I try to keep things simple when reloading, to the extent I can anyway. Would like to try a better quality die than my current standard RCBS. Don’t really want the added complexity of bushings, so who makes the most concentric FL expander ball dies? Yes, I realize looking for less runout with an expander ball is kinda contradictory, but let’s just go with it for the time being.

Forster, hands down.

Forster makes a great product. If you are planning to stick with a specific case mfr. you could also have them hone the neck of the die to better match up with the neck thickness and reduce overworking the brass. That can also help improve concentricity.

Which Forster model?

I like the specs on the Redding Master Hunter set. Well, other than the price tag! Anybody use these? Worth the bread?

Definitely and easily Forster. No question. Redding makes good dies but not on the same level. I just sent two sets of dies back to Redding because they both introduced .002-.004 wobble into the cases. The answer here is Forster. Seriously. As for the model, you said you wanted FL dies, so that's what I'd get.

The best FL size with expander ball is Forster honed to match the brass being used.

I just use their standard "Bench Rest" die sets. I have a couple of their micrometer seating dies, which are nice when playing with seating depth, but by no means required.

I've pretty much switched to Forster across the board, and my problems with runout have gone away. My run out gauge doesn't get much use anymore.

Very much appreciated. Thanks all. Forsters on order.

I never did try Forster FL dies. Over time I went from Hornady and RCBS FL sets to Redding FL sets, then moved on to Redding body dies, Lee collet neck dies and Forster seaters. I suppose if I was convinced I needed to move back to FL dies, I'd go Forster or possibly something like Whidden or some other custom maker. Not something I'm inclined to do, though.

Mighty Armory

I'm soundly in the Forster camp as well, but Reddings with their floating carbide expanders are also top notch.

Is concentricity a function of the tool or the brass?
If the tool I imagine that stem flex or expander ball float would be the culprit,
Though it still seems the brass is in control...
Like controlling a hockey puck way in front of you with one hand on the stick....

Both. Good dies can't make up for crap brass, crap dies will screw up good brass. Also important is how well the die and brass work together even when both are Independently straight. This is largely a function of how much the neck section of the die sizes the brass compared to how much the neck actually needs sizing.

Well put.
Thanks Mathman.

Just recently Gave these a go in 6mm ARC. Great for converting 6.5 Grendel to 6mm ARC. Ted is on to something here IMHO. Tried all other dies mentioned here at one time or another. Nothing has been as smooth as the Mighty Armory. If Mighty armory does a die for your caliber Id highly encourage giving them a try if you can get past the price.

Advantages -
1.) Smooth

2.) Simple

3.) Robust seating stem.

4.) Low runout.

5.) Doesn't over work the case.

6.) Wide de-caping pin options

Disadvantages

1.) Cost

2.) lock nut may be improved IMHO. Perhaps the lee lock nut?

I like Forster dies. Hasbeen

Yup, Forster BR FL die set is my preference. I prefer the micrometer seater to the standard BR seater, but it makes little difference if you're setting the die and leaving it there.

I also use the LCD/Redding BD/Forster seater, and both methods work equally well at producing straight ammo. In terms of sizing, the Forster FL is simpler and faster, but the LCD/Redding BD offers more flexibility in operation and use.

Pardon a dumb question but as somebody here always says, "Start at the start" (although that is usually interspersed with a few expletives).
So the question: what problems are you seeing with the RCBS dies and what is your technique? I have no problem getting <.001" runout with any of my RCBS dies so unless you are running them on a progressive or have a set up problem, how are you setting them up, what is your procedure and what is your goal?
I have no doubt the other manufacturers mentioned make superior dies but short of BR haven't seen the need for them.
If it's just to buy stuff, carry on.

If I send a Forster FL die in to get the neck honed, do I use the thinnest brass I have to figure out how much to have removed?

If you want it to work for all your brass, then yes.

I had my Forster 308 die honed to better match the thicker Lapua, Federal and LC brass because my RCBS die was just fine for the types with thinner necks.

What runout are we talking about?

Runout of sized brass. If we start talking about bullet runout, that seems to be beyond what the OP was asking and involves other dies. Personally I use mostly Forster for seating.
My concern is that the OP may be disappointed in his purchase if the problem is not with his current dies. A properly made FL die cannot induce runout.

Forster, because the neck is still held in alignment as the expander ball is being pulled through the neck, and Mighty Armory.

John

For the best FL sizing die there is not substitute.