I have struggled lately with bullet runout. I have followed all the suggestions. I rotate the shell about 5 times while seating a bullet. I deprime separately and raise my expander ball to the top when FL sizing. This produces 1.5mil or less brass neck runout. Which I can deal with. I square up my sizing and seating dies by putting pressure on them with my piston before locking my locknut. I then buy this 70 dollar Redding seating die. I think I have better luck with my RCBS seating die, not really. Even though this redding will set you COL dead nuts on. Pretty cool.



But while loading 20 190gr matchkings for my 300RUM last night, 7 out of 20 has runout around 4 mil. The other 13 is 2mil or less. I not even sure it even matters much. I just want nice little 5 shot groups at 200 yards. I get this nice 3 bullet cluster about .5" then 2" low at 200 yards. I get this ugly flyer. I know I am really picking pepper out of ant $hit, but I want to compete one day.



I know I am being anal about all this, but I really like to move aside anything that can put doubt in my mind. Right now, I thinking the runout if causing me these flyers one out of 4 shots. If I take that doubt out, I can correct what really is causing me issues.



Loaded 20 more Triple X last night. About the same story 10 out of 20 bad runout with greater than 6mil. Seems its critical during the initial seating. Not sure what else to try. Maybe my shell holder? It does seem to float a little on the piston. Maybe try RCBS competition die? Maybe that 1.5 mil brass neck runout causes the bullet to insert wrong sometimes making 5 to 7 mil runout on bullet near the ogive. I mean its hard to correct for 1.5 mil brass runout.

bigcountry:

I am a little confused by your use of the word "mil" as in 2 mil, 4mil, etc. It may be me but I think you mean .002, or.004 which is thousanths. I'm not picking here but I just want to be sure. If I'm making the right assumption you may find that turning your case necks just enough to clean them up will help correct this run-out. Also, I use Wilson straight line seating dies. They pretty much solved this problem, at least on small cases, for me.

knobmtn

Yea, 2 mil=.002"

Bigcountry: Is there runout on a fired case? I would neck size with a fire formed case. You have a very good seating die in the Redding Comp.....you may need the rest of the set, the Redding Comp Neck sizer and a body die. Use the titanium bushings. Size depends on your brass, but in a fired .308 case, Lapua brand, I first size the neck with a .339 then again with a .335. The numbers may not be the same for the .300, but the sequence will work better than just turning the brass. Gurus tell us that trying to neck size too much on one stroke induces runout, hence the two step procedure. Good luck....I don't think you can buy better dies than Redding or Wilson without going custom. Just my 2 cents worth!

I cut my runout in half with a really good bevel on the inside of my brass. After trimming, go a little extra with a beveling tool so the bullet wants to sit straight before seating.

FWIW, I still get .005-.008 runout routinely due to (I think) a loose, worn out press. I have measured and measured, but can't seem to correlate the high runout rounds to the ugly flyers, so don't put all your energy into that one place to improve your loading.

Turning necks makes a huge difference. I trim the high spots (60-70%) of the neck is shiny aftet turning. I get a variance of about .0002-.0005" at 4 corners of the neck after this.

Second,..definitly use the chamforing tool and cut a good angle in the mouth,...as has been stated, the bullet seats straighter.

Also,..too much neck tension makes for unconcentric seating. The turning of the necks will help to reduce the neck tension a little at a time,..as well as to keep it nice and uniform. Or you can use the bushing dies to change neck tension,..but turning plays a big role IMHO.

The unanswered question is whether this small amount of runout has anything to do with your flyers.

Are you allowing plenty of cooldown time between shots?

Were I you, I would see that darn runout rig. It is making a neurotic out of you! Here is what to do.

1. Turn the necks to make shure they are uniform
2. Use a straight line bullet seat (I use Vickerman and Wilson.

If you are still getting flyers you feel are coming from runout, you have either bad sizing dies or a crooked chamber in your rifle. All the handloading in the world won't compensate for a chamber that is not dead straight with the bore. Oval chambers are also a no..no.

