OK, so I probably did myself a disservice and bought a Redding slant bed concentricity gauge to measure my 6.5 Creed loads.

Using Hornady Custom Grade dies on a RockChucker with Hornady shellholder I measured about 0.001 runout on the outside neck surface of a freshly sized brass.  Brass is all Hornady and I keep it in groups according to # times fired.

Seating a Hornady 140 ELD-M and measuring runout gives me the same 0.001 on neck, 0.004 just in front of the neck on the bullet, and 0.008 at the ogive.  More toward the tip and I'm getting 0.010 TIR.  Very occasionally I will get a result that's 0.001-0.002 on the bullet just in front of the neck and 0.004 at the ogive.  Probably 10%.

So, thinking I can improve this I bought the Forster full length bushing size + micrometer ultra die set.  Measured loaded round neck diameter at 0.290 so I inserted the 0.288 bushing and backed off the bushing nut 1/8 turn from full down and adjusted the expander to start expanding while the neck is still exiting the bushing.  About 1/3 of the bushing (but not the widest point!) is inside the bushing.

Sized some once fired cases and still measuring 0.001 TIR on the neck.  That's not the part I'm bummed out over.  I think that number is just fine.

When I adjusted and used the new super duper seater, I get the EXACT same TIR measurements as the Hornady dies.  Arrrrgh.  This was an expensive test.

So, my question is - from those who load benchrest, precision rifle, etc. - is my Rockchucker holding me back?  Would I honestly see improvement going to a Co-Ax style press?  I watched the Ultimate Reloader single stage shootout and his results show the RCBS Summit with best TIR numbers.

My Rockchucker (I bought it in the very early 90's) has quite a bit of play on the ram when it's all the way up.  360 degrees of flexing motion on the ram but the shellholder will restrict brass slide motion that to 90 degrees of float.

You want to use a good inline bullet seater. Wilson comes to mind. Seated using an arbor press, not a Rockchucker. If you use the Rockchucker, float the shell holder by removing the spring clip that holds the shell holder.

Thanks! Looking at arbor presses and the LEW die.

Op, for the most part it is not the press, if you take freshly shot brass and run it over your concentricity gauge you will find if your chamber was well done, that the necks are perfectly concentric...What takes them out of concentricity the most is the expander ball, pulling it thru the neck pulls the neck out of concentricity...Removing the expander and going to a mandrel die that sizes on the in stroke will solve much of the concentricity issues, or at least it has for me...So you neck the neck down with a bushing die(without the expander) in one operation, then come back and expand to finished diameter with a mandrel die, which should solve your concentricity issues unless you have other things causing issues...Easy to trace with the gauge and checking after every operation to find and fix the issues...

OP,

What kind of groups are you typically getting?

Are you measuring concentricity because you want to, or because you feel you need to for improving performance?

Things to consider
# 1 When seating your bullet start in half way and the drop the ram and spin the case 180 degrees
# 2 Quit using the expander ball let the bushing control the neck tension, and if you have an out of round case mouth...think mandrel die.  
# 3 An arbor press and inline seater sounds like another step

The very first groups with Hornady factory 143 ELD-X ammo were 0.390 MOA at 100.

My loads with 140 ELD-M in Hornady brass, Fed GM215M, and hand trickled on analog balance beam Superformance or H4350 are all under 0.400 MOA at 100.  But this is all at 100 where the small things won't rear their heads.

I want to try the rifle at longer ranges when they come available so I'm looking to take any possible negative variable out of the ammo equation.  I have the SD and ES figures from chrono at home.  My 300WM loads easily beat the 6.5 loads in ES.  10 rounds with IMR 4350 and Hornady 168 AMAX (bought lots of these many many years ago) seated 0.040 from the lands usually give me 10fps ES and those are just loaded on a regular $60 set of Hornady dies.  Obviously as I progress to longer ranges, the ES will play a bigger part in my vertical dispersion so I have to minimize it.

