Checking for runout on finished rounds, the "low spot" on the case neck rarely lines up with the low spot on the bullet. Which do I use for indexing?
Index runout off case neck or bullet?
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Re: Index runout off case neck or bullet?
Bullet bearing surface just in front of the case neck, what tool are you using?
Bullet bearing surface just in front of the case neck, what tool are you using?
Re: Index runout off case neck or bullet?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sirk</div><div class="ubbcode-body">Checking for runout on finished rounds, the "low spot" on the case neck rarely lines up with the low spot on the bullet. Which do I use for indexing? </div></div>
Um, whut?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sirk</div><div class="ubbcode-body">Checking for runout on finished rounds, the "low spot" on the case neck rarely lines up with the low spot on the bullet. Which do I use for indexing? </div></div>
Um, whut?
Re: Index runout off case neck or bullet?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sirk</div><div class="ubbcode-body">Checking for runout on finished rounds, the "low spot" on the case neck rarely lines up with the low spot on the bullet. Which do I use for indexing? </div></div>
Do you mean when you load the chamber?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sirk</div><div class="ubbcode-body">Checking for runout on finished rounds, the "low spot" on the case neck rarely lines up with the low spot on the bullet. Which do I use for indexing? </div></div>
Do you mean when you load the chamber?
Re: Index runout off case neck or bullet?
402, using RCBS case master, and that is where I was measuring. So use the bullet to index, right?
thanks,
402, using RCBS case master, and that is where I was measuring. So use the bullet to index, right?
thanks,
Re: Index runout off case neck or bullet?
I think he means that his bullet, neck and case body are all eccentric to each other and wants to know where to measure bullet runout so that he can ignore one eccentricity. My answer to him would be: Measure bullet runout on bullet near neck. Measure neck runout on neck.
I think he means that his bullet, neck and case body are all eccentric to each other and wants to know where to measure bullet runout so that he can ignore one eccentricity. My answer to him would be: Measure bullet runout on bullet near neck. Measure neck runout on neck.
Re: Index runout off case neck or bullet?
No. He is talking about indexing... loading a cartridge so that the "high point" is in the same orientation every time. Generally, up.
The answer is to check the bullet at the ogive. The other answer is that it is probably a waste of time, but who am I to judge?
No. He is talking about indexing... loading a cartridge so that the "high point" is in the same orientation every time. Generally, up.
The answer is to check the bullet at the ogive. The other answer is that it is probably a waste of time, but who am I to judge?
Re: Index runout off case neck or bullet?
There was one study done with bullets that had .007 runout, and fired with and without indexing. There was a significant improvement in group size with indexing. In bullets with .002 runout, indexing showed almost no reward. The study did not mention where the runout was measured, hence my question.
There was one study done with bullets that had .007 runout, and fired with and without indexing. There was a significant improvement in group size with indexing. In bullets with .002 runout, indexing showed almost no reward. The study did not mention where the runout was measured, hence my question.
Re: Index runout off case neck or bullet?
For my handloads, .002 and greater go in the sighter pile. German Salazar is a fan of indexing. I bought a NECO case thickness gauge and permanently marked the thick spot on my cases. I found a very light correlation between the thick spot in the case and the high point on the bullet. I think it was right about 30 - 40% of the time.
What I have found interesting is that when I put different rounds with the same runout together, even if the runout is high, they tend to group together better. It doesn't make sense to me, but it is something I just discovered in the process of separating out "match grade" ammo from practice ammo. I need to do some more tests.
BTW... I have corresponded with German on this and he said that the indexing effect will tend to show up more at a distance and also that it doesn't work with actions with three locking lugs.
I challenged him to actually do a test... but I think he has a lot on his plate right now as he is moving from glass and bipods back into slings and irons.
For my handloads, .002 and greater go in the sighter pile. German Salazar is a fan of indexing. I bought a NECO case thickness gauge and permanently marked the thick spot on my cases. I found a very light correlation between the thick spot in the case and the high point on the bullet. I think it was right about 30 - 40% of the time.
What I have found interesting is that when I put different rounds with the same runout together, even if the runout is high, they tend to group together better. It doesn't make sense to me, but it is something I just discovered in the process of separating out "match grade" ammo from practice ammo. I need to do some more tests.
BTW... I have corresponded with German on this and he said that the indexing effect will tend to show up more at a distance and also that it doesn't work with actions with three locking lugs.
I challenged him to actually do a test... but I think he has a lot on his plate right now as he is moving from glass and bipods back into slings and irons.
Re: Index runout off case neck or bullet?
Seems like less of a pain in the ass to size with a minimum induced runout, which ideally is zero. Use a good bullet, which ideally would have zero runout. And seat using a process that induces a minimum runout, which, of course, would be zero, ideally.
That said, I run typically .001" and less runout, on the bullet halfway from tip to ogive....with no real special effort, or high tech methods.
I used to index cast bullets and it was nothing short of too much bother for the gain.........
Seems like less of a pain in the ass to size with a minimum induced runout, which ideally is zero. Use a good bullet, which ideally would have zero runout. And seat using a process that induces a minimum runout, which, of course, would be zero, ideally.
That said, I run typically .001" and less runout, on the bullet halfway from tip to ogive....with no real special effort, or high tech methods.
I used to index cast bullets and it was nothing short of too much bother for the gain.........
Re: Index runout off case neck or bullet?
Here is German Salazar's article:
http://riflemansjournal.blogspot.com/2010/11/reloading-indexing-cases.html
Here is German Salazar's article:
http://riflemansjournal.blogspot.com/2010/11/reloading-indexing-cases.html
