For you factory rifle guys--Most of your recoil lugs are stamped and not perfectly flat. So, If your receiver is flat, the recoil lug is not, and you thread your barrel down tight---then those straight bullets are not sitting in the chamber straight right? If you looked down the barrel (which I don't recommend) you should see your bullet not centered with the bore. What do you do about that, short of buying an expensive bench rifle?

Reloader,..consider this for a foundation of runout. You measure your case neck thickness at all 4 corners (4 90* points on the circumference of the neck) and you will often find up to .002" in variance, but a lot will be in the .001" and plus range. Now, that being said,..if you eliminate the expander ball and use the die to only size the OUTSIDE of the neck but not the inside,..you simply push the high spots into the inside. The difference is that the expander ball isn't being drug back through the neck while the die neck is still supporting it from the outside. This makes for a good smooth external dimension,..but not internal.Not to say that I have not and don't use this method also.

Now, the idea behind turning a neck is to eliminate the variances so that a neck can be sized with less effort and greater concentricity due to the lack of extra thickness which has to be "ironed out". So you can see how both internal and external dimensions are uniformed via that method.

The collet die, which I happen to be very fond of BTW, uses a different principle. Instead of the expander ball pulling upwards on the case and possibly moving it in the shellholder and/or changing it's orientation to the die body if it is a small bit larger, it simply sqeezes the neck around a mandral. That IMHO eliminates a great amount of possibility of error in alignment, and forms a better more concentric neck.

Try this,..turn down the expander ball a few 001's and see if your runout improves,..if not, then you aren't out anything anyway. You can always use the die without it. One thing I have found is that PFL sizing makes for a straight case with a good chamber fit as well.

I like to tinker so I do all these things for stress releif

quote:

I like to tinker so I do all these things for stress releif

I hear ya, kind of helps zone out the ole' Lady at times as well .

My 300WM Collet die is supposed to be delivered today, Looks like the RCBS Neck Sizer is going to collect alittle dust.

Have a Good One

Reloader

I'd need an ammunitio manufacturing plant to zone mine out