Part of this is to duplicate the results others get.  When they are getting 0.001-0.002 in front of the mouth and 0.004 or so near the bullet tip and I'm getting 0.004 at the mouth and 0.008 to 0.010 out there it makes me want to produce better ammo.  I get that a lot of people say that runout means as much as a hill of beans but to me it's still a correctable flaw.



I'll try #1 tonight.  Easy to test.

#2 : I'll try that tonight as well.  I ordered 21st Century mandrel die and 0.2625 mandrel today.

#3 : Ordered arbor press and LE Wilson inline seater with VLD plug today.


I plan on changing one thing at a time to monitor changes.

Could be your chamber

Could be your brass

Could be your dies

Expander ball is usually the issue as the upstroke pulls the expander through the neck as case becomes unsupported by the die.   “In a sense” “ bending the neck” (layman’s explanation)

For precision loads:  Us a bushing die w/o expander or use a mandrel die to open up neck to desired neck tension

Also check the necks.  It is not uncommon for brass necks to be thicker on one side causing this.  Neck turn to a 80% clean up helps.

The only brass I’ve used that is consistent is Lapua and believe it or not I bought some Sig brass for my 30-06 when brass was hard to find and I was impressed with how consistent it was.

Edit:  I’ve found Hornady brass to be horrible….TMMV


All the posters above have provided good advice

I won't use hornaday brass it sucks, hard to keep the primer pockets tight and their consistency sucks..Actually got some norma brass a friend picked up for his 375 H&H, actually impressed with it, with in 2 grains and very very consistent across the 100 cases...and the price was very good...

Update:

Got my K+M arbor press, Wilson seater, and 21st Century Gen X Expander + 0.2625 mandrel.

Took the shellholder retainer spring out of the RC press as previously suggested.

First I took one of the brass I already sized and resized in the Forster die without the expander.  Measured 0.003 TIR midway down the neck.  Started looking for a window to jump out of.

Took my Hornady sizer, removed the expander assembly and sized same piece of brass.  Needle jiggle.  Almost NONE!  Holy crap, we're onto something here.

Ran the brass through the expander mandrel.  Still needle jiggle.  Basically zero runout.  Hell yeah!  So this combo can make some concentric brass plus I'm expanding 0.0005 over previous to reduce the ridiculous seating force.

Time to play with the new seater and press.

I measured my chamber again with the Hornady (former Stony Point) gauge.  Set the seater 0.035 off the lands which is close to where I was plus it moves my COAL to 2.800 which exactly fits my mags.

Took that cartridge and measured it.  Neck still zero.  Bullet just in front of the brass was zero.  OMG, feeling good about this.  The unbelievable thing (to me at least) is the ogive has zero TIR.

You all gave some dang good advice.  Expensive but good.

So on my next batch of loaded ammo I'm going to add cleaning the necks with a bronze brush in a drill and using the Imperial graphite in balls neck lube I bought at the same time and see how that affects my ES and SD numbers.  I may get another expander 0.0005 bigger (0.263) since it seems like I still have a lot of tension and chrono some more.

Outstanding!!!

Make sure you post your results at the range

Glad you got it straightened out OP...

<#1. This is a proven technique that reduces bullet runout, even when using economy dies.

#2.  Spin polish your expander ball, reducing it's diameter .001" or so. This will get you a little more neck tension, so you won't need to crimp.

Try placing a 7/8" diameter O-ring between your seating die lock ring and the top of your press. This will allow the die to float in the course threads, centering it better.

Glad you found a way to beat the RO nightmare.

I went through a similar quest and found the my Redding bushing dies and competition seater wouldn't give any better results than you were initially getting. I thought it was the seater and have been using "o" rings for decades...  For me the cure was to rotate the case 3 yes three times in the F/L body sizing die.  Full strokes each time.  My theory is the Hornady brass needs to be coaxed back to round.  For what it's worth I get 6 firings at 2825 ft/secs with my 140 grain load. Rifle is a true hole on hole performer. Wiseman custom barrel.

Wiseman Ballistics