unexpected poor loaded runout

[swadiver]

just got my first concentricity gauge. it's the Sinclair model. i am getting unexpected variable and very often poor runout on my loaded rounds.

here are the details:

Brass:
Lapua 6BR blue box brass.
three times fired in this rifle only
annealed
NOT neck turned

Bullets:
Berger 108's
seated .010" off the lands

Dies:
6PPC Lee Collet die for the necks with shim to modify them to work with 6BR brass
Forester Bench Rest Ultra Micrometer seating die

Press:
Forester Coax


Fired case neck runout::
less than .0005"

case neck runout AFTER Lee Collet die resizing:
.001" or less

Loaded round runout:

a very few at .001"
some at .0015" to .002"
a lot at .003" to .004"
and unfortunately: some at .005" to .006"

i am try to understand the cause for:

1) very poor .005" to .006" runout
2) wide range of variability in runout.


I do understand that NOT neck turning will increase variability in runout, but is this the only reason? would a hand seating die improve things? any insight appreciated

 

[Richard Coody]

well it is easy to get even lapua brass with a 1 to 2 thousandths variation in neck thickness. with a collet die that should be pushed to the outside and would only show up as runout on the brass neck not the bullet.

are you wet tumbling or leaving the carbon in the necks? i would say it is probably inconsistent neck tension and maybe inconsistent bullet seating procedure. wilson dies and an arbor press with a force indicator gauge will tell you quickly.

how do the high runout rounds compare with the low runout rounds on the target. could be an unnecessary concern.

 

[rardoin]

If you have not neck turned and are not mandrel sizing the I.D. of the neck you can have '0' runout on the O.D. of the neck yet the I.D. may have a bit. Try setting the stylus of the indicator on the I.D. of the neck, if you can, and check a dozen sized cases and see what your runout is. Also, if your seating die is not a great match for your brass this can compound the runout. The main culprit, however, is likely using unturned brass and the lack of neck wall uniformity.

 

[Steffen Bunde]

I take a bore brush and clean the seating die out every 100 rounds; a 45 cal brush for a 308 seating die for me. This has significantly reduced my bullet tip runout.

 

[Barlow]

I'm not clear on if you measured run out on the bullet or just neck. Barlow

 

[jepp2]

just got my first concentricity gauge. it's the Sinclair model. i am getting unexpected variable and very often poor runout on my loaded rounds

I'm not sure I wouldn't sleep better if I hadn't purchased my first concentricity gauge. I have 3 now. Kind of joking...

I used my gauge to mostly check case neck runout after sizing. I just kind of ass-u-med my Redding Comp bullet seating dies would take care of the rest. I couldn't have been more wrong. My numbers were similar to yours. I read somewhere that seating your bullet in 3 steps, rotating the case ~ 120 degrees each step, might/could improve bullet concentricity. Heck, that doesn't cost anything to try. Tried it and now my bullet TIR is about 1/3 what it was without rotating and seating in steps. So you might give it a try.

And yes, I went through that normal checks of making sure the bullet tip wasn't touching the end of the seating plug.

Realize where you measure the runout on the bullet will affect the reading you get. I strive to measure slightly forward of the ogive.

 

[Patch700]

A question for the OP... Since you are neck sizing , have you taken the seating die apart and just tried dropping a sized case into the sliding chamber? Do they all seem to sit and fit ok?

I have seen where a specific cartridge fired and sized in a particular manner would not properly fit in the sliding chamber.. The remedy was to ream the sliding chamber with the reamer used for that rifle... If that’s not available you may have to get inventive and salvage one fired case with some lapping compound along with a small drill and appropriate case holder and work it into the sliding chamber to get a closer fit.

If the cases are not being fully supported in the same manner every time then you can see where a problem may show up.

Lastly I would take a close look at how the actual seating stem fits with the sliding chamber... They do wear out and when the do they will obviously allow things to get out of alignment.

Good luck , let us know your findings

 

[dmoran]

@swadiver
Start by rolling a spent case on the neck and also in the neck.
Next after each step of your reloading procedures, roll it again (on & in).
When you pin point which procedure step(s) is creating run-out, address it and remedy the issue.

I use concentricity gauge's to tell me how well I am able to make my ammo, and how to maintenance my reloading equipment to keep runout minimal.

Like your choice in the Sinclair !.!.!
Donovan

 

[swadiver]

I'm not clear on if you measured run out on the bullet or just neck. Barlow

i check runout on the sized necks and then on the loaded bullet just down from the ogive

 

[swadiver]

I take a bore brush and clean the seating die out every 100 rounds; a 45 cal brush for a 308 seating die for me. This has significantly reduced my bullet tip runout.

i have cleaned it. i will check it again

 

[swadiver]

If you have not neck turned and are not mandrel sizing the I.D. of the neck you can have '0' runout on the O.D. of the neck yet the I.D. may have a bit. Try setting the stylus of the indicator on the I.D. of the neck, if you can, and check a dozen sized cases and see what your runout is. Also, if your seating die is not a great match for your brass this can compound the runout. The main culprit, however, is likely using unturned brass and the lack of neck wall uniformity.

thanks. not sure how you can put the stylus on the inside of the neck to check

 

[swadiver]

A question for the OP... Since you are neck sizing , have you taken the seating die apart and just tried dropping a sized case into the sliding chamber? Do they all seem to sit and fit ok?

