Dahermit's numbers are pretty reasonable. Figure 0.003 TIR is 0.0015 of tip-tilt off-axis, and that should not be able to cause drift of more than around 0.2 moa radially away from a specific POI at 100 yards with most common bullet designs. Still pretty good precision.
I've been able to get down to about 0.002 TIR without neck turning and about half that with neck turning. PITA, though and only worth bothering with for some secant ogive designs.
The OP referenced conjunction of the NECO gauge and a hammer, which I found humorous. The former is a pretty delicate instrument and the latter is, well, not. NECO does sell
a universal correcting fixture, but I find I can drill holes in a piece of hardwood that I clamp to the bench that seems to work, even it isn't as nice. As long as it doesn't mar the bullet or burr the case in the correction process, it is adequate. You do have to get the feel of it, though that doesn't take long.
1stmar,
What determines how hard the brass grips the bullet is its modulus of elasticity, a measure of how hard it is to stretch within its elastic limits, and the yield point. Basically, you can make the interference fit to the neck tighter and tighter to increase bullet pull by elastic deformation up to the point the metal yields (plastic deformation), after which the metal gets bigger without increased elastic force being applied. If you go to
Matweb and look at different tempers of cartridge brass (different levels of annealing), you discover the modulus of elasticity is the same for all of them. In other words, the elastic force is the same regardless of annealing. What changes with hardness is the yield force, which is how much pressure you apply before it deforms plastically. So, a neck can be sized smaller to get higher bullet pull only until the amount the bullet expands it reaches the yield point of the brass. Since annealed brass has a lower yield, if you sized necks smaller and smaller, you would reach the limit below which no increase in bullet pull is achieved sooner with annealed brass. But if neither your annealed brass nor your work-hardened brass is being stretched to its yield point by the bullet expanding the resized neck, then, for cases with the same neck wall thickness and bullet seating depth, bullet pull will be the same. I'm convinced that sameness of the modulus of elasticity across different hardnesses is why Bryan Litz saw no difference in annealed brass in the tests he ran.
That said, there may be some hidden advantages to annealing. One thing is it should take a little less effort to straighten a bullet in an annealed case. Another is it should respond better to being straightened in your sizing die. Another is burning the carbon out of the neck should make its lubricity with the bullet more consistent, which would improve consistency of bullet pull. Another is the oxide layer, which is known to fend off corrosion of the brass in corrosive atmospheres, may help the loaded rounds keep from developing excessive bullet pull. Lots of possibilities are out there. Annealing cautions would include that over-annealing could reduce the yield point so much that even small amounts of stretching surpasses it and bullet pull is thereby reduced even for normal loading procedures (I haven't calculated that to see it's practical to make happen). Another is just that over-annealed brass develops neck splits more rapidly than properly annealed brass, so unless you anneal very frequently you can lose cases.
I would like to see someone do a comparison of FL resized cases, on not annealed until it splits and the other annealed ever time, to see which one develops the "dreaded donut" faster.
