The second half of making precision ammo is to seat your bullet straight.
A well-made floating-bushing type of seater die is well worth it - to my knowledge Redding and Forster make good one. I would assume that the RCBS ones are good. The Hornady New Dimension dies are not good - they have the right idea, but their internal tolerances and clearances are sloppy enough that this completely defeats the idea behind such a design.
While not essential, having a micrometer adjustment on the seating die is very useful. In my ammo loading book I record the reading, so that I can return to it later. For example I loaded some .308 match ammo with a friend yesterday, my loadbook said that the last batch of ammo that I made for him (which shot very well) had been loaded "Redding +077" (translation: plus 77 thou on my Redding seating die,adjusted so that there is contact between it an the shellholder).
The first part of making precision ammo is to make sure that the brass is straight after you've sized it.
I have found some really cheap sizing dies (Lee F/L and Lee collet) to work well and make good straight brass, I have found some really expensive ones to work well (various Redding - body die, fixed neck die, bushing die, etc), and I have found some moderate and even expensive dies to not really make straight brass (or at least make it difficult to do so without some pretty subtle understanding of what is happening).
I don't really have time to go into this at length here, but a prime offender in making crooked brass is an expander ball of a poor design that has too much friction, takes a great deal of force to withdraw from the case mouth and ends up leaving crooked necks and sometimes irregularly stretched necks too (I am specifically ranting on RCBS here). Buttons made of carbide, or made in a more "bullet" shape can be better. One solution to to size your brass without using an expander at all, but there is a lot to discuss to do that right. Or if an expander ball is to be used, to lubricate the inside of the case mouth - which is labourious and messy.
(FWIW I am of the opinion that a micrometer adjustment on a sizing die is a waste - at least I haven't found a productive use for it.)
An important step in making good ammo is to acquire measuring tools, so that you can adjust your dies in a more sophisticated manner than the instructions tell you. E.g. instead of screwing the FL sizing die to contact the shellholder (which works, but usually ends up working the brass too much, and is by far the largest cause of unneeded stretching of cases and trimming, and short case life), you ought to be measuring the headspace dimension of brass fired in your rifle, and adjusting your dies to size your brass only a thou or two shorter. RCBS makes a "precision mic" that does this, there might be other comparable tools on the market now.
If you are loading with a press that uses conventional shellholders, Redding makes a set of shellholders in nonstandard height increments (in steps of two thou IIRC), which allows you to precisely control the headspace sizing dimension with the shellholder in contact with the die mouth.
You don't need a runout gauge on your bench, but it is nice to at least borrow one to use to set up your dies and establish your process. Once you've figured out how to make straight ammo, you can return your buddy's runout gauge ;-)
Kazimier
