I decided to buy a concentricity guage to measure runout on my reloads(big mistake) I've been measuring for hours and getting frustrated. What is considered exceptable runout?? The outside of my case necks run from .002-.003. The loaded rounds (measuring the bullet) runs from .002-.005) These are hunting loads but I want the best accuracy I can get.

hglas, you're not the first person to be driven up a wall by concentricity.....and likely not the last. A poster named "bigcountry" was driven insane by this same issue.......maybe he'll see this and post his results.....but here's something that I was told years ago and it's not too bad.....it's really Rube Goldberg but it's not all that bad afterall.....

clean your loaded shells and roll them on the kitchen countertop.....something really flat.....roll them rather fast and visually look for wobbling bullets. The ones you can visually see runout should be picked out and shot for practice.

The difference between benchrest rifles and hunting rifles is a little akin to the difference between a car in the Indy 500 and my F-150......some of us really want to be in the Indy car.....but own an F-150

There's not a right number for runout.....the proof of the reloads is at the range.....not at the concentricity gage.

There's a long list of reloading tools that only benefit those that are already shooting well under MOA....and that's one of them.

first of all. in order to load streight ammo you have to start out streight. premium brass, lapua, will give better results than say win or rem. new brass compared to once fired usually produce streighter rounds.
resizing the brass will produce the biggest runout.
If you use bushing or collet dies you will have better results.
I neck turn once fired new brass, win or rem. just enough to clean it up. it runs from.0005 to .003 due to the neck wall thickness of the brass.
I have found that if i use the collet dies for neck sizing
The run out improves to with in .0005 to .0015.
Never more than .003, if it does i recheck my die aleignment set up.also one other thing that i have found that affects run out is that the bullet seater does not match the ogive of bullet causing it to tilt/.
i try to stay inside .0015" you can really tell the diffrence at ranges past 300 yrds.

I'm reminded of a friend that was obsessed with mileage in his car.....he opened a auto mail order catalog...Whitney IIRC.. and ordered things that promised better milleage.

There was a gizmo that promised 5% better mileage....and a widget that promised 3% better mileage and then he found a thingamajig that promised a whopping 10% better mileage.....etc.

He ordered all the things he could find and installed them only to find that he couldn't drive the car more than a couple miles before he had to stop and drain a little gas out of the tank.

If you are shooting matches,..then it matters,..but if you are shooting game it don't make a tinker's damn. I use match rifles for hunting,..so I have no choice but to load straight. COMPETITION dies with the sliding sleeve that grabs the case make a big difference as do the in-line dies.

Just my thoughts on concentricity...

And I have though about this entirely too much.

Less is better than more. ( DUH ! )
Too much is when it matters, a 15 LB rifle on a concrete bench with a 36X scope and a trigger pull measured in ounces will show things that will never be obvious to most of us normal guys.

As mentioned above the measurement is directly affected by the amount of variance in neck wall thickness. The use of an expander is very advisable ( IMHO ) when not turning case necks. What you see on the outside matters less than what the bullet sees on the inside. The expander will move the variance to the outside of the neck where you can measure it with a concentricity guage. Not using an expander will leave the variance inside the neck where it will be partially moved around by the insertion of the bullet.

I do not notice any significant difference between .0000 and .004 in most rifles.
Further more I tested some very accurate loads I worked up in my 300WSM that I segregated by concentricity, and found that when the bullet is seated into the lands concentricity seems to be less of an issue than when there is alot of bullet jump. The loads showing .006 - .008 shot as well as the loads showing less than .002 .

This is all speculation by a guy who does not own a scope over 20X.


Travis F.

Pretty much everything that you need to know has been written here. However, I just can't resist adding a couple of things.



1-Been there, done that. Got frustrated, too.



2-This topic has been researched by some pretty sophisticated folks. Some for the NRA technical staff and some for Precision Shooting magazine. Some people find that the effect of runout is significant (NRA & PS), and others don't (PS). I don't know why, but considering some of the investigators, it may be due to a lack of investigative rigor. Then again, maybe it isn't.