Ok, to answer. I have measured several cases after fired. Very staight from the body to the neck.

Cooldown? Well, I usually shoot a 3 shot group one after another. It is a heavy barrled gun and figured it should be able to handle a 3 shot run before cooling. But I hear ya, and will try it.


JustC, I was thinking of that but have never turned necks before. I always heard they cause more trouble than worth. reason I was thinking of that is my brass necks after loading only has .0015" runout, but if you scoot up on the bullet right after the neck, it has .005". So that must be neck chamfering or neck thickness problem. I will look into this.

I use a wilson deburring tool to chamfer. I might be a little sloppy with it. Look further into this also.

Thanks guys.

bigcountry:

Chargar and I are defintely on the same page. Read his post carefully. And then go back up and read my earlier post. Here's something you can try in your next range session. Segregate your cases. Take a group with approximately the same amount of runout and index them. Put a small file mark back on the rim to corresspond to high spot on the neck. Shoot them seperatly from the other loaded rounds. When you place them in the chamber use the index mark to be sure the high spot is in the same place for each round. In other words, place the index mark (high side) at 12 o'clock. Or wherever you want just so all go with the index mark the same. See if that helps. This isn't really a fix. It may just help with your diagnostics.

knobmtn

My suggestion is to try the Lee collet neck die. With this die I rarely if ever have runout more than .002". I use this die in conjunction with a Forster Ultra seater and I've been very happy. If you must full length size, then I agree with others who say that you might want to try neck turning.

bigcountry,
1. measure run-out on fired case
2. measure run-out after sizing case.if more run-out is detected remove expander ball and re-size another fired case(not the one you just sized) and again measure run-out. this should tell if it is the sizer die that is causing the trouble and if the die is bad or if the expander ball is the culprit. also if one side of the case neck is thicker than the other, when withdrawing the expander out of the case it will pull more on the thicker side and will cause a crooked neck, thus neck turning helps. you also might want to try a k&m taper case neck reamer:
http://www.lockstock.com/cart/webcart.cgi?ZOOMPAGE=YES&TOPPAGE=/products/zoomtop.txt&OCATS=K+&+M+Tapered+Case+Mouth+Reamer&ZN=TEXT&CODE=1877509&ITEM=3473
HTH.
Rick

bigcountry,..that runout on the bullet bearing surface being different points to unconcentric neck thickness as well as possible chamforing issues. The OUTSIDE of a sized neck is nice and round because the high spots have been pushed to the inside as it is run through a sizing die,..especially id the expander ball is eliminated as I do. Then,..the bullet being seated inside the neck,..has more pressure on it from the thick side of the neck. This combined with off-centered chamforing or no chamforing,..can compound the run-out. Beleive me,..neck turning is simple,..fast,..and worth the effort if you are after strict accuracy and not necessarily a "hunting" group,..but a "paper" group. I use it in even some of my factory chambered heavy barreled guns.

BC, before they carry you off in a strait jacket, try this: Load up 10 or 15 of your once fired rounds using your best techniques. Don't let them go near your concentricy (if thats a word) gauge. Now then, fire them using your best bench technique. Seperate any unexplained fliers. Reload only the cases that made the cut for accuracy using your best technique, etc, etc and fire them. If the pattern of fliers continue, the problem is not with your brass; but rather, with your press or dies. As assurance, you can load up the fliers and see if they also fit the pattern.

I think JustC and the others hit it on the head with mouth chamfering thing. I had great luck last week. No runout <.001". What did I do different this week? Well, I sized up a whole bunch of cases. They didn't need trimmed, so I barely deburred the inside with a wilson deburr tool kinda halfass'd. Bad Runout.

Last week, these were once fired, and trimmed and sized. So I had to deburr them real good. Good runout. I think I got it now.

