I’ve tested concentricity a bunch. It’s necessity is a bit over blown. Within reason.
I'm suspicious of that.
Laughing. Be suspicious of it all you like. Test it yourself.
Would like to hear your own tests, instead of what you Googled up....[/quote]
John, I shoot 1000’s of rounds some years (not this year) and have been handloading pretty seriously for 30 years. I used to chaise concentricity like it was the holy grail of accuracy. Why wouldn’t I? It’s all anyone could talk about at times. If you had flyers it must be crooked ammo. Right?
I bought die’s after die’s trying to eliminate one or two thou runout, had custom die’s made, went exclusively to a Forster Co-Axe, had bushings made, honed necks etc. This messing around with the necks of die’s was pretty much the catalyst that made me think twice about runout.
All this time I was thinking about annealing as well. For 20 years I have annealed brass. With candles, propane, using fingers, tempilaq, salt bath, and finally now an AMP. honestly if you aren’t using an AMP all you are doing is preventing split necks (now that ought to create angst).
Here is what I think. The idea that brass is the least important part of the handloaders recipe is nonsense. Why? Because the single biggest factor I have found in group consistency (not necessarily group size) is neck tension. To get consistent neck tension you need good brass, you need good dies and you need consistent annealing. Or no annealing at all.
In all of this, I also started to see runout not rearing it’s ugly head like I thought it should. Over the last couple of years I have tested that theory and have found loads with even 0.010 of runout landed right where they were supposed to. If you are getting more runout than that I’d suggest a mechanical overhaul.
I also think that powder charge matters (I use a lab grade scale), seating depth is huge (though seating depth close to, or into the lands is far from necessary or even preferred).
I’m no expert, but I’m not exactly green either. I’m developing loads in a hunting rifle context. I have my own private 1000 yard range and use it. If you are struggling with your groups I’d certainly not blame runout right away. It may not be the culprit at all.
