Back when I was wearing out 7.62 NATO Garand barrels shooting matches, I often checked M118 match ammo for bullet runout. That arsenal match ammo often had rounds in some lots that ran as much as 7 to 8 thousandths runout. Using a .338" bullet puller collet to hold live round's case neck indexed to the high point, I would bend them back straight pushing on the case head. 'Twas easy to get runout down under 2 thousandts. 600 yard accuracy went from about 1.5 MOA down to about .6 MOA. Did the same thing with government issued .30-.338 Win. Mag. ammo from the marksmanship unit. Well worth the effort to do so in my opinion.
Bullet runout what is the max?
- Thread starter Kaboom
- Start date
Help Support Long Range Hunting Forum
rscott5028
Well-Known Member
Perhaps Hornady has improved the quality of their guages since I bought mine? Mine has measurable slop. But, I've heard similar comments from others and have checked several at stores and at DSC. All the ones I've handled had slop in them.
Charlie's may be better than mine and it appears that his reads in tenths. Or, perhaps a typo?
Nonetheless, it all goes back to Bart's point. i.e. you'll get different readings depending on how you hold the cartridge and where you measure
The Hornady method supporting the cartrdge between the case head and bullet tip is flawed IMHO.
-- richard
rscott5028
Well-Known Member
Bart - A feller's gotta do what's necessary with the tools at his disposal.
I bought the Hornady for the sole purpose of straightening ammo back before I got a Forester Coax and an arbor press. I never recall anything 8-10 thou TIR. If I had anything like that it would've gone straight to the oil buck. So, I can't speak to that. But, bending from .003-.004 down to .001 or less was a waste of time in my experience as it did not statistically alter my results.
I hope the competition this weekend is spending their efforts bending case necks while I make mine straight right from the start.
-- richard
dieseldoc
Well-Known Member
Bart - A feller's gotta do what's necessary with the tools at his disposal.
I bought the Hornady for the sole purpose of straightening ammo back before I got a Forester Coax and an arbor press. I never recall anything 8-10 thou TIR. If I had anything like that it would've gone straight to the oil buck. So, I can't speak to that. But, bending from .003-.004 down to .001 or less was a waste of time in my experience as it did not statistically alter my results.
I hope the competition this weekend is spending their efforts bending case necks while I make mine straight right from the start.
-- richard
First of all, I agree that the most important item is to produce .00015 run reloads and that is my standard. With Redding comp dies and Redding T-7 press is where I get the best results.
The point was miss on moving bullets, This was done to test the results of excessive run out.
Charlie
1.5 ten-thousandths runout? That's about 1/7th of one-thousandths of an inch.
How much do your groups open up if bullet runout's 2 to 3 ten-thousandths or .00020 to .00030 inch?
If you and your hardware shoot well enough to do that, you've got the most accurate rifle, ammo and shooter combination on this planet.
Change the above to:
jlvandersnick
Well-Known Member
could someone please explain to me what "runout" means.
Thanks
Jerry
Thanks
Jerry
Bullet runout is a measurement of the cartridge case long axis to the bullet's long axis. It's typically measured in thousandths of an inch. With the cartridge case resting in a V block or groove, it's spun with a dial indicator just behind the bullet's tip. As the bullet tip is typically a tiny bit off the case axis, the amount will be indicated by the dial indicator.
Here's a picture of one, others will vary in their design and features:
jlvandersnick
Well-Known Member
Thanks Bart B
Now I see what all of the fuss is about
Jerry
Now I see what all of the fuss is about
Jerry
It is when the bullet's longitudinal center line, or axis does not match the centerline of the case. The amount that the bullet is "cocked" is measured in thousandths of an inch.
I know this thread is about acc. but has anyone had a 1/2" or better group with 5 shots and then #6 runs out to 2". went thru my reloading sequence, could'nt find any thing wrong. have done this with rem. win. and fed. brass, the fliers were with rem and win never with fed. got to isolating the individual cases after depriming, which i do before sizing and found that the fliers had flash holes that were .082 made myself a probe to within .0815 and any case with a flash hole that lets the probe drop in i discard, no more fliers. just something to watch out for guys, also the pressure was up there with that particular case. it helped me, i asked bo clerke about this and he assured me that pressure would really be up there with my handloads which are on the hot side to begin with. 30-06 AI driving 190. horn interlks @ 2970fps,changing to a 180. horn interlk and l.o.a same powder charge 3022fps, used fed 215 primers. by the way any body know why there is a shortage of fed 215??? hope this helps some one. winchester cases are between 15 to 16 grains lighter than rem or fed. in the 06 cases i adjust my charge accordingly. good shooting hermanos. william.
[QUOTE with a dial indicator just behind the bullet's tip. As the bullet tip is typically a tiny bit off the case axis, the amount will be indicated by the dial indicator."
Bart - the indicator should rest at the ogive, not on the tip (meplat). You want to obtain TIR on the bearing surface.
Bart - the indicator should rest at the ogive, not on the tip (meplat). You want to obtain TIR on the bearing surface.
I know that. Which is why I stated:
it's spun with a dial indicator just behind the bullet's tip.
My dial indicator's touching the ogive just behind the tip; typically 1/10th inch behind it.
Mikecr
Well-Known Member
Gene, an 'ogive' is not a particular place on a bullet nose.
Bart described a place furthest forward on the nose that still provides good readings.
No standard place on the nose is associated with bearing, or even leade contact, as this varies with local factors like leade angle, and ogive radius & type.
Also, ammo axis, to any centerline, really does not correlate directly with TIR.
Runout is not eccentricity. They are different things.
Bart described a place furthest forward on the nose that still provides good readings.
No standard place on the nose is associated with bearing, or even leade contact, as this varies with local factors like leade angle, and ogive radius & type.
Also, ammo axis, to any centerline, really does not correlate directly with TIR.
Runout is not eccentricity. They are different things.
