Consentricity (.308 F-F class)

ron hilchey

ron hilchey

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Started measuring the consentricity of my .308 match ammo.
Useing Lee neck dies, and seater, Laupa brass, Laupa 155 seiners.
Any loaded rounds measuring over .004 are sorted out and marked on the lowest point.
Once reloaded and checked these rounds generally are out of spec in the same spot as they were marked before.
Am I correct in thinking that these particular pieces os brass are flawed?
Ron.
 
Where is the runout? On the case? On the bullet close to the neck? Way out on the end? What is a fired case telling you?
Nothing wrong with the brass but maybe check your shell holder or try only half seating your bullet, turn it 1/3 and finish seating it.
 
You can also use a ball mike to check the neck wall thickness. Variations do occur, but not as often with Norma or Lapua brass.

Is this affecting your groups? Try marking the "high" point on each cartridge and make a habit of always chambering with the mark at 6 o'clock or midnight.

Precision measures were invented to drive otherwise sane shooters batty.
 
mabey you already know this but there is a gadget you can get to turn the case necks to a uniform thickness, but dont ask me where to get one because I dont know, seen one in a magazine article one time.
 
I have been marking the low points on the brass, and chambering them all to the same reference point. The thing that I have noticed is that the low point is consistantly in the same place after repeated fireings on the same case.
 
Have you measured the wall thickness at the mouth of the case? Lapua is generally very good. See if you can borrow a another set of dies just to rule that out, and a shell holer too. I would avoid neck turning if at all possible.
 
Ron:

Most concentricity issues result from improper sizing/equipment. I'll loan you a bushing sizer for comparison. Please call.

Peter
 
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