Why do I keep getting 4-5 thou run out !! I have competition dies, I turn the case several times while seating bullet. Is my press to blame?
Thanks for any input
Lefty
Thanks for any input
Lefty
- Thread starter pengilly
- Start date
Re: Excessive run out.....
Are you measuring COAL? Or from ogive where the seating stem is pushing?
Are you measuring COAL? Or from ogive where the seating stem is pushing?
Re: Excessive run out.....
How are the necks of your brass, pretty concentric, like within .001" thickness from either side? What bullet, just curious? What tool are you using to measure? Ive got the Hornady tool myself. Seating die brand?
How are the necks of your brass, pretty concentric, like within .001" thickness from either side? What bullet, just curious? What tool are you using to measure? Ive got the Hornady tool myself. Seating die brand?
Re: Excessive run out.....
There are many factors that can affect run-out of final loaded cartridges. Some as simple as technique and some as complex as equipment or component alignments.
Technique: If you're just running the ram up and down, you're missing out on a lot. With my entry-level RCBS press I noticed that if I cam-over too hard to where I felt the handle bump solid into the stop, it would induce run-out in that round. With good technique (start the bullet as straight as possible, rotate the case a few times DURING seating (not just at the end), go SLOW, barely cam-over) that my o-give consistency and runout were greatly improved. I was producing runout of .000-.002" in a cheap RCBS press with Redding competition dies and unturned .308 Lapua cases.
Recently I purchased a Redding T7 press and despite my best efforts I was seeing runout of .006-.007". I scratched my head for days wondering what could be going on... Is there too much slop in the rotating head?... Are the die stations perfectly in line with the ram?... Turns out the answer was easier than I expected. I noticed that the shell holder "snapped" into the Redding ram very forcefully compared to my old RCBS press. I removed the snap-ring and instantly runout was back down to within two thousandths and can easily be corrected from there with the Hornady Concentricity gauge. I now use a rubber o-ring around the entire ram to keep the shell holder from falling out and allow the holder to float freely in the press.
The Hornady tool is great for measuring final runout on loaded cartridges but does have its limitations. Some prefer to run the dial indicator on the bullet, others run it on the case. There are several schools of thought on which measurement is the most critical but test your processes using both methods and see what produces the best results for YOU.
A bare-case concentricity gauge is also helpful to check things as the reloading process progresses. Check your fired cases right out of the gun. Check your cases after neck-sizing or full length resizing if that's what you're into. Also, depending on brass quality, check your neck thickness variations.
Unfortunately there may be several of these factors adding into the equation. Experiment with these many factors and you'll likely find the "smoking gun" that is causing your troubles.
My $.02
Tony P.
There are many factors that can affect run-out of final loaded cartridges. Some as simple as technique and some as complex as equipment or component alignments.
Technique: If you're just running the ram up and down, you're missing out on a lot. With my entry-level RCBS press I noticed that if I cam-over too hard to where I felt the handle bump solid into the stop, it would induce run-out in that round. With good technique (start the bullet as straight as possible, rotate the case a few times DURING seating (not just at the end), go SLOW, barely cam-over) that my o-give consistency and runout were greatly improved. I was producing runout of .000-.002" in a cheap RCBS press with Redding competition dies and unturned .308 Lapua cases.
Recently I purchased a Redding T7 press and despite my best efforts I was seeing runout of .006-.007". I scratched my head for days wondering what could be going on... Is there too much slop in the rotating head?... Are the die stations perfectly in line with the ram?... Turns out the answer was easier than I expected. I noticed that the shell holder "snapped" into the Redding ram very forcefully compared to my old RCBS press. I removed the snap-ring and instantly runout was back down to within two thousandths and can easily be corrected from there with the Hornady Concentricity gauge. I now use a rubber o-ring around the entire ram to keep the shell holder from falling out and allow the holder to float freely in the press.
The Hornady tool is great for measuring final runout on loaded cartridges but does have its limitations. Some prefer to run the dial indicator on the bullet, others run it on the case. There are several schools of thought on which measurement is the most critical but test your processes using both methods and see what produces the best results for YOU.
A bare-case concentricity gauge is also helpful to check things as the reloading process progresses. Check your fired cases right out of the gun. Check your cases after neck-sizing or full length resizing if that's what you're into. Also, depending on brass quality, check your neck thickness variations.
Unfortunately there may be several of these factors adding into the equation. Experiment with these many factors and you'll likely find the "smoking gun" that is causing your troubles.
My $.02
Tony P.
Re: Excessive run out.....
couldnt have said it better myself.. couple of those I am going to have to try.. !!! thanks
couldnt have said it better myself.. couple of those I am going to have to try.. !!! thanks
Re: Excessive run out.....
I can't tell you what you need to do to reduce runout but ammo is made in the dies. All the press can do is push the case into and pull it back out of the dies and they all do that.
Most bullet runout comes from poor case necks. Poor case necks usually come from case manufactoring methods and/or the neck expander used to reload. Excessive 'neck tension' also makes seating require more force than should be needed and that frequently produces runout. The seating plug in threaded dies is too loosely fitted for seating and turning to make much difference, if a bullet starts in slanted it will usually stay slanted.
If your 'competition dies' are Forster or Redding, the seaters are good but even they can't seat bullets straight in bad necks.
I can't tell you what you need to do to reduce runout but ammo is made in the dies. All the press can do is push the case into and pull it back out of the dies and they all do that.
Most bullet runout comes from poor case necks. Poor case necks usually come from case manufactoring methods and/or the neck expander used to reload. Excessive 'neck tension' also makes seating require more force than should be needed and that frequently produces runout. The seating plug in threaded dies is too loosely fitted for seating and turning to make much difference, if a bullet starts in slanted it will usually stay slanted.
