I am getting inconsistent and visibly wobbly bullets with my new brass. New Lapua 6.5 Creedmoor brass, prepped as follows: case mouths lubed and expanded with 21st Century TiN expander mandrel, neck mouths vld chamfered on LE Wilson hand case lathe, necks deburred with Forster deburring tool, primers installed with 21st Century hand primer, powder added with the V3 autotrickler, Hornady 153 grain Atips seated to a COAL of 2.950" using a LE Wilson micrometer seater and K&M arbor press. I also tried my Forster micrometer seater die in my CoAx with the same result. Out of fifty rounds, perhaps five have no visible runout at the tip. I have the Accuracy One concentricity gauge as well. Measured just beyond the case mouth, I am getting 2-4 thousandths runout, and it gets progressively worse towards the tip of the bullets. I simply don't know what is causing this.
Need Help With Bullet Runout
- Thread starter BerndV
- Start date
Usually a runout condition is a fault of the brass and/or the sizing die. Most sizing dies center the neck from the outside. If the necks is thicker on one side than the other you get runout or more runout. Lapua is good brass but not perfect. If you turn the necks enough to get at least 75% coverage, then resize, it may cure the problem.
I had 200 pieces of new Hornady brass all the same lot number. I ran them through the sizing die and had sometimes .008" - .010 runout on the necks. I fired a few and one side of the neck was clean, the other had soot. So I neck turned some, resized and rechecked and still had an average of .006" -.007" runout on a clean smooth surface. OK, next step was to anneal them all, resize again and this time they ranged from .002" - .004" with maybe 10% at or under .001". About half were at .004" but none any more than that. I made a friend a gift of the ones over .0025". These also averaged 7% more internal volume. Firing them did help. No more Hornady brass!
I check my rounds half way from the neck to the tip and I'm happy with .001" which over half is, and another 25-30% will read at or under .002". The others I keep for warm up and fouling shots.
I had 200 pieces of new Hornady brass all the same lot number. I ran them through the sizing die and had sometimes .008" - .010 runout on the necks. I fired a few and one side of the neck was clean, the other had soot. So I neck turned some, resized and rechecked and still had an average of .006" -.007" runout on a clean smooth surface. OK, next step was to anneal them all, resize again and this time they ranged from .002" - .004" with maybe 10% at or under .001". About half were at .004" but none any more than that. I made a friend a gift of the ones over .0025". These also averaged 7% more internal volume. Firing them did help. No more Hornady brass!
I check my rounds half way from the neck to the tip and I'm happy with .001" which over half is, and another 25-30% will read at or under .002". The others I keep for warm up and fouling shots.
I use the expander mandrel to obtain the desired neck tension on my new brass. Out of the fifty referenced in this thread, all were hand selected for runout of less than 0.0015 as measured in the center of the inside of the neck with my Accuracy One concentricity gauge after the prep work was completed.
Straightshooter1
Gold $$ Contributor
I've had the same runout problem when loading NEW unfired Lapua brass (as much as .008 - 010 runout). The problem went away after 1X firing and a FL sizing.
You can use the expander ball in the Forster die. It is rubber mounted with loose threads and won't pull the necks out of place. The nest way to set it is to run a case fully into the die. Back out the ball and shaft until you feel it lightly touch. Then turn in about 1/2 to 2/3 turn. This will keep most of the neck in the neck portion of the die while the ball is being pulled through keeping perfect alignment. Be sure to lock the adjustment. If the ball is too high, it will lock up the die.
jepp2
Gold $$ Contributor
Assuming you aren't flash hole size limited in using the LCD, this will give you the straightest case necks and correct any factory induced runout.
Ned Ludd
Silver $$ Contributor
I've had the best results with virgin brass using an oversized expander mandrel (~.001" over bullet diameter) first, to open up all the necks to some minimum diameter greater than the bushing I intend to use. The cases are first sprayed liberally inside and outside the neck/body with Hornady One-Shot lube. I use the following mandrels/Gen II die setup:
https://www.sinclairintl.com/reload...inless-steel-expander-mandrels-prod33134.aspx https://www.sinclairintl.com/reload...inless-steel-expander-mandrels-prod33134.aspx).
Next, I size all the cases back down with the appropriate FL bushing die. I typically select a bushing to give ~.002" neck tension (interference fit). [Note - I remove the expander ball from all my sizing dies, due to the potential for the exact issue you're describing]. The cases are then cleaned
I have found that the neck diameter of virgin brass can vary quite a bit straight out of the box. The expander mandrel opens up all the necks to some minimum diameter that is larger than the bushing, then the FL/bushing die re-sizing process brings them back down to a more uniform diameter. This process does not move the shoulder detectably. Finally, it is not necessary to use the OS expander mandrel step once the brass has been fire-formed, as the necks will open up noticeably to match the chamber upon the first firing.
