Too Much Runout...

[Ron Ankeny]

Man I get a lot of runout on some of my rifle reloads. I can take a fired case that is perfectly concentric, run it through a neck sizing die and get .003-.005 run out. Then I seat the bullet and get .007-.009 runout. I produce some really crappy ammo. The press in a 15 year old Rockchucker, dies are all Redding Competition dies as is the seater.

I know I am being really vague, but what should I look for to remedy the problem? Is it possible the press is screwed up from my young and dumb days of forming brass with a 4 foot cheater bar on the press handle?

[tightloop]

Yep, Ron, that would be my guess...a new press might cure your anxiety...

[dillon]

Try tightening your die lock rings with cases up in the die and the handle pulled down. This helps ensure the die is centered in the frame. If you have the die lock rings fixed in place by a set screw, then back the set screw off. This will always tip the die to one side.

[Flexmoney]

I have nothing to add here, other than...

The technique that Dillon mentions sounds like the "squaring of the dies" that I read about in my Sierra manual.

[Ron Ankeny]

Ill try loosening the lock ring and squaring the dies again. How does one insure the expanded ball isn't the culprit?

[TBF]

Ron,

Don't fall for the " remove the expander ball and check the case trick ".

It doesn't work.

Sometimes the concentricity issue can be traced to the brass itself, case necks with one side thicker than the other sized with an expander , always come out with excess runout when measured on the neck. They come out looking far better if you remove the expander... Which is an illusion .....

If your Redding dies use bushings for neck sizing , be sure you are using the correct one. For some reason the " S " dies I have won't squeeze the neck any more than about .004 before they start to cause alot of runout.

Sometimes I think neck sizing with these dies and a standard chamber may not be a good combination.

Travis F.

[John Dunn]

My brother and I had Anatomy and Physiology class together at U of Michigan many moons ago. We were quizzing each other in preparation for an upcoming mid-term exam. Went something like this:

Me: What's the Gibb's Free Energy for thus and such reaction?

Bro: Don't care.

Me: What do you mean!?! The prof told us we had to memorize this crap. It's gonna be on the test!

Bro: Well, that's one I'll just have to miss.

And, from the way he said it (kind of cool and unsmiling), I could tell he really didn't give the merest crap (hard as that is to believe!).

Here's how this story relates to shooting: If my case run-out causes me to miss a target, or a burr on a flash hole increases my SD by 5, or an unturned case neck leads to the rise of the machines....I don't care.

That's one I'll just have to miss.

[Paradox]

+1 to dillon and TBF

In addition, I use a stiff brush to clean the top of the shell holder.

In my experience the following methods do not work for me:

1.) FL Sizing with an expander ball. I typically get .003-.007 runout.

2.) Bushing neck reduction in 2 steps (twice the work, same results)

Ironically, I have had decent luck using a Lee Collet Die and a Redding Type S FL die. I get .001-.002 runout and it ends up working the case necks less. A Lee Collet Die squeezes the neck against a .3055" mandrel (if memory serves). I also only set back the shoulder .001-.002".

If you are using the bushing dies from Redding, size the neck .002" under bullet diameter. For example, in .308Win say you have cases with a .015" neck thickness, you would use the .336" bushing. (Bullet diameter + 2x neck thickness - .002")

I have had the best luck with a custom FL sizing die that has had the neck honed to the proper inner diameter. This way, you know that the case body and neck are in alignment (at least when sized). Again, I only bump the shoulder .001-.002

As mentioned previously, some brass will just not stay true after it "springs back" in the resize operation. Match brass will often help in this area. Shhh don't tell anyone - but after uniforming the cases Winchester is making, I can't tell a difference (Unless you are looking for benchrest level accuracy)

I have a few theories about this, BUT I have found that runout affects group size more at short range than long range (Say 100m vs. 600m)

Have you ever wondered why Federal GM Match seems to shoot well in just about any rifle? Have you ever measured runout on the Black Hills or Federal GM? (I have 2 boxes of BH 168gr in front of me and just measured .004-.007 runout... ICK) I have also found that finding an Optimum Charge Weight / COAL, and good brass prep yield really tiny groups... (The OCW is a little off topic but if you want I will start a new thread about it.)

Well sorry for making this so long winded... Hopefully this helps.

[Ron Ankeny]

John:

Up until now, I didn't care either. I have been trying to figure out why I get so many fliers so I started checking and that's when I detected the horrible runout. Some of my rounds have horrific run out. I put the rounds with bad runout in one batch and the rounds with .003 or less in another batch then went to the range. At long yardage the difference is substantial. If I miss a plate I don't care. If I miss a prairie dog I don't care. If I cripple a big game animal, I care a lot. For now, I'll mark the rounds with little to no runout for hunting loads and shoot the others at the range.

[Paradox]

Ron,

Just curious, but what caliber / bullets / primer/ powder are you using?