Bending a bullet or neck back into a straight position treats the symptom, not the problem. The problem that leads to non-concentric ammo is a combination of brass prep and tools used that change the shape of the brass. Could also add in reloading technique.
If your reloading technique yields "consistent" results - regardless if concentric or crooked, then you should feel confident your reloading techniques being used are solid, it's just identifying steps you are not taking (brass prep) and a critical eye on your forming and seating dies.
That is if you believe concentric ammo is worth pursuing. I do believe it contributes. Any one step may not be measurable, but all the added steps are cumulative - which is where you will see an improvement.
If you choose to bypass neck turning - it's my opinion you're limited to a Lee Collet Die, and a good seating die that supports the whole case when seating. Neck turning does not negate the positive impacts of the above tools either.
Choosing the right combination of components contributes as well, think barrel harmonics, low SD and low ES. If one reload is 100 fps faster than the next - how can it possibly have the same point of impact very far down the range?
If the bullet comes out the end of the barrel the same every time, it will hit the same place on the target. It's just that simple.
Of course - this is all just my opinion, and your mileage may vary.
Last edited by Burr; 03/15/16.
