of the dies expander and after testing seven different .223 dies the Forster full length dies produced the least neck runout.

And Redding put a expander in their bushing dies for a reason.

Tech Line & Tips (FAQs)
Bushing Selection
https://www.redding-reloading.com/tech-line-a-tips-faqs/140-bushing-selection
If the neck wall thickness varies more than 0.002", it may be necessary to use a bushing a couple of thousandths smaller than your calculations indicate, and then use a size button in the die to determine the final inside neck diameter.

Below I installed a Forster expander and spindle assembly on my Redding non-bushing full length die. And it greatly reduced the amount of neck runout vs the Redding expander. The reason for this is the Forster expander enters the case neck when the case neck is held and centered in the neck of the die. Meaning the Forster expander does not pull the case neck off center like other dies.

 

[Dusty Stevens]

I do not live in fear of the dies expander and after testing seven different .223 dies the Forster full length dies produced the least neck runout.

And Redding put a expander in their bushing dies for a reason.

Tech Line & Tips (FAQs)
Bushing Selection
https://www.redding-reloading.com/tech-line-a-tips-faqs/140-bushing-selection
If the neck wall thickness varies more than 0.002", it may be necessary to use a bushing a couple of thousandths smaller than your calculations indicate, and then use a size button in the die to determine the final inside neck diameter.

Below I installed a Forster expander and spindle assembly on my Redding non-bushing full length die. And it greatly reduced the amount of neck runout vs the Redding expander. The reason for this is the Forster expander enters the case neck when the case neck is held and centered in the neck of the die. Meaning the Forster expander does not pull the case neck off center like other dies.

What works for some may not work for others. I dont know of a single top level benchrest competitor that uses an expander ball, and dont know any that use forster dies. I do know a few shooters that have used redding dies for a little while but no expander ball was ever used. Itll be fine for hunting rounds.

 

[Nature Boy]

Admittedly unscientific sample size. 10 shots each, .308, 100 yards with a stock FN SPR

I continue to “feel” that run out is important, and the less there is the better. Of course, it could just be more reloading witchcraft.

 

[varget204]

Simple question I ask?
How much bullet run out does it take to make a difference? I am not interested in theory and the obvious answer only in answers that have been tested and proven.

I load and shoot thousands of rounds,i try to keep TIR under .0015 or less,.003-.005 are what a lot of factory rounds are.Almost all my loaded shells are .001 or less,when i get them that are .002 or more i shoot them as spoter or warm up rounds.If your trying to shoot Bug Holes at 100, or small groups at 1000 yards,would recommend you make them as concentric as possible.I have shot a Few groups in the High .1's and low .2's with rounds that were off .003-.004 a couple of times;but ALL the groups i have shot in the .1's and less,were with concentric rounds.Ask any Benchrest or Long Range Precision Shooter,they will all tell you,make them as cocentric as you can.

 

[Intheshop]

At the very high risk of sounding "Guffey", will just say, I believe a lot of guys are "leaving right much on the table" WRT assembling deadnuts straight ammo..... in the seating op.

And,hate to say this as well,but annealing plays a role in seating just like sizing. Both ops are relying on the brass "getting in line". The same way that sizing has to be controlled diameter wise( skipping the tension jokes?) ,your seating is as well. If there's any room/slop in how that case neck is being held..... along with the very short trip the bullet makes on "approach".... combined with anything other than a perfectly tuned bullet stem.... well,you feeling lucky today?

If you're happy with a cpl .001's of runout, carry on. Just sayin don't stop working on seating discipline.... the inline seaters are dang close but,even they can be better.

 

[Ccrider]

How much runout is induced by the chamber?

 

[dkhunt14]

How much runout is induced by the chamber?

I would say none. If anything and placed in or near the lands, it would straighten it. Matt

 

[dcali]

How much runout is induced by the chamber?

It should be unmeasurable. If it’s not, your chamber is jacked up.

 

[Ccrider]

How much runout is induced by the chamber?

I ask this because I have found that after firing, (and maybe before) some cases are straighter than others i.e. have less runout. I am not sure why. The runout for those cases stay lower.

Are you Gus saying that rhnout can be reduced by loading procedure.

Also, based on what I am seeing, .0005, .001 and .002 runout loads are landing in the same place on the target.