need help with grouping

[GaCop]

ga cop-
what about getting a light ring in my bullets when seating them? could that be a sign. other than annealing what can i do? this brass is only on its third loading


The light ring on the bullet is from the seating stem and has no brearing on accuracy so can be ignored. What brass are you using? Try polishing the expander button on your sizing die to see if that helps. I use a Lee collet die and found neck tension is much more uniform and my neck runout is usually afround .002".

[calib]

ga cop-
what about getting a light ring in my bullets when seating them? could that be a sign. other than annealing what can i do? this brass is only on its third loading


The light ring on the bullet is from the seating stem and has no brearing on accuracy so can be ignored. What brass are you using? Try polishing the expander button on your sizing die to see if that helps. I use a Lee collet die and found neck tension is much more uniform and my neck runout is usually afround .002".


in simple terms can you explain runout

[keeki]

how much the entire loaded round is out of a true straight line from center point on the case head to the point of the bullet.

[keeki]

this is why I never use my sizing dies to decap. Decapping pins get bent while decapping and when it does it will cause runout.

[GaCop]

how much the entire loaded round is out of a true straight line from center point on the case head to the point of the bullet.


+1. There's bullet runout where the bullet is cocked in the case neck and when bad enough, you can see the bullet wobble when rolling the round on a sheet of glass. Neck runout causes the case neck to be cocked off center by a bad sizing die or bent expander stem.

[keeki]

I always use a universal decap die, its a must have if you use Lee collet dies.

[calib]

thanks for the info ill have to take a look and see if i can notice any wobble

[keeki]

to check this your gonna need a concentricity gauge. We're talking .003" is too much.

[l67coooled]

I had this same problem with my .308. I would have two or three touching then it would jump a inch or so up and group two more. I tried all sorts of things to tighten my groups to no avail. Come to find out my scope rings were loosening up and ever so slightly moving on me. Now i lock tight them and shot my best group of 4 shot .397" at 100 yds.