Brno308
Active Member
Handloader1, thanks for the suggestion. Is there a sure fire method of squaring dies or should I go with the rubber O ring method. All input is appreciated.
Handloader1, thanks for the suggestion. Is there a sure fire method of squaring dies or should I go with the rubber O ring method. All input is appreciated.
I have the Sinclair concentricity gauge.
I don't use it much, but I do a lot of things based on what I learned from using it.
A) The expander ball [pulling] used in the same step as FL sizing with FL die [in original configuration with neck not honed out] can bend the necks so bad that all other sins pale in comparison.
FL sizing with the same die with the expander ball removed, and then using expander ball [pushing ] in a separate step makes only 1/4 as much neck bending.
B Dies matter
1) Redding FL "S" dies cost the most and look the best, but are the worst for concentricity.
2) Forster FL dies with the neck honed out at the factory to my spec is in the middle.
3) Lee collet neck dies cost the least, look the worst, but make the best for concentricity.
C) Chambers matter
A tight neck no turn reamer is much better than a loose neck chamber made with a SAAMI reamer.
D) Brass matters.
How the S die bends necks is that it floats toward the side of the neck with thicker walls.
Lots of long range matches are won with unturned necks, but they sort for low run out in thickness.
Turning brass on the lathe takes skill. Sometimes I get .0001" and sometimes .0010"
The Lee Collet neck dies must be adjusted.
A big advantage for them with unturned necks is that the inside diameter of the neck is what ends up concentric, not the outside diameter.
~ 10 years ago I broke an RCBS rockchucker with a Lee Collet neck die adjusted to make the press just cam over at 100 pounds force on the knob. That makes infinite internal force, minus friction, in the press.