Author Topic: Reducing runout  (Read 678 times)

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Offline Buckskin

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Reducing runout
« on: July 05, 2011, 06:13:07 AM »
I just found a simple step from an article for reducing bullet runout that really amazed me. Now this trick is for guys like me who use standard dies, not those fancy competion dies.  I use Lee Collet dies in a few calibers, but obviously that's not possible for my AR.

Some of the issue with runout occurs when the expander ball leaves the neck, if the expander isn't true it will tweak the neck. I pulled the expander, sized the brass, then replaced expander and instead of pulling the neck open, I pushed it open.  Really made a big difference reducing my runout.

Now I should mention that along with the cheap dies that I use, I also use the cheapest runout gauge. A mirror...
But even so, my runout was noticable improved and my cull pile was reduced 80% with this little trick.

I am planning on getting a gauging tool and am considering the RCBS, any input on this or other gauges would be great.
Buckskin

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Offline quickdtoo

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Re: Reducing runout
« Reply #1 on: July 05, 2011, 06:49:30 AM »
Quote
I am planning on getting a gauging tool and am considering the RCBS, any input on this or other gauges would be great.


I use the Hornady tool to check runout of loaded ammo, also have the RCBS, prefer the Hornady, bought mine from Midsouth.

Tim

http://www.hornady.com/store/Ammunition-Concentricity-Tool/

http://www.midsouthshooterssupply.com/item.asp?sku=00005050076
"Always do right, this will gratify some and astonish the rest" -  Mark Twain

Offline wncchester

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Re: Reducing runout
« Reply #2 on: July 05, 2011, 07:30:10 AM »
Any runout that can be visually seen is gross.   

For measurement tools, some who post on the web like the RCBS Case Master but I often wonder if they have anything else to compair it too.  My runout gage is my own design and shop made.  It's a lot like the Sinclair, which is what I would have IF I had to buy one; cost is rational and even with their less expensive dial indicator the quality and function is great.

We can't load straight ammo in bad necks.  As you have learned, a conventional expander is a handicap but I think a good part of what causes most runout is too much "bullet tension",  that is the neck Inside Diameter is too small so seated bullets tend to start jammed at an angle that never gets completely corrected as it goes in.  Thus,  no amount of seating part way then turning to finish accomplishes much.   Those who proclaim we need 3-4 thou of 'tension' are wrong, about ONE thousanth of what is commonly called "tension" is all we need to hold bullets as tightly as possible and that allows better/straighter seating as well.

No expander or neck ID or comp seater will load straight ammo if the neck inside and outside runs at diferent angles so lighly turning most necks just enough to even things up a bit can be an aid.
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Offline LaOtto222

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Re: Reducing runout
« Reply #3 on: July 05, 2011, 08:12:17 AM »
No doubt that a neck has to be straight to minimize bullet run out. A crooked neck leads to a crooked bullet. Before I got the fancy dies, I used plain RCBS dies. I loosened up the expander ball shaft so that it "floated". This was so the neck did not get pulled one or another. It helped, I never tried to expand in a separate down stroke step, it might work.

I also have both RCBS and Hornady bullet run out gauges. The jury is still out as to which one I like best. One can show little run out and the other will be out - they do not correlate. I like the RCBS, but I have issues trying to keep the bullet into the bottom of the "V,s" consistently. The jury is still out on the Hornady yet, I just have not used it enough to say one way or the other. I made a home made bullet run out gauge. I made two "Vs" out of sheet metal bent over the ends and mounted them on a piece of wood. I then drilled two holes spaced a little further apart than the case, about mid way between the Vs. I ran a string up through one hole wrapped it around the case and back down the other hole. I could then spin the case and watch the bullet tip. I could vary the speed of the spin, by how fast I tugged the string on one side. I could not measure how much run out I had, but if it was very bad more than .003" or so, I could detect it wobbling if spun fast enough. I could then make adjustments to my loading techniques to remedy the situation.

I also agree the lots of neck tension leads to crooked bullets. I have had bullets that you could pull out with your fingers that shot lights out. Problem was they had to be handled with extreme care so they did not fall apart before you pulled the trigger. They have to just have enough tension to hold them into place reliably. Reliability depends on the application too. If I were on a life time hunt where reliability is a must, I would use a bullet crimp. For the bench or PD fields - no crimp and as light of tension as I can get by with reliably, .001" is enough.

Good Shooting and Good Luck
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Offline quickdtoo

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Re: Reducing runout
« Reply #4 on: July 05, 2011, 01:25:35 PM »
The nice thing about the Hornady tool is it will remove runout after the round is loaded if the cause is either a bullet seated  with yaw or bent necks, works on factory ammo too, I "fixed " several 260 Remington 140gr factory rounds that had .006-.007" runout, most had .001-.003".
 
Tim
"Always do right, this will gratify some and astonish the rest" -  Mark Twain