I friend of mine asked me to help figure out why his Win 70 in 243 would not group consistently week to week. I took the rifle and his dies and scrubbed the bore with solvent and copper cleaner and then went about loading some test loads. After loading several sets of three with a couple of different powders, I thought about checking them on my runout gauge. The runout was anywhere from .002 to .014 and this was a competition seater. I re-setup the die completely in my press and loaded a few more rounds. This time I got the runout down more consistently to .005 to .008. Anybody had this kind of problem with RCBS Competition seater dies before? My standard seater die will hold runout to about .002.

Some of the long needle point bullets will not seat well in any die. The point is so narrow that it can hit the flat bottom of the hole in the seater punch.

You should be able to roll long pointy bullet across a smooth table top and see no wobble.
For me that is about .003 or lesss.

IMO seaters very seldom create the problem, most often it is the sizing die. I have RCBS Competition Seaters in several calibers (love the side load window and straight start) and my runout is .0015" or less always. But I use a Lee Collet for sizing the neck which does not have an expander ball that needs to be jerked back through the neck when sizing.

YMMV

In my experience, most runout is caused by poor case necks; no seater can correct for that.

The design of the RCBS "Compitition" seater assures us that, on average, it's about as good as any conventional seater and those vary from reasonably good to unreasonalby poor. Ditto Hornady's short sliding sleeve seater desogn.

IMHO, the ONLY threaded seater dies worth calling "competition grade" are Forster and Redding and even they aren't quite up to the standards of most hand dies.

This really looks like the seater is the problem. I checked several of the sized cases that he gave me to load and they were straight. The needle on the dial indicator just vibrated a little as I turned the case. I was loading 100gr Sierra's and they are spitzers but not that pointed. I loaded a few with a standard seater die and the runout averaged about .002. I did have to use an extended shell holder to seat the bullets in the competition die so I guess it could be part of the problem. I have several comp dies from RCBS, Redding and Forester but have never had this problem. Generally .002 or less is the norm with those dies. I have never had to use an extended shell holder with any of mine but I don't normally load for a 243 either. Is there a way to check the extended shell holder to see if it is straight with the ram??