I am new to the precision reloading game so please excuse me if this is a stupid question but this subject, and how to ensure it, is killing me. Two my way of thinking there are two types of non-concentricity. A bullet can be tilted in the neck. This would be due to having the area at the top of the neck thicker than the bottom and the opposite condition on the other side of the neck. Or it could be off axis if one side of the neck is thicker than the other. Now, I can't understand how tools that are meant to fix this problem actually work. In the case of the "off-axis" bullet: pulling or pushing the ogive/meplat into place would only cause "tilting" of the bullet. Hence, if a "tilted" bullet is pulled or pushed to get its's tip into place then isn't the base of the bullet doing the oposite? The "gap" (or less supportive area)left in base of the neck where the bullet was forced from would only allow the bullet to tilt once again upon firing, and, in this condition, are we not also affecting neck tension? This is why, to my way of thinking, the Lee collet dies would be the way to go. They maintain the axis concentricity of the fire formed case but would they not also help even out the neck wall thickness some. Maybe "working" the brass into uniform thickness? Am I over thinking this? Please help save my sanity!
Stuck on bullet runout
- Thread starter jambau
- Start date
Re: Stuck on bullet runout
First you fix the case-neck so that is does not have appreciable run out
Then you seat the bullet with a die that seats the bullets without minimal runout (like a Redding Competition seater die).
Trouble starts above 0.003" RO, so if you get RO this small, you are golden.
Bending the seated bullet in a cartrige is like applyinig a cast to the still broken arm.
First you fix the case-neck so that is does not have appreciable run out
Then you seat the bullet with a die that seats the bullets without minimal runout (like a Redding Competition seater die).
Trouble starts above 0.003" RO, so if you get RO this small, you are golden.
Bending the seated bullet in a cartrige is like applyinig a cast to the still broken arm.
Re: Stuck on bullet runout
Run out problems are best solved by using quaility components that have been built to the tightest standards for that equipment.
Press rams must be perfect and true. Dies must also be perfect. The alignment between the die and the ram must be true. The shell holder must also be of good build.
Then you need to have brass that is good quality.
My understanding is that a high quality action, or a trued action will help in that fired brass should be coming out true as well.
Did i just use the word true too many times?
Run out problems are best solved by using quaility components that have been built to the tightest standards for that equipment.
Press rams must be perfect and true. Dies must also be perfect. The alignment between the die and the ram must be true. The shell holder must also be of good build.
Then you need to have brass that is good quality.
My understanding is that a high quality action, or a trued action will help in that fired brass should be coming out true as well.
Did i just use the word true too many times?
Re: Stuck on bullet runout
Forster dies are top quality.
Not only is the ultraseater a fine addition, but the Forster FL sizers have an easy expander ball.
This Forster expander, in comparison to an RCBS expander, in my opinion is worlds apart! The forster just glides out of cases with ease... the RCBS requires more force.
Forster dies are top quality.
Not only is the ultraseater a fine addition, but the Forster FL sizers have an easy expander ball.
This Forster expander, in comparison to an RCBS expander, in my opinion is worlds apart! The forster just glides out of cases with ease... the RCBS requires more force.
Re: Stuck on bullet runout
What I do, is fireform all brass. Then measure runout. There should be .001 to no runout at all. Assuming you seperated cases by weight and neck wall thickness, you would expand them and turn them. This makes it so the neck walls are perfect(in thoery). Measure runout after every step so you know which step is causing the runout. Usually when you turn to a predetermined thickness, which is 100% of the neck, you wont have too many runout problems. If you are turning, make sure you turn just a dollhair into the shoulder to eliminate any ridges inside the neck. Assuming no other step is causing runout, seat the bullet. I have read by multiple sources that you should seat the bullet halfway, then turn the case 1/2 turn and complete the seating process. This helps with runout. Theres a little more too it but these are the basics. You can get good runout without turning, but I don't even bother unless I turn.
What I do, is fireform all brass. Then measure runout. There should be .001 to no runout at all. Assuming you seperated cases by weight and neck wall thickness, you would expand them and turn them. This makes it so the neck walls are perfect(in thoery). Measure runout after every step so you know which step is causing the runout. Usually when you turn to a predetermined thickness, which is 100% of the neck, you wont have too many runout problems. If you are turning, make sure you turn just a dollhair into the shoulder to eliminate any ridges inside the neck. Assuming no other step is causing runout, seat the bullet. I have read by multiple sources that you should seat the bullet halfway, then turn the case 1/2 turn and complete the seating process. This helps with runout. Theres a little more too it but these are the basics. You can get good runout without turning, but I don't even bother unless I turn.
Re: Stuck on bullet runout
Tikka, you are correct about the case necks, no seater can do a thing 'bout bent necks! You MUST have a concentricity gage to identify the runout or lack of it. (Sinclair)
My method is to fire new brass and neck size it with a Lee collet neck die so the mandrel can make the inside about as concentric as I can expect. (A conventional sizer's expander ball usually pulls necks out of line to some degree.) Then I neck turn to even the outside to better match the inside (Forster HOT-100).
Since factory cases have thin necks anyway, thinning them just makes a sloppy fit worse. I only skim turn so maybe 60-80% of the circumference is skint a little. Load and fire the processed cases, load again(Forster BR seater) and check for bullet runout. If it's not 2 thou TIR or less I pull the bullet/powder and toss that case. A typical case loss rate for Rem/Win brass is around 15% of the total but what's left is pretty straight. I agree that trying to bend a crooked round straight with some magic tool is working from the wrong direction.