If you are not turning your necks, you are wasting your time trying to fight neck runout other ways. It is common to find case necks that vary .002-003 in thickness. That alone will account for your runout. A week ago, I turned some 1902 Frankford Arsenal 30-40 brass that had .009 variance in thickness. Unless you have uniform neck thickness, you don't know what you are measuring. I don't know who told you neck turning was a negative. If done right, it can't hurt and most often helps. You may not be measuring lack of concentricity/runout at all..you very well may be measuring variation in case neck thickness.

Another benefit of neck turning is CONSISTANT NECK TENSION, lock of which will result in flyers. FWIW, I've had better luck with my dies floating than locked down. And no luck at all with RCBS dies. I use the Lee lock rings w/ the o-ring. I also like the Lee collet die. I doubt any of that is a substitute for bushing dies or straight line dies, but I can load 90%+ with .002" or less RO in the different chamberings I have.

Just to determine if runout is the problem, you might measure the runout in a batch of loaded rounds and then sort out the 10 with the least runout. Shoot those with the least runout in groups, and shoot some with more runout and see if there is a significant difference in group size between the two batches.

John

You have to find out where your runout is originating from. All your fired, unsized cases should show a
runout of zero. If you have runout at this point you've probably got a crooked chamber.

Run a fired case into your resizing die (remove the expander assembly first)measure the case. It'll tell you if
your die is okay. Screw the expander assembly back in and run another unsized, fired case into the
die. This will tell you if your expander ball is causing your runout if you measure the case right afterward.
Now, lastly prime and powder charge your case, seat the bullet and measure that to see if your bullet
seater is the culprit. This is admittedly a pain, but it will tell you where your problem is. At this point I'd
run out and buy me a Wilson NS knockout die and a little rawhide mallet. It's better than the heartache.
Best wishes.

Cal - Montreal

bigcountry,
Been there and done what you are trying to do regarding runout. Some of my 22/250 cases had runout as high as .008. It was not coming from my fired brass which had about .001. As Cal suggested you have to find the source. My chamfering of trimmed brass was terrible. The 40 year old trimmer was putting an uneven chamfer on the inside of the neck causing the bullet to seat badly. That fella was immediately trashed for a Wilson trimmer that does great. Other runout came from my defective RCBS dies. (They graciously replaced them). Another source of runout was caused by the tension put on the neck by the steel expander ball being withdrawn. A carbide expander ball stopped that problem. The last thing that cannot be overlooked is the runout contributed by uneven necks as other posters have suggested. You "can't polish crap". Two thou in neck variation will make about 3 or 4 thou at the bullet. This is all the good news.

The bad news: I tried to determine what effect up to .004 runout had on accuracy. I tried indexing the cases so they were put back in the chamber with the same orientation for the next shot. If I shot a good group, I kept the cases segregated and repeated the test; accuracy could not be repeated. Many rounds had runout of .001 to .002. Could not tell the difference between groups fired using ammo with .001 runout versus groups with .004 runout. Could not find any significant correlation between accuracy and runout.

I think a lot of my inaccuracy can be attributed to winds. A little wind goes a long way in throwing a bullet off at 200 yards. For example, from Sierra Infinity program, a 5 MPH crosswind from the left will drift a 70 gr. 223 Berger VLD 1.64 inches. A friend suggested working up loads at 50 yards to reduce the wind variable. At 50 yards that same bullet drifts only 0.16 in. BIG DIFFERENCE. At 50 yards we are looking at the gun or the shooter and not the unknown wind variable.

Let us know how it works out for you.
Ron

Hello Ron,

Good point on the wind. I have a .17Rem. While it does shoot light 25gr. bullets, it does so at 4000fps so
the velocity offsets the wind somewhat, but not enough. At my range the wind is always from behind you or
blowing in your face. Neither is a bad condition for accuracy. I shoot mainly from the bench and take my
time. Usually I'm shooting in near perfect conditions. My rifle will print a group of .4" (5 at 100yds.) and
precede or follow it with a 1.3" group. This is a common occurrence. I can only figure it's the wind.
You're quite right. It doesn't take much. Best wishes.

Cal - Montreal