If your 'competition dies' are Forster or Redding, the seaters are good but even they can't seat bullets straight in bad necks.
Re: Excessive run out.....
Are you turning your necks. You would be surprised.
Are you turning your necks. You would be surprised.
Re: Excessive run out.....
Great info to try
Thank you
Jeff
Oh, no I'm not neck turning but I did go all the way down to the stop forcefully
I'll keep tryin !
I'm using a dial indicator on a concentricity gauge
Great info to try
Thank you
Jeff
Oh, no I'm not neck turning but I did go all the way down to the stop forcefully
I'll keep tryin !
I'm using a dial indicator on a concentricity gauge
Re: Excessive run out.....
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">I can't tell you what you need to do to reduce runout but ammo is made in the dies. All the press can do is push the case into and pull it back out of the dies and they all do that.
Most bullet runout comes from poor case necks. Poor case necks usually come from case manufactoring methods and/or the neck expander used to reload. Excessive 'neck tension' also makes seating require more force than should be needed and that frequently produces runout. The seating plug in threaded dies is too loosely fitted for seating and turning to make much difference, if a bullet starts in slanted it will usually stay slanted.
If your 'competition dies' are Forster or Redding, the seaters are good but even they can't seat bullets straight in bad necks.</div></div>
It could be other things like a dirty seating plug, too much compression, or some other factor. I was getting little pieces of crap on the case head that was causing the case to go into the press crooked at one point. It had snuck into my loading tray. Took me a while to figure out. That said, 4 - 5 thou is quite a bit. I think more than can be explained by uneven case necks.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">I can't tell you what you need to do to reduce runout but ammo is made in the dies. All the press can do is push the case into and pull it back out of the dies and they all do that.
Most bullet runout comes from poor case necks. Poor case necks usually come from case manufactoring methods and/or the neck expander used to reload. Excessive 'neck tension' also makes seating require more force than should be needed and that frequently produces runout. The seating plug in threaded dies is too loosely fitted for seating and turning to make much difference, if a bullet starts in slanted it will usually stay slanted.
If your 'competition dies' are Forster or Redding, the seaters are good but even they can't seat bullets straight in bad necks.</div></div>
It could be other things like a dirty seating plug, too much compression, or some other factor. I was getting little pieces of crap on the case head that was causing the case to go into the press crooked at one point. It had snuck into my loading tray. Took me a while to figure out. That said, 4 - 5 thou is quite a bit. I think more than can be explained by uneven case necks.
Re: Excessive run out.....
Great info, guys, thanks.
Great info, guys, thanks.
Re: Excessive run out.....
When seating the bullet I turn the case as it goes interference the seater die. Worked wonders fake me. Went from 4 to 5 thou runout to negligible.
When seating the bullet I turn the case as it goes interference the seater die. Worked wonders fake me. Went from 4 to 5 thou runout to negligible.
Re: Excessive run out.....
I'd start by checking your runout on your cases right out of the chamber after firing. Check the body, then measure on the neck. shouldnt have more than .001" TIR..
Size a round then measure again. Does your runout worsen? How much?
Then seat a bullet, measure again.
Do this with a few pieces of brass and see if you can isolate which step in your process is inducing the runout....
Uneven neck thickness (neck turning can help)
Poor die to brass fit in your seater (lack of case support when seating)
Poor seating stem to bullet fit
Out of round chamber
Sizing die out of round (yes, I've seen it happen)
Sizing your necks down in greater than .005" increments wih bushing dies
Excessive seating pressure from highly compressed loads, or too much "neck tension.
Measuring tool device isn't working properly. (Not as likely but possible)
I'm sure there's a few more possibilities that I've left out...
Bottom line... What's the on target results???
I'd start by checking your runout on your cases right out of the chamber after firing. Check the body, then measure on the neck. shouldnt have more than .001" TIR..
Size a round then measure again. Does your runout worsen? How much?
Then seat a bullet, measure again.
Do this with a few pieces of brass and see if you can isolate which step in your process is inducing the runout....
Uneven neck thickness (neck turning can help)
Poor die to brass fit in your seater (lack of case support when seating)
Poor seating stem to bullet fit
Out of round chamber
Sizing die out of round (yes, I've seen it happen)
Sizing your necks down in greater than .005" increments wih bushing dies
Excessive seating pressure from highly compressed loads, or too much "neck tension.
Measuring tool device isn't working properly. (Not as likely but possible)
I'm sure there's a few more possibilities that I've left out...
Bottom line... What's the on target results???
Re: Excessive run out.....
Gotta take the slop out of the threads when setting up both your seating die and sizer. A washer or two laid across the shell holder with the ram up then tighten the die down until it touches the washers and set the lock ring.
Gotta take the slop out of the threads when setting up both your seating die and sizer. A washer or two laid across the shell holder with the ram up then tighten the die down until it touches the washers and set the lock ring.
Re: Excessive run out.....
I found that much of the runout I was experiencing was caused by the expander ball in my sizing dies. I started using a Lee collet neck sizing die for the neck (which uses a mandrel), and a Redding body sizing die to bump the shoulders, and this solved the problem.
I found that much of the runout I was experiencing was caused by the expander ball in my sizing dies. I started using a Lee collet neck sizing die for the neck (which uses a mandrel), and a Redding body sizing die to bump the shoulders, and this solved the problem.
Glad I found this thread (on accident). Good timing for my .223 runout problems. Good things to investigate outlined above. Could insufficient lube inside the neck cause some (or all) of this? I admit I do a poor job of lubing for the expander ball.
Similar threads