You need to understand that TIR (Total Indicated Runout) is the same error measured from both directions so the actual bullet tilt is half of the TIR. And measure the TIR at the worst possible place so you get the real tilt, doing this test at the half-way point of the bullet ogive makes the reading appear less but you would be kidding yourself about your actual runout.
Tikka, you are correct about the case necks, no seater can do a thing 'bout bent necks! You MUST have a concentricity gage to identify the runout or lack of it. (Sinclair)
My method is to fire new brass and neck size it with a Lee collet neck die so the mandrel can make the inside about as concentric as I can expect. (A conventional sizer's expander ball usually pulls necks out of line to some degree.) Then I neck turn to even the outside to better match the inside (Forster HOT-100).
Since factory cases have thin necks anyway, thinning them just makes a sloppy fit worse. I only skim turn so maybe 60-80% of the circumference is skint a little. Load and fire the processed cases, load again(Forster BR seater) and check for bullet runout. If it's not 2 thou TIR or less I pull the bullet/powder and toss that case. A typical case loss rate for Rem/Win brass is around 15% of the total but what's left is pretty straight. I agree that trying to bend a crooked round straight with some magic tool is working from the wrong direction.
You need to understand that TIR (Total Indicated Runout) is the same error measured from both directions so the actual bullet tilt is half of the TIR. And measure the TIR at the worst possible place so you get the real tilt, doing this test at the half-way point of the bullet ogive makes the reading appear less but you would be kidding yourself about your actual runout.
Re: Stuck on bullet runout
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tikka09</div><div class="ubbcode-body">How do you fix the case? </div></div>
Use dies without an expander ball.
Use dies that support the case body while sizing the neck.
Size clean cases.
When setting up dies, use an oring between the die nut and the press thread to allow the die to self center on the ram.
Use the nerve ending in the arm use to depress the lever on the press. These can tell you a lot about the sizing operation in progress if you just listen.
Measure, measure, measure, until you find the culpret. Then fix the crap out of it.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tikka09</div><div class="ubbcode-body">How do you fix the case? </div></div>
Use dies without an expander ball.
Use dies that support the case body while sizing the neck.
Size clean cases.
When setting up dies, use an oring between the die nut and the press thread to allow the die to self center on the ram.
Use the nerve ending in the arm use to depress the lever on the press. These can tell you a lot about the sizing operation in progress if you just listen.
Measure, measure, measure, until you find the culpret. Then fix the crap out of it.
Re: Stuck on bullet runout
I have a runout problem to from time to time...My ejector plunger spring is so strong that when I cycle the bolt the ejecting brass slaps the inside of the receiver right on the neck...At this point what do I do? I use a set of redding competition dies so for the sake of consistency how do it get the dent out properly to size it down with neck bushing...I am guilty of just marking it, sizin it, and just jammin a bullet down its throat using them as foulers...also i dont do much rough cycling just gently getting it to that point and holding it back with my finger to prevent the "slap"...Maybe i could cut down the ejector spring too? Thanks for listening to me ramble...
I have a runout problem to from time to time...My ejector plunger spring is so strong that when I cycle the bolt the ejecting brass slaps the inside of the receiver right on the neck...At this point what do I do? I use a set of redding competition dies so for the sake of consistency how do it get the dent out properly to size it down with neck bushing...I am guilty of just marking it, sizin it, and just jammin a bullet down its throat using them as foulers...also i dont do much rough cycling just gently getting it to that point and holding it back with my finger to prevent the "slap"...Maybe i could cut down the ejector spring too? Thanks for listening to me ramble...
Re: Stuck on bullet runout
I have had some bullet concentricity issues in the past and still struggle from time to time. My 6.5 Grendel always seemed to have .005-.008 of bullet runout and still shot well, but I knew it could do better.
I found out the the bullets with a steeper angle on the boat tail seemed to have more run out. While bullets like the Sierra 123 MK had a long boat tail measured much less run out.
Also, if your neck of the brass is blowing out during firing, then your sizing it back down, then your expanding it when seating the bullet, you will get lots of run out and other issues.
I measure the chamber neck, measure the loaded neck O.D. and then choose a bushing that gives me the proper neck tension so I'm not oversizing my brass and then expanding it more than I should when seating.
I'm currently using a Forester Co-Ax press and I have a Redding Big Boss on the way. I will do a side by side comparison when they get in to see if one design is better. I still get runout from time to time.
Mark
I have had some bullet concentricity issues in the past and still struggle from time to time. My 6.5 Grendel always seemed to have .005-.008 of bullet runout and still shot well, but I knew it could do better.
I found out the the bullets with a steeper angle on the boat tail seemed to have more run out. While bullets like the Sierra 123 MK had a long boat tail measured much less run out.
Also, if your neck of the brass is blowing out during firing, then your sizing it back down, then your expanding it when seating the bullet, you will get lots of run out and other issues.
I measure the chamber neck, measure the loaded neck O.D. and then choose a bushing that gives me the proper neck tension so I'm not oversizing my brass and then expanding it more than I should when seating.
I'm currently using a Forester Co-Ax press and I have a Redding Big Boss on the way. I will do a side by side comparison when they get in to see if one design is better. I still get runout from time to time.
Mark