I have a .220 Swift for which I only load 'em and shoot 'em and it shoots great, really great. No baloney. No spinning, no nothing, so I gave up trying to figure it out. Perhaps when you get down below a half-inch group, it matters, or something like that.



Spend most of your time on the range and practice your shooting and less time in the loading room.

FWIW--some of the best shooting loads I had were made before I got my gauge. I was shocked to find out they had .007" runnout when I got the gauge. ANYHOW--I do try to tune my dies for less runnout. You'd be dumb not to. Also I think runnout probably has less effect on short stubby bullets than possibly big long match grade bullets.
(Cant say why--I just visualize it might be easier to realign a short bullet as it goes down the barrel than a real long one). If I'm hunting here in Wisconsin where shots are rareley over 100 yds I could care less about runnout. But just in case it does matter (and I'm not totally convinced in a hunting rifle that it does), and I'm going on a long range hunt out west or up north, I do sort my ammo by runnout. Those under .002" are marked with a green marker on the primer. Those .002-.004 are not marked, and those over .004" are marked with a black marker.
The black ones are last minute, double check the scope rounds. The green ones are loaded in the rifle for hunting, and the neutral ones are to fall back on in case I run out of green ones. BY the way----the black ones shoot just great if the gun likes the load!! I guess the green ones give you a little "upper of confidence" when you load them and help fire me up for the hunt!!

What I found thru enormous effort was it depends on the rounds. A freebored caliber like my 300RUM or even STW, seems very sensitive to alot of runout. What you see with these calibers or like ones is flyers. You get unexplained shots 1" away from a 3shot group touching.



I separate my ammo in three groups. Bullet runout greater than .004", bullet runout between .002 and .004" and runout less than .002. So out of 30 rounds, I would have 9 or less with bullet runout less than .002. 12 or so would be the midrange. And some would be bad like .006". What I have noticed is I can't really tell the difference in ammo with runout less than .002" and the ones between .002 and .004". But, but, I do get flyers with high bullet runout with loads that are very accurate with low runout. Many other factors play in this. Neck thickness, bullet quality.



So to get better ammo yeild I turned to neck turning. Just slight neck turning. The main culprit is my Remington brass. Bascially I am polishing a turd. But its the only turd in town. Now out of 30 rounds loaded, 24 or so have runout less than .003". The other 6 usually are on the other extreme like .006". I use these rounds for fouling.



Ok saying all that, reloading was much more fun without concentricity. Now its turned to a tedious time consuming thing. And once you go this route, its hard to turn back.



Rounds like my 308, 270, etc don't seem to be affected by large bullet runout like my 300RUM. But then again quality brass is available for all. I tried several times comparing 308win groups with rounds with runout .006" and rounds with .002". I just couldn't see a major difference. But saw a notable difference in my 300RUM shooting with max loads and remington brass.



One way to save yourself some agony is to invest in good brass. Lapua is one if available. Federal is another but you have to get once fired or you fired.



Also, what vapordog was saying about rolling them actually works. If you can see any wobble, then runout is probably over .004". I was surprised myself.

IMHO the easiest (if a little expensive) way to deal with Concentricity is to load them as straight as you can and then use a Bersin tool for your concentricity guage - it will straighten them also. You can get most ammo under .002, and if you load carefully you can straighten most of it to .0012 or better. Most of the best groups I've shot lately have been with ammo straightened on by Bersin tool, it does make a difference even at 200 yds........DJ

Vapo, Here is a link with a good description of the tool.......

http://www.centuryarms.com/bersin.pdf

I bought mine from here.....

http://www.kinneman.com/

I bought a set that has 1 dial indicator and 3 bodies. It allows me to do 223-308's, 30-06-300 Win Mag, and lastly 300WSM-300Ultra's. This setup cost me about $475 a while back.........DJ



-OK secrets out I expect to see some great groups posted?