Re: Bullet Runout Issues??
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mussman</div><div class="ubbcode-body">I am using 6x fired Hornady 6.5 CM brass
I just annealed the brass on the last go around.
I am using the RCBS Case Master Concentricity Gaging Tool.
I am running the pin directly over the top of the neck and about half way between the front and back edge of the neck.
Link to RCBS Gauge </div></div>
couple things,
If you're brass starts out varying in neck wall thickness, it will only worsen after each subsequent firing and resizing as the brass flows. Most companies even Lapua tend to have a thick and thin side of brass. The premium brass tends to vary much less on the order of .001-.0015" at the worst. I've seen certain lots of winchester brass vary .002-.003" in neck wall thickness.
Neck turning can help some but it won't fix a bad piece of brass.
run your concentricity gauge on the body of the fired case and not the neck. Is there any run out? There shouldn't be or very minimal. Then measure your concentricity on the neck of the fired brass.
Once you have those measurements Then run your case through the sizer die.
Check the runout on the body of the case and then the neck. I would suspect that the runout on the body is about the same. If the neck is out of wack then I would supsect your bushing is the causes. However, I have my suspicions that it's not the bushing directly. Someone already alluded that if you're sizing down too much in one step with a bushing die that will alter your concentricity and they are correct. Redding recommends not sizing more than more than .005" in one step.
Measure a fired case neck OD. Then take a sized case and measure the neck OD. If the difference is more than .005" then you might need to size down in two steps unfortunately.
Lastly, regarding most bushing dies, including the redding. By their inherent design, bushing dies will not size the full portion of the neck. It will size about 90% of it but won't get down to the shoulder neck junction. If indeed the necks of your fired brass coming out of the chamber spins .003" TIR then after sizing your bushing is adding another .003" from a large amount sizing (over .005") then yes it's very possible that you're having such high run out numbers on your sized brass.
Personally, once I figure out how much neck tension I need for a set up, I have forster hone out the neck on my full length sizer and do away with the bushing and expander ball all together. I've been really happy with my results that way.
Nothing wrong with the bushing dies, but I prefer to have the whole portion of the neck sized. Others do not, and believe leaving that last bit of neck unsized helps with concentricity and centering the round in the chamber. To each their own.
From what i understand this is all prior to measuring run out on your loaded ammo correct? Typically seater dies, even the best of them won't make brass any straighter than it started, so I wouldn't expect your run out on loaded rounds to be any better.
The real questions is, how far are you shooting and does it make a difference for your particular shooting. If you and your rifle can shoot the difference between the higher runout rounds and the lower runout rounds and it is significant for your shooting, then I would press forward and keep trouble shooting if you desire. IF it doesn't, I wouldn't sweat it, load and shoot.