I have seen where a specific cartridge fired and sized in a particular manner would not properly fit in the sliding chamber.. The remedy was to ream the sliding chamber with the reamer used for that rifle... If that’s not available you may have to get inventive and salvage one fired case with some lapping compound along with a small drill and appropriate case holder and work it into the sliding chamber to get a closer fit.

If the cases are not being fully supported in the same manner every time then you can see where a problem may show up.

Lastly I would take a close look at how the actual seating stem fits with the sliding chamber... They do wear out and when the do they will obviously allow things to get out of alignment.

Good luck , let us know your findings

thanks will check into this as well

 

[swadiver]

@swadiver
Start by rolling a spent case on the neck and also in the neck.
Next after each step of your reloading procedures, roll it again (on & in).
When you pin point which procedure step(s) is creating run-out, address it and remedy the issue.

I use concentricity gauge's to tell me how well I am able to make my ammo, and how to maintenance my reloading equipment to keep runout minimal.

Like your choice in the Sinclair !.!.!
Donovan

hi thanks. not sure what you mean by rolling the case and neck

 

[swadiver]

I'm not sure I wouldn't sleep better if I hadn't purchased my first concentricity gauge. I have 3 now. Kind of joking...

I used my gauge to mostly check case neck runout after sizing. I just kind of ass-u-med my Redding Comp bullet seating dies would take care of the rest. I couldn't have been more wrong. My numbers were similar to yours. I read somewhere that seating your bullet in 3 steps, rotating the case ~ 120 degrees each step, might/could improve bullet concentricity. Heck, that doesn't cost anything to try. Tried it and now my bullet TIR is about 1/3 what it was without rotating and seating in steps. So you might give it a try.

And yes, I went through that normal checks of making sure the bullet tip wasn't touching the end of the seating plug.

Realize where you measure the runout on the bullet will affect the reading you get. I strive to measure slightly forward of the ogive.

i will try rotating the case during seating. i did try turning it 90 deg in a two step process but that did not change anything.

i can check that the 108's tips are not contacting the end of the seating plug. seems unlikely given the 108's design, though

 

[dmoran]

hi thanks. not sure what you mean by rolling the case and neck

"rolling" = my nickname for; measuring them on your concentricity gauge. Both on the OD & ID of the neck.

Sorry for the confusion
Donovan

 

[Crosshair1]

Seeing as your using a shim, does the primer decap pin actually get to enter the flash hole when sizing occurs?

I use a 308 collet die and observed a slight improvement in runout moving from a standard lee seater to a redding competition.

I wouldnt get too hung up on it until you've shot your best runouts vs the worst and see if it shows on paper

 

[swadiver]

Seeing as your using a shim, does the primer decap pin actually get to enter the flash hole when sizing occurs?

I use a 308 collet die and observed a slight improvement in runout moving from a standard lee seater to a redding competition.

I wouldnt get too hung up on it until you've shot your best runouts vs the worst and see if it shows on paper

i have cut off the decapping pin on the Lee Collet die. also, the runout of the sized necks is .001" or less. as stated, i use a Forester seating die. the rounds are shooting well, but always looking to improve if possible. thanks for the input

 

[dstoenner]

i check runout on the sized necks and then on the loaded bullet just down from the ogive

You want to have the point of the dual indicator running on the full shank of the bullet as close to the olive as possible. If you get the point on the nose section then minor changes of position on the v blocks will show a false value of run out.

The procedure I use to seat the bullets is to seat the bullet about 50% then bring the press handle back up rotate the case about 90 degrees. Then fully seat the bullet. Then I raise the handle, rotate the case another 90 degrees and then bounce the handle of the press twice. And no this is not some magic potion.

I did tests on my loading procedure on a 3 sets of cases. Set 1 I seated bullets in one step. No rotation. I got about 35% of the 2 mil or less runout. Doing 1 rotation raised that 35 to about 50%. I was really sceptical of the double bounce trick but I tried it and sure enough I got another 10% or so in the 2 category.

I am also sceptical about not turning necks. No I would love to do something else but very few case necks, even Lapua, are uniform the full length and side to side. As you turn the necks you see all the inconsistencies before your eyes.

Also you will never get any batch of cases to all be 100 less than 2 mil run out. I load in batches of ~100 or 50. I sort in categories of run out. You always need foulers or back ups etc. Using that as part of your strategy will get better on target performance

David

 

[snakepit]

i check runout on the sized necks and then on the loaded bullet just down from the ogive

Were the results the same or different?

 

[Liven The Dream]

I have just to much time on my hands.
I shoot .308 Palma most of the time.
I check Run out on sized Brass 1st , then loaded on the bullet.
I have 4 different .308 Dies . This is where the Trouble starts !!!!
Best of the Best .. RCBS SB FL Die with Hornady floater ball . Win. or Lapua .005 to .001 .
RCBS . 308 Match Die .002 .
Now trying to control neck tension !
Reeding Fl Bushing Die ???
How you adjust the Bushing Free Play can change Run out from.001 to .011 .
For Me using Winchester Brass my 20 Plus year old RCBS SB Die is the Winner .
I have a Foster Die not a go to item in the room.
Best of Luck