bullet runout

britz

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Mar 11, 2007
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I am trying to get the most out of my loads, just like the rest of you I'm sure. I made a homemade bullet runout "checker" or what ever you want to call it. It consists of two sets of cradles and a caliper set to measure the distance from the bullet to the base when the bullet is rotated. It is pretty crude, but I think it is doing the trick. I notices that some of my older hand loads had pretty bad runnout. Does anyone have some tips to decrease runnout. I use Redding dies now (plain jane's) but I always put pressure on them with the press ram before I tighten the collet. I use a Lee challenger press, it has some slop in the ram. Suggestions?
Thanks, Britz
 
You know there is a tool called a Bersin adjuster. It's about a little over 200 bucks . It has a micrometer on one side and a pusher screw on the other to correct run out . you buy it by the type of caliber you are shooting. you put your shell in rotate to see what the run out is and correct it with the adjuster screw.
 
Britz, I have a Bersin adjuster that I don't use because I changed calibers. What are you shooting? I would make you a deal if you could use the one I have. /ubbthreads/images/graemlins/smile.gif
 
I am shooting a 300 WSM primarily, but I will be shooting a 22-250 and 325 WSM. I would like to hear more about this product too. To be honest, I was hoping for some advise on whether or not the press has a lot to do w/ runnout or if anyone had any tricks they used to get rid of it. I have been told that when the ram is fully extended, any play will cause runnout, is this true?
Thanks for the replys.
 
I shoot a 7 mm stw and 300 wby , whats it fit.

Go to 6mmbr and vendor Directory under Kinnman Coustom
Products
there is a picture there.
 
I had a Bersin tool in 22ppc/6ppc for my tight neck BR guns. I sold it a year ago because it was time consuming to straighten bullets, and because I load to jamb (bullet touching lands). I figured bullets would straighten themselves when they were tight into lands. Achieving .000-.005" run out is near impossible and is not needed, especially in a hunting cartridge. Usually, run out is caused by necks not concentric. After 1-2 firings, this should straighten out. Try lightly turning necks before re-sizing. Next, I suggest Redding or the new Forster sizer bushing dies, and a good seater. Good shootin!
 
So what you are saying is start to seat bullet part way and turn shell 1/4 to 1/2 turn and finish seating to desired depth.
 
Most bullet runnout is caused by pulling the case over the expander ball in your die. When the expander isn't centered in the middle of the die it will pull it off center. Below is what I copy to forums when this topic comes up. I had a friend try this tuning a week ago and he wound up getting less runnout than with his fancy Redding Bushing dies! Here is the info:

My $.02 worth---ALL dies with expander balls need tuning. Think about it...a piece of typing paper is .003" thick--what are the odds that the expander is not PERFECTLY centered in a die and could pull a case slightly off center??? Pretty good I'd say. Pull the expander stem out of the die (and now is a good time to clean the inside of the die). Run about 5 brass into the die and see if they come out concentric. If they do (and usually they will) you now have to try and get that stem centered on re-assembly. A great way that helps is to put a piece of very concentric brass up into the die to hold the stem in place as you tighten it down. Sometimes this takes 2 people unless you have 3 or 4 hands. AFter reassembly try sizing some brass and check runnout. If not good then do very small turns of the expander stem--probably 1/32 of a turn at a time. Resize some brass and repeat the small turns. At some point I can almost guarantee that you will get GREAT RUNNOUT CONSISTANTLY. (Somehow, someway the expander spindle will hit almost perfect centering in the die body) I have many dies that consistantly make less than .002" runnout after sizing with most of the brass at .001" and less. I own, hornady, redding, forester, rcbs, and lee dies. ALL OF THEM HAVE BEEN TUNED and most make fantastic ammo and all make good ammo!! I have never ever got a set of dies from any factory that made as good of ammo as those that I have done this simple work with.
 
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Achieving .000-.005" run out is near impossible and is not needed, especially in a hunting cartridge.

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Gene,
Did you mean .000 - .0005"? As .005" is easy to achieve with good brass and procedures. I reloaded 35 rounds for my 7RM this weekend, only 3 rounds were more than .002", They were around .0035". Most of the others were around .001-.0015" runout with several being less than .001". Measurements were taken 1/4" back from the tip on the loaded round using a Sinclair Concentricity gauge.

BUT, this is with GOOD Brass (Norma in this case). With mixed brass that has large neck thickness variations, I've seen typical .007-,008" runouts. In my opinion, it comes down to #1 starting with good brass #2 good procedures to not mess it up.

Don
 
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My Bersin tool fits 308 and 6.5/284 & 284 Win. Anyone interested, post a reply or send me an email.

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Please send me some details.
 
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