Guys, the other day I measured the run-out on some .30-06 reloads. Fired, the cases had almost zero runout (measured on Sinclair Concentricity Gauge). I sized with a Lee Collet die, and found runout now typically between .001" and .002" - values I still consider pretty good, and not much to worry about in a big game rifle with a factory chamber. Seating the bullets with a Forster Ultra Competition Seater, I now got between .002 and .003" runout measured about half way up on the protruding bullet. This is probably still not much to worry about. But it surprised me a bit, since when we have discussed runout in the past, we usually focus on runout created in the sizing step.

I went back over some past posts, and the only thing I came across was suggestions that insufficient or improper deburring of the case might be a factor. The suggestion was to ensure sufficient deburring, that the bullet (in my case a flat-base 180 grs) could be "seated" nicely into the mouth of the case before starting the seating stroke.

If this is the case, what is the preferred tool(s) for such deburring?? Are the usual hand-held tools good enough, or are deburrers such as Wilson's mounted in their trimmer preferable?? And, what is the preferred angle on the deburring tool?? 45 degrees used to be standard, now you see all sorts of angles, but I can't figure out whether these steeper angles are suitable for all bullet types or only for BT/VLD type bullets???

Anybody??

- mike

P.S. I should add, my cases have not been outside neck turned, so it is possible that variance in neck thickness could have caused some of the runout??

Mike,



I believe there is a lot to this simple fact. My deburring tool is a Forester and the angle seems to be 30 degrees. When I use that tool and seat a bullet I can feel a uneven jump as the heel of the bullet forces it's way past that angle. The tool that I have been using for a long time now is a 15 degree tool that was in my dad's tooling. It's pretty old but I have sharpened it a number of times. I use a collet or chuck to hold it but a drill held in a vise should spin it just fine.



I press the case onto the chamfering tool at random angles. The tool, due maybe to it's age and iffy sharpening, even opens the necks some like a Lyman M die might but a lot less.



When a bullet is seated after using this tool the feel is very soft. In fact one can hardly feel the bullet entering the case at all the angle is so gentle.



I think this is a lot more important than runout under .003" as we may be measuring other stuff that does not matter at that point.



I saw a Lyman chamfering tool that seemed to have a gradual angle. It had a handle but any wood handle can be removed. I don't know what the inside shank might be in diameter in terms of chucking it up but I would think they might be just 1/4".

From everything I have heard about runout, 2 or 3 thou is not going to make much difference in shooting accuracy unless you are shooting benchrest. In tests last year, I could not find any correlation between accuracy and runout as high as .007. Other factors affected it more.

Not familiar with the Sinclair concentricity gauge; I use RCBS brand. What I find is that runout measured mid-way on the bullet will always be about double the runout measured at a case neck. As mentioned by "Savage", one can make the runout greater if the deburring is done too crudely. (K&M makes a deburring tool with a 15 degree angle.) I had an old case trimmer that put a very uneven chamfer on the case neck and sure enough the bullet went in crooked; the chamfer was so bad that one side of the neck was really chamfered while the other side was barely touched. That tool went in the trash; use a Wilson now for triming and an RCBS deburring tool. For seating, currently use the Forester Ultra Seater and believe it does an excellent job. One thing that I did find that affected my runout significantly was the expander ball (which you are not using with Lee Collet but will eventually have to use as cases grow). I switched to the carbide expander balls from Redding. This stopped a lot of my runout problems. Uneven (unturned) necks also add runout.

My theory is that if you jam the bullet into the lands by about .005, size half the neck and bump the shoulder back by about .001 (both done using Redding FL Bushing die), you get the best combo for accuracy. The bullet is aligned by the lands contact and the concentric ring around the lower part of the neck while the case can freely float in the chamber. Even though folks like to neck size, you face the problem of the ever growing case that eventually has to be resized and that case is now significantly differently than the one prior. By FL sizing all the time, you bring all cases back to the same standard dimension.

Ron
Charleston, WV

C210:

I thought this was a great post. One further thing to think about. When I want a rifle to shoot good I generally buy and use a Wilson straight line bullet seating die. They seem to keep every thing straighter during the seating process. Wilson says their die supports the case and bullet closer than press dies. Its easier to keep things in line this way. This won't eliminate sizing die troubles, uneven brass, or crooked chamber problems but it does eliminate bullet alignment problems.

knobmtn

If you have runout in your cases AFTER sizing with the collet die, that neck runout is enhanced when you've seated the bullet and measure it. It wouldn't have much to do with a seater but rather with the sizing. Think about it. You are measuring the bullet at a greater distance from the body which was straight and concentric after firing and hasn't been touched by a sizer. And, yes, differences in neck wall thickness will affect concentric bullet seating, just as burrs on the inside of the case mouth might. It's like putting a pebble under your foot. Burrs on one side of the neck and not the other, would have the same effect. But, it's not likely you got them using a collet die unless you trimmed. Bottom line, I think you're introducing your runout in the sizing step with your collet die.

