Runout: acceptable ranges

[Stud Duck]

First, let me start by stating that I am strictly a hunter that doesn't shoot over 500 yards, however I do a appreciate little clover-leaf groups while zeroing and shooting on the range.

I just started reloading and have read so much information that I can't keep it all straight. That being said, I read somewhere about the acceptable limits of runout on case necks and on bullets once they have been seated, but can't recall where and haven't searched this forum, but will.

For instance, I just FL sized 160, once-fired, 270Win cases that were given to me and with my concentricity gauge, I'm showing .002" at the case neck.

What are the acceptable standards for runout on the following categories:
Competition
Hunting/Target shooting
Plinking
Garbage can

Thank you.

 

[chkunz]

Do not be concerned with anything other than competition. Then it depends on what type of competition. XTC with a service rifle, do not be concerned, XTC at 600yards with a match rifle, maybe, Long Range prone, maybe. I will let the F Class and Bench rest folks address their disciplines.

You will get a lot of opinions on this but not much information based on data.

 

[dstoenner]

I am not a hunter but what I have seen in shooting is that 3 mil runout on a loaded round cannot be seen at 300 yards on paper, 2 mil runout up to 600 yards and 1 mil runout up to a 1000. 1000 is all I have access to but I have very few cases when loaded have runout that is .5 mil in a loaded batch of 100.

If your neck runout is .002 then you should be in good shape. I would load up a batch and sort them by runout in order to cull any high runout rounds and take the .003 or less and go hunting.

David

 

[Prose]

.003 or better you probably are going to shoot as good as most people can shoot (or better than the rest of your components). The very best among us aim for .002 or better. I find that maintaining 1/2 MOA groups gets more difficult around .010 all other things being excellent. Curved barrels, off-center chambers, stress induced actions or barrels will completely negate perfectly straight ammo.

Chambers, dies, improper annealing uneven lube... all these can induce runout. Finding ways to reduce it requires a lot of advanced knowledge and equipment. If you have an actual problem creating .015 or worse runout it's worth tracking down, but if you aren't built from the ground up to have a near-perfect system there is only so much that can be done.

Recently switched to a MEC press and have been very impressed with the results.

 

[Stud Duck]

Great info so far, thank you.

I have a Forster Co-Ax press and used a Forster FL sizing die. I would assume that's not too bad for using an expander ball. It will be interesting to see how my Lee Collet Die compares.

I'll check runout again after I seat some bullets.

 

[Bart B.]

1% of bullet diameter near its tip is good enough to get sub MOA at 1000 yards if all else is up to the task. 1/2% of neck diameter near its mouth which is about the same angle.

No commercial loaded bullet runout measuring thing positions a bottleneck cartridge headspacing on its shoulder like they are in the chamber when fired. Depending on their setup, up to a few thousandths inch spread across them for the same cartridge is normal.

A perfectly straight such cartridge will have its bullet tip up to about .001" off center in the bore when fired. It's tip will be off center opposite that of the case off center at the back of the chamber.

Start with a resized case with its neck well centered on its shoulder. This is often best done with a one piece full length sizing die whose neck is about .0015" to .0020" smaller than a loaded round' s neck. Get rid of the expander ball. Resized case mouth should be about .0005" to .0010" smaller than bullet diameter.

If one starts with all the right stuff, it takes little time to make straight cartridges.

 

[hikfromstik]

How do you get to .001" run out ? Practice, practice , practice and money ,lol . I'm a novice (2yrs) Reloader and I'm just know getting my single digit SD's on one load consistently. I think it takes time . I thought I could jump in and shoot bugholes on day one ,but it doesn't work that way . You have 1 thing right , you're on the best precision/reloading forum online . These guys know there stuff . I'm 3 steps ahead of my other friends that reload because of this great place . You also have a great press ,so your already 1 step ahead . Good luck