The main reason for this process is to get better and more consistent performance out of virgin brass. I don't like the idea of putting a bunch of rounds into the dirt just to fire-form brass, getting little else in return. I have no qualms about using virgin brass prepped as described above in local F-TR club matches, and it has performed quite well in that regard. Whether this application would be appropriate for the most demanding accuracy/precision requirements in a discipline such as BR is questionable. Nonetheless, it works for my purposes. Once the all brass has been fire-formed, the load will have to be tweaked to bring it back into tune. Nonetheless, I get good use out of virgin brass with this approach, and gain some useful information about what a specific rifle "wants" during the process.
The most important point about this procedure is that I don't typically ever see runout of more than .001" to .0015". Cases prepped in this way have very straight necks. In order to correct a runout problem, it's easier to identify the source of the problem, or particular step in which it occurs, as a first step. Then you can correct it. Otherwise, you are guessing, then possibly changing a bunch of things and hoping the problem goes away. It sounds like you are doing the right things. Checking runout at the case neck after each step, and then again once the bullets are seated should allow you to identify the point at which the runout has been introduced. As I mentioned previously, the use of the expander ball in a sizing die has often been associated with runout. That is not to say that the expander ball must be a problem, many use them without issue. Nonetheless, I routinely remove them as soon as I get a new die because I haven't found them to add any benefit to my brass prep procedure, and I don't want the potential for any runout issues. YMMV.
One other thing worth mention is that when you use a mandrel and/or a bushing die for neck prep, it is critical that both the mandrel and bushing are adjusted to be "free-floating" as indicated in the manufacturer's instructions. If either one is too tight, or "locked down" in the die in a manner that is not perfectly aligned, runout will be the likely result. Finally, although it wouldn't typically be my first call, it is possible to get a bad or misaligned die. For example, if you were to identify a seating die as the suspect point the reloading process [hypothetically] through stepwise runout analysis, and have removed the expander ball and also checked to make certain that the bushing has been properly free-floated, and the die mounted correctly, then I would probably give the die manufacturer a call to see what they recommend, whether that be replacement, or possibly an adjustment or doing some step in a particular way.
Was it fired? you are wasting your time if not. ...... jim
Dusty Stevens
Shiner
You must fl size them and fire them before you worry
So it sounds like concerning myself with bullet runout with new brass is a waste of time. However, as Ned stated above, firing a couple hundred rounds for no reason other than to fire form the brass has always seemed rather wasteful. I guess the reason I started this thread was to determine how to get the best accuracy and consistency out of new brass. I am getting SD's in the 3-5 range on this new brass, but the precision is a bit hit or miss and the variable seems to be the bullet runout. If I hand select the ones with minimal runout, I'm getting bugholes. The rest is 1/2 to 3/4 moa.
A full length die will hold the case body and neck in concentric alignment when sized
And a expander die does not hold the case body and neck in concentric alignment.
If you do not like a standard expander in a full length die then remove the dies expander and expand the neck with a expander die.
Meaning if the new cases have neck runout the expander die will not align the neck with the case body.
And a expander die does not hold the case body and neck in concentric alignment.
If you do not like a standard expander in a full length die then remove the dies expander and expand the neck with a expander die.
Meaning if the new cases have neck runout the expander die will not align the neck with the case body.
Ned Ludd
Silver $$ Contributor
Based on your cartridge of choice, I'm going to assume you're not pursuing a BR application. Based on that assumption, I can tell you with absolute certainty that it's not a waste of time to prep virgin brass necks carefully for use in F-Class matches. In fact, I've won more a few matches using virgin brass prepped as I described above, which is something F-Class shooters unaware of such approaches for prepping virgin brass might never even consider trying. I know a few other F-Class shooters that can tell you the same thing. The approach used has to fit the shooting application. Obviously, there is a great deal of overlap among different disciplines in terms of successful approaches used to reload ammunition for precision shooting, but there are some differences as well. What works for one application is not necessarily optimal, or even desirable, for a different application.
bozo699
Gold $$ Contributor
BerndV,
When your sizing have you tried sizing most of the way then rotate 180 and finish your sizing stroke? Then when seating seat about half way then rotate 180 and finish seating? I would check brass neck runout on out of the box brass and check it again with each step. Have you checked your bullets themselves for runout, I have ran into some bad ones.
Have you checked your seating stem to see if its indexing off your ojive or just on the plastic tip of the bullet? I had some custom ones made for me several years ago for my dasher and Brx that worked much better. There are many other factors but I would do as Jim said and check from the start and find which process is inducing the runout.
Wayne.
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