I am brand new to reloading. I havent reloaded anything yet but have all of my equipment and components. I have read the ABC's of reloading 3 times and lymans 48th edition maneul 2 times. I still dont know or understand what this bullet run out is. Can someone please post a picture of it and explain it to me in idiot terms.

Don't have a picture but will give an explanation...in my own idiotic terms.

Run out is nothing more than a measure of concentric variation from the axis being evaluated. In the case of ammunition there are two points of interest for most of us. One is the case mouth, the second is the seated bullet. You may or may not be aware but several loading suppliers can provide tools for evaluating this. RCBS makes the Casemaster, as an example. The cartridge case is placed in a pair of Vee Blocks and rotated after a ball micrometer is put in contact with the surface to be measured. The reading will be in .001" increments but that is not the point so much as the fact that the case mouth or bullet is not concentric, and by what relative proportion. I say proportion because the amount of displacement indicated on the mic is proportional. Moving the contact closer to the actual case mouth, or bullet tip will result in bigger numbers. .000" variation is an objective, but not a necessity. Learning to achieve perfectly concentric ammo is an education in itself....and you can go slightly nuts, and a lot poorer as a result. Most guns are sensitive to cockeyed ammo, some are not. Your application says a lot about the need to deal with the matter, bench rest shooters worship the Gods of Concentricity, pistoleros can't even pronounce the word...some of them anyway.

I think I am now even more confused than ever. Will bullet run out cause a KABOOM. Or hurt me or my guns or anyone around me. Decrease gun life, barrel life, or case life?

Just read how to reload,then read how the dies get setup and load.Use a caliper to check C.O.L.=cartridge overall length.I load win 64gr pp bullets and 55gr sp bullets without any problems for my RRA AR-15 .223 I also don't crimp .223 for my semi-auto,its not needed!
Keep it simple when learning how to reload!

Run out is how crooked your bullet is seated. Less run out the better, means a straighter round. If it does not start straight it will not hit the same spot. Example a bent arrow. More it is bent the less control you have. Exactley what Dan described.

I have measured run out in factory ammo and ainmy handloads.
Factory ammo: .204 Ruger w/ .003-.012" runout / 3" group at 300 yards.
Hand loaded ammo: .22-250 with Redding dies on a Redding turet press. 0-.0005" run out / 1.5" group at 300 yards. Obviously this isn't an apples to apples comparison, but the point I'm tying to illustrate is that with .012" run out the ammo still shot fine.

Basically both loads are capable of centering a ground hog at 300 yards. My advice, don't worry about it, your handloads will have less runout than any factory load out there.

Unless you get into shooting benchrest or long range High Power matches, it will most likley never effect your shooting. This is one of those items that is a non-issue for most shooting.

No Kaboom, just the crooked thingy. Shoot more, load a lot....when you've been at it awhile you'll know whether you want to fool around with it. Run out equipment could also be marketed and an "Anal Retention Gauge".

I understand your confusion on the matter and there are a lot of opinions on the matter, some of the extremes represented already. I handloaded for 20+ years before I found out about the deleterious effects of excessive run out and never knew I had a problem. After discovering I was shooting crooked bullets...somehow my marriage survived...

quote:

Originally posted by DigitalDan:
No Kaboom, just the crooked thingy. Shoot more, load a lot....when you've been at it awhile you'll know whether you want to fool around with it. Run out equipment could also be marketed and an "Anal Retention Gauge".

I understand your confusion on the matter and there are a lot of opinions on the matter, some of the extremes represented already. I handloaded for 20+ years before I found out about the deleterious effects of excessive run out and never knew I had a problem. After discovering I was shooting crooked bullets...somehow my marriage survived...

one of the best posts about runout I've ever read.....thanks DD.

I get it now thanks guys. I'm just not going to overly concern myself with it at this point now that I know what I know.

Speaking of runout...

There's a way to keep runout down to .001" without any additional work. The trick is to fire prepped brass in a match chamber that does not allow your brass to expand by more than .003". This will keep runout down to about .001" without resorting to the bersin tool. If you're anal, the bersin tool will reduce that runout to .000"

Ditchdoc,

After reloading for several decades, I still hesitate to start measuring runout (I am close enough to criminally insane without going there). If you roll your loaded cartridge on a level surface and the bullet tip doesn't move noticeably (inscribe a circle in the air), you're probably doing better than a good few other reloaders.

quote:

Originally posted by ditchdoc:
... I still dont know or understand what this bullet run out is. Can someone please ... explain it to me in idiot terms.

Hey Ditchdoc, Apparently it is something that affects those Reloaders who use Neck Sizing Dies to Neck Size their cases.

Over the years I've found that Partial-Full Length Resizing(P-FLR) is more accurate than Neck Sizing, so I just stay with the P-FLRing.

Perhaps the accuracy difference is due to the Concentricity or Run Out and then again maybe not. I don't know if my cases have any Run Out because I've never bothered to take the time to measure for it.

I can't remember if you mentioned what type of "Action" you are talking about though. If it is a Bolt Action and most Single Shots, you can use either P-FLR or Neck Sizing and do OK.

If it is a Semi-Auto or a Dangerous Game rifle, then you need to be Full Length Resizing.

Best of luck to you.

It don't matter what you do. Sizing brass fired in factory chambers induces runout. Sizing brass fired in match chambers does not.