I never had luck with the collet dies and sent mine back to Lee who was as good as their word in giving me my money back. It may be that center stud or whatever they call it, is a bit skewed in there helping to introduce runout. I think the die is where your problem lies.

I use the VLD deburring tool from Lyman for all deburring but it's only neccesary when you trim, not when you are just neck sizing.

If you're measuring runout on the neck after you size with the collet die it's most likely due to a variance in neck wall thickness. This is because the collet die sizes against a fixed mandrell from the inside. Any variance in neck wall thickness, therefore, will show up on the outside of the neck and will be measured as runout. I've had nothing but great performance out of my collet dies. I wouldn't use any other neck die.

As far as bullet seating is concerned, I recently started using the Redding Competition seater. It replaced the Forster Ultra benchrest seater I had been using before. This Redding seater has improved runout, not a lot mind you because I wasn't really having runout problems to begin with, but it definitely has made a difference.

One last thing. What press are you using? This can be a source of runout also. I use the Forster Co-Ax, which from everything I've ever heard, is better at producing concentric ammo than just about any other.

I'm in the process of cutting over to Wilson dies, and now have sets for three calibers. It's a bit expensive, but I should have done it years ago. It gets rid of a lot of concentricity heartaches. Best wishes.

Cal - Montreal

Cal/knobmtn
Tell me more about those Wilson dies. Currently use Wilson trimmer and case gauges and respect their quality and approach. Wilson has good stuff.

I assume the sizing and seater dies requre an arbor press. (My wife would love to see another box from a shooters supply house.) Do you have any data on runout before and after conversion to Wilson? Would love to hear more about your experiences or any other folks on the forum.

My Forester seaters thus far have not seemed to add any additional runout that I can detect.
Ron

Good thread. Agree with someone on the K&M chamfer tool. Its the cats ass!!

I get about .001-.002 bullet runout using all Forster dies and Win. brass. Iam sure Wilson and Redding's are good, but am I going to improve bullet/case runout that much with the others? If the answer is yes, I'll change today. Seriously!!...sakofan..

C210:

Here is a bit of what the Wilson website says:

"The cause is crooked bullet seating. Appreciating it requires a look at the bullet seating operation. The usual bullet-seater is a full-length die carrying an adjustable top screw which fits the bullet nose. The alignment of this screw is controlled by only the screw threads. Also the screw usually is quite loose, and takes different positions when the locknut is tightened. The die itself is aligned in the loading tool by only its screw threads. Moreover, while the cartridge case is being pushed into the die, its base receives no more alignment than what it gets from a loose fit in the case holder. Alignment of the case holder is no better than that of its one-sided lips and of the loading tool ram in which it is carried. When the case is finally pushed home in the die, the bullet has already been seated.

The chamber-type bullet seater positively controls both bullet and cartridge case throughout. The case is first put fully into the die, then the bullet is pushed straight into the case by a close-fitting plunger sliding in alignment. This seater works more accurately than the conventional bullet-seating die. Its cost is not great, and if desired it can be bought instead of the seating die in the usual die set."

I used straight line dies for a long while on my match rifles. With good quality, neck turned brass I was getting less than .001 neck run out. My factory guns varied. I actually don't remember what the runout was with press dies. It varied from gun to gun and even from time to time as I recall. But, I did mark the loaded rounds and observed that the ones with most runout were usually the ones that didn't go into the group or in other words became fliers. By making the switch to Wilson seating dies I eliminated the runout that came from the dies and the fliers pretty much went away. My original experiment was with a Sako 222 that wanted to shoot but had about one flier per group. It also did the same thing for a Model 7 in 243. I also use them in 17 Rem., and most recently I bought one in 7-08. That one cost me $32 at R.W. Hart. Sinclair sells them, too. I have some other custom dies but ehy are another story price wise. An arbor press helps but most of the time I am able to seat by hand if I want to. You can seat with a plastic mallet if you had to, I think.
I don't like the Wilson bushing neck dies for unturned necks. I prefer to F.L. size to fit the chamber. I think you said you're using carbide expanders so you should be ok on the necks with that. Straight line seaters are not going to fix run out from uneven case necks, bad chambers, or sizing die problems. They are just going to hold the case straight and line the bullet up and seat it straight.
Wilson claims that straight line seating gains a half minute of angle in a 30-06 over arsenal match ammo. I don't know for sure about that. But, I do know that at a benchrest match nearly 100% of the bullets are seated by straight line seating dies.

knobmtn

Here is food for thought.

When the case is sized without an expander, the runout ( as shown by a runout guage ) will be lower than that shown after bullet seating. Cuz the case body will align with the neck.

The hole the bullet goes in is offset an amount equal to the variance in neck wall thickness. When you seat a bullet, the variance is returned to the outside of the case where you can again see it with the guage.

I use an expander, and do not turn necks, I see variance more or less equal to the neck variance. It does not bother me to see it, it does bother the bullet when it's on the inside of the neck.

Case wall variance is something new for me to measure, takes time I really don't have. But, I got some answers long overdue from the trouble.

Travis F.