Bullet runout spec question

[7mm-08 Freak]

What is spec. Better yet what do you aim for. I have been using some EXPENSIVE dies and so far .002 -.003 is about the norm some of them are <.001 on the Hornady concentricity tool. I am checking just in front of the case mouth on the bullet. Should I go further towards the ogive? Cartridge in question is a .308,Lupua brass,Sierra 165 HP...Jim

 

[Ol' RD]

Re: Bullet runout spec question

Yes take it out just past the ogive.

 

[kraky]

Re: Bullet runout spec question

I have both the hornady correcting tool and the rcbs v block checker. I did not like the hornady tool at first. I believe if you follow their directions it gives you false info. I found the further you measure on the bullet towards the ogive on the hornady tool the less it will show you is wrong. This is because the bullet is held close to that point by the cylinder on the right side.
I feel the rcbs v block does a much better job of telling you how good your loaded ammo is. And what I found with the hornady is that to nearly match what the rcbs says is going on you should measure on the case neck (not the bullet) and do your correcting on the case neck. You will see alot more variation by measuring at the neck with the hornady tool and you will get much better correction by pushing at that point too. You want to do this just below the case mouth. I now find that if I get a correction down to under .002 at the case mouth my rcbs tool will also show very little runnout even when measuring out on the bullet with the rcbs. In most cases correcting there with the hornay will be just as easy as pushing on the bullet yet I think you will disturb neck tension less.

 

[ChrisGarrett]

Re: Bullet runout spec question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WM5L</div><div class="ubbcode-body">What is spec. Better yet what do you aim for. I have been using some EXPENSIVE dies and so far .002 -.003 is about the norm some of them are <.001 on the Hornady concentricity tool. I am checking just in front of the case mouth on the bullet. Should I go further towards the ogive? Cartridge in question is a .308,Lupua brass,Sierra 165 HP...Jim </div></div>

I use the Bersin concentricity gage on a 7 RemMag and my dial goes to 4/10,000ths, so I can get things measured and corrected to small numbers. I decided that I can get my target grade stuff down to a total indicated runnout of 1.2/1000ths, so .6 up and .6 down. For non target grade ammo, I can let it go to 1.6/1000ths, so 2 clicks up and 2 clicks down.

I'm just a hack, but this is what I decided was 'good enough' for me, even though I can diddle with things and eliminate R.O. entirely, if I spend the extra time.

I'll be getting the Bersin bodies for 223/308 and perhaps the 338LM body, in the near future.

Under 2/1000 T.I.R.O. is generally the point where it probably shouldn't matter much.

Chris

 

[Hummer]

Re: Bullet runout spec question

Wow, this is a deep deep subject. There was a long article on this back in 90s???? in Precision Shooting.
WM5L sent you a PM. 73s