Run out

LexRick

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I've been a member for a year now. Ive read plenty of coments about run out when resizing im not completely sure what it is. Could someone explain
 

YZ-80

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It’s basically a situation where the seated bullet is not perfectly concentric in the case. Most folks like to control (or correct) this to less than .002”.
 

nksmfamjp

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With the case set in v blocks (Axial stop at the base) at the shoulder and base, it is the wobble of the tip (usually measured just above or below where the seating stem touches the bullet.
 

nksmfamjp

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It’s basically a situation where the seated bullet is not perfectly concentric in the case. Most folks like to control (or correct) this to less than .002”.
I agree....what are your results when correcting? My 1/2 MOA rifle shot 1.5 MOA groups when I corrected.
 

LexRick

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Reason im asking is i have a 7mil stw and am having troble finding a consistent group. I thought it was the lee dies im using becsuse ive noticed a difference in oal after resizing.
 

Bravo 4

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Where are you measuring a load round for OAL? What bullet is being used? If it’s an open tip/hollow point bullet like a matchking, the tips (meplat) are not going to be consistent. If measuring base to tip of the loaded round it will throw you off.
 

Savage 12BVSS

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I only noticed problems with accuracy when correcting rounds that were .003 and above, you risk bending or pushing the case neck out of round with the force of tweaking them straight. If you use good die's (forster benchrest-whidden-redding) and remove the sizer button and stem from the sizing dies, you will greatly reduce runout in loaded cartridges. If you neck size with mandrel expander dies (sinclair style) or collet mandrel dies (lee style) it will further reduce runout in cartridges. Some presses with movement in the dies or shellholder to align dies and cartridge better (mec marksman-forster co ax-rcbs summit) will also help get you there with runout. Turning the cartridge at least once or even twice in the bullet seating stroke can also help in the runout elimination attempt. I produce loaded ammo that runs between .0005 to .0015 for four different cartridges, anything over .001 gets a light tweak on a hornady gauge pictured above to keep all rounds under .001 runout.

Some believe its unnecessary to adjust or care about runout, others do and can see the difference in a tight shooting rifle with a good marksman. I believe when you get to 1/2" or better its a worthwhile addition to your reloading methods. Its a no brainer that it's not going to make accuracy any worse to keep ammo straight as possible and its the tweaking hard on very high runout loads that can cause even greater problems than ignoring it all together. All IMHO and and with hands on experience, its not going to make a MOA gun suddenly shoot 1/4" groups of course.
 

YZ-80

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I agree....what are your results when correcting? My 1/2 MOA rifle shot 1.5 MOA groups when I corrected.
My results are everything maintains sub MOA. I’ve never seen groups open up as a result of using the gauge. Truth be told however, I don’t have any empirical data to back it up but I figure whatever I can do to keep things concentric is contributing to accuracy. It feels good, so I do it.

Now, with regard to dies - with RCBS I average .003-.004 runout and I correct them. With my Redding dies, I don’t even bother to check anymore.
 

misterc01

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Feb 15, 2019
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Florida Panhandle
My my last check after reloading my precsion rounds is the conentricity gauge. If I have done everything correctlty, by that time I need very little correction (force) to get to my personal goal .002 or less.
 

Almondgrower

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I only use my Hornady tool to check for runout , if I find it , I narrow down to the cause and correct it in the loading process ! I don’t like to ( push ) the bullet/case straight because it messes with neck tension causing another potential issue and possibly sending me down a rabbit hole ! Lol
 

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